Incidence and causes of end-stage renal disease among Aboriginal children and young adults

Background:

Although Aboriginal adults have a higher risk of end-stage renal disease than non-Aboriginal adults, the incidence and causes of end-stage renal disease among Aboriginal children and young adults are not well described.

Methods:

We calculated age- and sex-specific incidences of end-stage renal disease among Aboriginal people less than 22 years of age using data from a national organ failure registry. Incidence rate ratios were used to compare rates between Aboriginal and white Canadians. To contrast causes of end-stage renal disease by ethnicity and age, we calculated the odds of congenital diseases, glomerulonephritis and diabetes for Aboriginal people and compared them with those for white people in the following age strata: 0 to less than 22 years, 22 to less than 40 years, 40 to less than 60 years and older than 60 years.

Results:

Incidence rate ratios of end-stage renal disease for Aboriginal children and young adults (age < 22 yr, v. white people) were 1.82 (95% confidence interval [CI] 1.40–2.38) for boys and 3.24 (95% CI 2.60–4.05) for girls. Compared with white people, congenital diseases were less common among Aboriginal people aged less than 22 years (odds ratio [OR] 0.56, 95% CI 0.36–0.86), and glomerulonephritis was more common (OR 2.18, 95% CI 1.55–3.07). An excess of glomerulonephritis, but not diabetes, was seen among Aboriginal people aged 22 to less than 40 years. The converse was true (higher risk of diabetes, lower risk of glomerulonephritis) among Aboriginal people aged 40 years and older.

Interpretation:

The incidence of end-stage renal disease is higher among Aboriginal children and young adults than among white children and young adults. This higher incidence may be driven by an increased risk of glomerulonephritis in this population.Compared with white Canadians, Aboriginal Canadians have a higher prevalence of end-stage renal disease,^1,2 which is generally attributed to their increased risk for diabetes. However, there has been limited investigation of the incidence and causes of end-stage renal disease among Aboriginal children and young adults. Because most incident cases of diabetes are identified in middle-aged adults, an excess risk of end-stage renal disease in young people would not be expected if the high risk of diabetes is responsible for higher overall rates of end-stage renal disease among Aboriginal people. About 12.3% of children with end-stage renal disease in Canada are Aboriginal,³ but only 6.1% of Canadian children (age < 19 yr) are Aboriginal.^4,5A few reports suggest that nondiabetic renal disease is common among Aboriginal populations in North America.^2,6–8 Aboriginal adults in Saskatchewan are twice as likely as white adults to have end-stage renal disease caused by glomerulonephritis,^7,8 and an increased rate of mesangial proliferative glomerulonephritis has been reported among Aboriginal people in the United States.^6,9 These studies suggest that diabetes may be a comorbid condition rather than the sole cause of kidney failure among some Aboriginal people in whom diabetic nephropathy is diagnosed using clinical features alone.We estimated incidence rates of end-stage renal disease among Aboriginal children and young adults in Canada and compared them with the rates seen among white children and young adults. In addition, we compared relative odds of congenital renal disease, glomerulonephritis and diabetic nephropathy in Aboriginal people with the relative odds of these conditions in white people.     

Tobacco, alcohol and illicit drug use among Aboriginal youth living off-reserve: results from the Youth Smoking Survey

Background

Despite the high prevalence of smoking among Aboriginal youth, there is a paucity of research related to tobacco use and other risk behaviours among Aboriginal youth living off-reserve in Canada. We used data from the national Youth Smoking Survey to characterize non-traditional tobacco use, exposure to second-hand smoke, and alcohol and drug use among Aboriginal youth living off-reserve. We examined whether these youth were at increased health risk compared with non-Aboriginal youth.

Methods

We examined cigarette smoking behaviour, use of other tobacco products, use of alcohol and other drugs, and exposure to second-hand smoke among 2620 Aboriginal youth living off-reserve and 26 223 non-Aboriginal youth in grades 9 to 12 who participated in the 2008/09 Youth Smoking Survey.

Results

The prevalence of current smoking among the Aboriginal youth was more than double that among non-Aboriginal youth (24.9% v. 10.4%). Aboriginal youth also had a higher prevalence of regular exposure to second-hand smoke at home (37.3% v. 19.7%) and in cars (51.0% v. 30.3%). Aboriginal youth were more likely than non-Aboriginal youth to be current smokers, to be regularly exposed to second-hand smoke, to have tried marijuana and other illicit drugs, and to engage in binge drinking. They were less likely than non-Aboriginal youth to have tried to quit smoking.

Interpretation

Current national estimates of smoking, and alcohol and illicit drug use among youth underestimate the prevalence of these behaviours among Aboriginal youth living off-reserve. Our findings highlight the need for culturally appropriate prevention and cessation policies and programs for this at-risk population.Compared with the general population in Canada, Aboriginal youth start smoking earlier¹ and have a higher prevalence of smoking,^1–3 with female Aboriginals at greatest risk.¹ Research has also shown that Aboriginal youth have high rates of binge drinking¹ and are more likely than non-Aboriginal youth to use marijuana.⁴Despite the high prevalence of smoking among Aboriginal youth in Canada, there is a paucity of research related to their patterns of tobacco use, especially among Aboriginals living off-reserve.⁵ Most Aboriginals in Canada live off-reserve,⁶ and those 15 years of age and older are more likely than non-Aboriginals to have chronic health conditions, to drink heavily and to smoke.⁷ Given that the Canadian Tobacco Control Strategy emphasizes targeting youth, young adults, First Nations, Inuit and other Aboriginal groups,⁸ a better understanding of tobacco use among Aboriginal youth living off-reserve is required.We conducted this study to examine patterns of tobacco use, exposure to second-hand smoke and the prevalence of alcohol and other drug use among Aboriginal youth living off-reserve. We compared these data with those for non-Aboriginal youth using nationally representative data from the 2008/09 Youth Smoking Survey.     

Prevalence of and factors associated with head impact during falls in older adults in long-term care

Background:

Falls cause more than 60% of head injuries in older adults. Lack of objective evidence on the circumstances of these events is a barrier to prevention. We analyzed video footage to determine the frequency of and risk factors for head impact during falls in older adults in 2 long-term care facilities.

Methods:

Over 39 months, we captured on video 227 falls involving 133 residents. We used a validated questionnaire to analyze the mechanisms of each fall. We then examined whether the probability for head impact was associated with upper-limb protective responses (hand impact) and fall direction.

Results:

Head impact occurred in 37% of falls, usually onto a vinyl or linoleum floor. Hand impact occurred in 74% of falls but had no significant effect on the probability of head impact (p = 0.3). An increased probability of head impact was associated with a forward initial fall direction, compared with backward falls (odds ratio [OR] 2.7, 95% confidence interval [CI] 1.3–5.9) or sideways falls (OR 2.8, 95% CI 1.2–6.3). In 36% of sideways falls, residents rotated to land backwards, which reduced the probability of head impact (OR 0.2, 95% CI 0.04–0.8).

Interpretation:

Head impact was common in observed falls in older adults living in long-term care facilities, particularly in forward falls. Backward rotation during descent appeared to be protective, but hand impact was not. Attention to upper-limb strength and teaching rotational falling techniques (as in martial arts training) may reduce fall-related head injuries in older adults.Falls from standing height or lower are the cause of more than 60% of hospital admissions for traumatic brain injury in adults older than 65 years.^1–5 Traumatic brain injury accounts for 32% of hospital admissions and more than 50% of deaths from falls in older adults.^1,6–8 Furthermore, the incidence and age-adjusted rate of fall-related traumatic brain injury is increasing,^1,9 especially among people older than 80 years, among whom rates have increased threefold over the past 30 years.¹⁰ One-quarter of fall-related traumatic brain injuries in older adults occur in long-term care facilities.¹The development of improved strategies to prevent fall-related traumatic brain injuries is an important but challenging task. About 60% of residents in long-term care facilities fall at least once per year,¹¹ and falls result from complex interactions of physiologic, environmental and situational factors.^12–16 Any fall from standing height has sufficient energy to cause brain injury if direct impact occurs between the head and a rigid floor surface.^17–19 Improved understanding is needed of the factors that separate falls that result in head impact and injury from those that do not.^1,10 Falls in young adults rarely result in head impact, owing to protective responses such as use of the upper limbs to stop the fall, trunk flexion and rotation during descent.^20–23 We have limited evidence of the efficacy of protective responses to falls among older adults.In the current study, we analyzed video footage of real-life falls among older adults to estimate the prevalence of head impact from falls, and to examine the association between head impact, and biomechanical and situational factors.     

Hypertriglyceridemic-waist phenotype and glucose intolerance among Canadian Inuit: the International Polar Year Inuit Health Survey for Adults 2007�C2008

Background

Inuit have not experienced an epidemic in type 2 diabetes mellitus, and it has been speculated that they may be protected from obesity’s metabolic consequences. We conducted a population-based screening for diabetes among Inuit in the Canadian Arctic and evaluated the association of visceral adiposity with diabetes.

Methods

A total of 36 communities participated in the International Polar Year Inuit Health Survey. Of the 2796 Inuit households approached, 1901 (68%) participated, with 2595 participants. Households were randomly selected, and adult residents were invited to participate. Assessments included anthropometry and fasting plasma lipids and glucose, and, because of survey logistics, only 32% of participants underwent a 75 g oral glucose tolerance test. We calculated weighted prevalence estimates of metabolic risk factors for all participants.

Results

Participants’ mean age was 43.3 years; 35% were obese, 43.8% had an at-risk waist, and 25% had an elevated triglyceride level. Diabetes was identified in 12.2% of participants aged 50 years and older and in 1.9% of those younger than 50 years. A hypertriglyceridemic-waist phenotype was a strong predictor of diabetes (odds ratio [OR] 8.6, 95% confidence interval [CI] 2.1–34.6) in analyses adjusted for age, sex, region, family history of diabetes, education and use of lipid-lowering medications.

Interpretation

Metabolic risk factors were prevalent among Inuit. Our results suggest that Inuit are not protected from the metabolic consequences of obesity, and that their rate of diabetes prevalence is now comparable to that observed in the general Canadian population. Assessment of waist circumference and fasting triglyceride levels could represent an efficient means for identifying Inuit at high risk for diabetes.Indigenous people across the Arctic continue to undergo cultural transitions that affect all dimensions of life, with implications for emerging obesity and changes in patterns of disease burden.^1–3 A high prevalence of obesity among Canadian Inuit has been noted,^3,4 and yet studies have suggested that the metabolic consequences of obesity may not be as severe among Inuit as they are in predominantly Caucasian or First Nations populations.^4–6 Conversely, the prevalence of type 2 diabetes mellitus, which was noted to be rare among Inuit in early studies,^7,8 now matches or exceeds that of predominately Caucasian comparison populations in Alaska and Greenland.^9–11 However, in Canada, available reports suggest that diabetes prevalence among Inuit remains below that of the general Canadian population.^3,12Given the rapid changes in the Arctic and a lack of comprehensive and uniform screening assessments, we used the International Polar Year Inuit Health Survey for Adults 2007–2008 to assess the current prevalence of glycemia and the toll of age and adiposity on glycemia in this population. However, adiposity is heterogeneous, and simple measures of body mass index (BMI) in kg/m² and waist circumference do not measure visceral adiposity (or intra-abdominal adipose tissue), which is considered more deleterious than subcutaneous fat.¹³ Therefore, we evaluated the “hypertriglyceridemic-waist” phenotype (i.e., the presence of both an at-risk waist circumference and an elevated triglyceride level) as a proxy indicator of visceral fat.^13–15     

A qualitative investigation of smoke-free policies on hospital property

Background:

Many hospitals have adopted smoke-free policies on their property. We examined the consequences of such polices at two Canadian tertiary acute-care hospitals.

Methods:

We conducted a qualitative study using ethnographic techniques over a six-month period. Participants (n = 186) shared their perspectives on and experiences with tobacco dependence and managing the use of tobacco, as well as their impressions of the smoke-free policy. We interviewed inpatients individually from eight wards (n = 82), key policy-makers (n = 9) and support staff (n = 14) and held 16 focus groups with health care providers and ward staff (n = 81). We also reviewed ward documents relating to tobacco dependence and looked at smoking-related activities on hospital property.

Results:

Noncompliance with the policy and exposure to secondhand smoke were ongoing concerns. Peoples’ impressions of the use of tobacco varied, including divergent opinions as to whether such use was a bad habit or an addiction. Treatment for tobacco dependence and the management of symptoms of withdrawal were offered inconsistently. Participants voiced concerns over patient safety and leaving the ward to smoke.

Interpretation:

Policies mandating smoke-free hospital property have important consequences beyond noncompliance, including concerns over patient safety and disruptions to care. Without adequately available and accessible support for withdrawal from tobacco, patients will continue to face personal risk when they leave hospital property to smoke.Canadian cities and provinces have passed smoking bans with the goal of reducing people’s exposure to secondhand smoke in workplaces, public spaces and on the property adjacent to public buildings.^1,2 In response, Canadian health authorities and hospitals began implementing policies mandating smoke-free hospital property, with the goals of reducing the exposure of workers, patients and visitors to tobacco smoke while delivering a public health message about the dangers of smoking.^2–5 An additional anticipated outcome was the reduced use of tobacco among patients and staff. The impetuses for adopting smoke-free policies include public support for such legislation and the potential for litigation for exposure to second-hand smoke.^2,4Tobacco use is a modifiable risk factor associated with a variety of cancers, cardiovascular diseases and respiratory conditions.^6–11 Patients in hospital who use tobacco tend to have more surgical complications and exacerbations of acute and chronic health conditions than patients who do not use tobacco.^6–11 Any policy aimed at reducing exposure to tobacco in hospitals is well supported by evidence, as is the integration of interventions targetting tobacco dependence.¹² Unfortunately, most of the nearly five million Canadians who smoke will receive suboptimal treatment,¹³ as the routine provision of interventions for tobacco dependence in hospital settings is not a practice norm.^14–16 In smoke-free hospitals, two studies suggest minimal support is offered for withdrawal, ^17,18 and one reports an increased use of nicotine-replacement therapy after the implementation of the smoke-free policy.¹⁹Assessments of the effectiveness of smoke-free policies for hospital property tend to focus on noncompliance and related issues of enforcement.^17,20,21 Although evidence of noncompliance and litter on hospital property^2,17,20 implies ongoing exposure to tobacco smoke, half of the participating hospital sites in one study reported less exposure to tobacco smoke within hospital buildings and on the property.¹⁸ In addition, there is evidence to suggest some decline in smoking among staff.^18,19,21,22We sought to determine the consequences of policies mandating smoke-free hospital property in two Canadian acute-care hospitals by eliciting lived experiences of the people faced with enacting the policies: patients and health care providers. In addition, we elicited stories from hospital support staff and administrators regarding the policies.     

Development of guidelines for recently arrived immigrants and refugees to Canada: Delphi consensus on selecting preventable and treatable conditions

Background:

Setting priorities is critical to ensure guidelines are relevant and acceptable to users, and that time, resources and expertise are used cost-effectively in their development. Stakeholder engagement and the use of an explicit procedure for developing recommendations are critical components in this process.

Methods:

We used a modified Delphi consensus process to select 20 high-priority conditions for guideline development. Canadian primary care practitioners who care for immigrants and refugees used criteria that emphasize inequities in health to identify clinical care gaps.

Results:

Nine infectious diseases were selected, as well as four mental health conditions, three maternal and child health issues, caries and periodontal disease, iron-deficiency anemia, diabetes and vision screening.

Interpretation:

Immigrant and refugee medicine covers the full spectrum of primary care, and although infectious disease continues to be an important area of concern, we are now seeing mental health and chronic diseases as key considerations for recently arriving immigrants and refugees.Canada consistently receives more than 239 000 immigrants yearly, up to 35 000 of whom are refugees.¹ Many arrive with similar or better self-reported health than the general Canadian population reports, a phenomenon described as the “healthy immigrant effect.”^2–6 However, subgroups of immigrants, for example refugees, face health disparities and often a greater burden of infectious diseases.^7,8 These health issues sometimes differ from the general population because of differing disease exposures, vulnerabilities, social determinants of health and access to health services before, during and after migration. Cultural and linguistic differences combined with lack of evidence-based guidelines can contribute to poor delivery of services.^9,10Community-based primary health care practitioners see most of the immigrants and refugees who arrive in Canada. This is not only because Canada’s health system centres on primary care practice, but also because people with lower socioeconomic status, language barriers and less familiarity with the system are much less likely to receive specialist care.¹¹Guideline development can be costly in terms of time, resources and expertise.¹² Setting priorities is critical, particularly when dealing with complex situations and limited resources.¹³ There is no standard algorithm on who should and how they should determine top priorities for guidelines, although burden of illness, feasibility and economic considerations are all important.¹⁴ Stakeholder engagement to ensure relevance and acceptability, and the use of an explicit procedure for developing recommendations are critical in guideline development.^15–17 We chose primary care practitioners, particularly those who care for immigrants and refugees, to help the guideline committee select conditions for clinical preventive guidelines for immigrants and refugees with a focus on the first five years of settlement.     

Association of practice size and pay-for-performance incentives with the quality of diabetes management in primary care

Background:

Not enough is known about the association between practice size and clinical outcomes in primary care. We examined this association between 1997 and 2005, in addition to the impact of the Quality and Outcomes Framework, a pay-for-performance incentive scheme introduced in the United Kingdom in 2004, on diabetes management.

Methods:

We conducted a retrospective open-cohort study using data from the General Practice Research Database. We enrolled 422 general practices providing care for 154 945 patients with diabetes. Our primary outcome measures were the achievement of national treatment targets for blood pressure, glycated hemoglobin (HbA_1c) levels and total cholesterol.

Results:

We saw improvements in the recording of process of care measures, prescribing and achieving intermediate outcomes in all practice sizes during the study period. We saw improvement in reaching national targets after the introduction of the Quality and Outcomes Framework. These improvements significantly exceeded the underlying trends in all practice sizes for achieving targets for cholesterol level and blood pressure, but not for HbA_1c level. In 1997 and 2005, there were no significant differences between the smallest and largest practices in achieving targets for blood pressure (1997 odds ratio [OR] 0.98, 95% confidence interval [CI] 0.82 to 1.16; 2005 OR 0.92, 95% CI 0.80 to 1.06 in 2005), cholesterol level (1997 OR 0.94, 95% CI 0.76 to 1.16; 2005 OR 1.1, 95% CI 0.97 to 1.40) and glycated hemoglobin level (1997 OR 0.79, 95% CI 0.55 to 1.14; 2005 OR 1.05, 95% CI 0.93 to 1.19).

Interpretation:

We found no evidence that size of practice is associated with the quality of diabetes management in primary care. Pay-for-performance programs appear to benefit both large and small practices to a similar extent.There is a well-established body of literature showing positive associations between volume of patients and clinical outcomes in health care, which has been documented by a systematic review.¹ However, this association has usually been examined in a limited number of discrete procedures, and most studies have involved hospital-based services rather than primary care settings.^2–5Improving our understanding of the association between volume of patients and outcomes in primary care is important for several reasons. First, most contacts with health systems occur in primary care settings, and optimizing the delivery of these services has the potential to improve the health of the population.⁶ Second, over the past decade, primary care has assumed greater responsibility for managing the growing burden of chronic disease.^7,8 Larger providers may be better resourced, through the employment of additional support staff and greater use of information technology, to deliver the systematic, structured care necessary for the effective management of chronic disease.^6,9 Third, larger providers may have been more responsive to nonfinancial and financial incentives, including pay for performance, implemented by payers aimed at improving the quality of care.^7,10 Fourth, in many countries, primary care is based around a predominance of small practices.^6,11,12 In 2006, 53% of practices in England and Wales had three or fewer family physicians.¹¹ In the same year in the United States, 30.3% of family physicians were in solo practice; 9.4% were in two-physician practices.¹²Despite the limited data available, concerns have been raised about the standards of care delivered by smaller family practices.¹³ In the United Kingdom and Canada, this has resulted in an explicit policy objective of encouraging smaller practices to amalgamate.^13,14Our study examines the associations between the size of practice and the quality of diabetes management in UK primary care settings between 1997 and 2005. We tested the hypotheses that patients attending larger family practices receive better care for diabetes and that the quality gap between larger and smaller practices has increased over the past decade. We also hypothesized that larger practices derived more benefit from the Quality and Outcomes Framework, a major pay-for-performance program in primary care introduced in 2004.     

Risk of herpes zoster among patients with chronic obstructive pulmonary disease: a population-based study

Background

Systemic inflammation and dysregulated immune function in chronic obstructive pulmonary disease (COPD) is hypothesized to predispose patients to development of herpes zoster. However, the risk of herpes zoster among patients with COPD is undocumented. We therefore aimed to investigate the risk of herpes zoster among patients with COPD.

Methods

We conducted a cohort study using data from the Taiwan Longitudinal Health Insurance Database. We performed Cox regressions to compare the hazard ratio (HR) of herpes zoster in the COPD cohort and in an age- and sex-matched comparison cohort. We divided the patients with COPD into three groups according to use of steroid medications and performed a further analysis to examine the risk of herpes zoster.

Results

The study included 8486 patients with COPD and 33 944 matched control patients. After adjustment for potential confounding factors, patients with COPD were more likely to have incidents of herpes zoster (adjusted HR 1.68, 95% confidence interval [CI] 1.45–1.95). When compared with the comparison cohort, the adjusted HR of herpes zoster was 1.67 (95% CI 1.43–1.96) for patients with COPD not taking steroid medications. The adjusted HR of herpes zoster was slightly greater for patients with COPD using inhaled corticosteroids only (adjusted HR 2.09, 95% CI 1.38–3.16) and was greatest for patients with COPD using oral steroids (adjusted HR 3.00, 95% CI 2.40–3.75).

Interpretation

Patients with COPD were at increased risk of herpes zoster relative to the general population. The relative risk of herpes zoster was greatest for patients with COPD using oral steroids.Herpes zoster is caused by a reactivation of latent varicella-zoster virus residing in sensory ganglia after an earlier episode of varicella.¹ Herpes zoster is characterized by a painful vesicular dermatomal rash. It is commonly complicated with chronic pain (postherpetic neuralgia), resulting in reduced quality of life and functional disability to a degree comparable to that experienced by patients with congestive heart failure, diabetes mellitus and major depression.^1,2 Patients with herpes zoster experience more substantial role limitations resulting from emotional and physical problems than do patients with congestive heart failure or diabetes.³ Pain scores for postherpetic neuralgia have been shown to be as high as those for chronic pain from osteoarthritis and rheumatoid arthritis.³ Although aging is the most well-known risk factor for herpes zoster, people with diseases associated with impaired immunity, such as malignancy, HIV infection, diabetes and rheumatic diseases, are also at higher risk for herpes zoster.^4,5Chronic obstructive pulmonary disease (COPD) is characterized by progressive airflow limitation that is associated with an abnormal inflammatory response by the small airways and alveoli to inhaled particles and pollutants.⁶ Disruption of local defence systems (e.g., damage to the innate immune system, impaired mucociliary clearance) predispose patients with COPD to respiratory tract infections. Each infection can cause exacerbation of COPD and further deterioration of lung function, which in turn increase predisposition to infection.^7,8There is increasing evidence that COPD is an autoimmune disease, with chronic systemic inflammation involving more than just the airways and lungs.⁶ Given that various immune-mediated diseases (e.g., rheumatoid arthritis, inflammatory bowel disease) have been reported to be associated with an increased risk of herpes zoster,^4,9,10 it is reasonable to hypothesize that the immune dysregulation found in COPD may put patients at higher risk of developing herpes zoster. In addition, inhaled or systemic corticosteroids used for management of COPD can increase susceptibility to herpes zoster by suppressing normal immune function.¹¹ However, data are limited regarding the risk of herpes zoster among patients with COPD.The goal of our study was to investigate whether patients with COPD have a higher incidence of herpes zoster than the general population. In addition, we aimed to examine the risk for herpes zoster with and without steroid therapy among patients with COPD relative to the general population.     

Telehealthcare for asthma: a Cochrane review

Background:

Telehealthcare has the potential to provide care for long-term conditions that are increasingly prevalent, such as asthma. We conducted a systematic review of studies of telehealthcare interventions used for the treatment of asthma to determine whether such approaches to care are effective.

Methods:

We searched the Cochrane Airways Group Specialised Register of Trials, which is derived from systematic searches of bibliographic databases including CENTRAL (the Cochrane Central Register of Controlled Trials), MEDLINE, Embase, CINAHL (Cumulative Index to Nursing and Allied Health Literature) and PsycINFO, as well as other electronic resources. We also searched registers of ongoing and unpublished trials. We were interested in studies that measured the following outcomes: quality of life, number of visits to the emergency department and number of admissions to hospital. Two reviewers identified studies for inclusion in our meta-analysis. We extracted data and used fixedeffect modelling for the meta-analyses.

Results:

We identified 21 randomized controlled trials for inclusion in our analysis. The methods of telehealthcare intervention these studies investigated were the telephone and video- and Internet-based models of care. Meta-analysis did not show a clinically important improvement in patients’ quality of life, and there was no significant change in the number of visits to the emergency department over 12 months. There was a significant reduction in the number of patients admitted to hospital once or more over 12 months (risk ratio 0.25 [95% confidence interval 0.09 to 0.66]).

Interpretation:

We found no evidence of a clinically important impact on patients’ quality of life, but telehealthcare interventions do appear to have the potential to reduce the risk of admission to hospital, particularly for patients with severe asthma. Further research is required to clarify the cost-effectiveness of models of care based on telehealthcare.There has been an increase in the prevalence of asthma in recent decades,^1–3 and the Global Initiative for Asthma estimates that 300 million people worldwide now have the disease.⁴ The highest prevalence rates (30%) are seen in economically developed countries.^5–8 There has also been an increase in the prevalence of asthma affecting both children and adults in many economically developing and transition countries.^9–11Asthma’s high burden of disease requires improvements in access to treatments.^7,12,13 Patterns of help-seeking behaviour are also relevant: delayed reporting is associated with morbidity and the need for emergency care.It is widely believed that telehealthcare interventions may help address some of the challenges posed by asthma by enabling remote delivery of care, facilitating timely access to health advice, supporting self-monitoring and medication concordance, and educating patients on avoiding triggers.^14–16 The precise role of these technologies in the management of care for people with long-term respiratory conditions needs to be established.¹⁷The objective of this study was to systematically review the effectiveness of telehealthcare interventions among people with asthma in terms of quality of life, number of visits to the emergency department and admissions to hospital for exacerbations of asthma.     

The Cedar Project: risk factors for transition to injection drug use among young, urban Aboriginal people

Background:

Studies suggest that Aboriginal people in Canada are over-represented among people using injection drugs. The factors associated with transitioning to the use of injection drugs among young Aboriginal people in Canada are not well understood.

Methods:

The Cedar Project is a prospective cohort study (2003–2007) involving young Aboriginal people in Vancouver and Prince George, British Columbia, who use illicit drugs. Participants’ venous blood samples were tested for antibodies to HIV and the hepatitis C virus, and drug use was confirmed using saliva screens. The primary outcomes were use of injection drugs at baseline and tranisition to injection drug use in the six months before each follow-up interview.

Results:

Of 605 participants, 335 (55.4%) reported using injection drugs at baseline. Young people who used injection drugs tended to be older than those who did not, female and in a relationship. Participants who injected drugs were also more likely than those who did not to have been denied shelter because of their drug use, to have been incarcerated, to have a mental illness and to have been involved in sex work. Transition to injection drug use occurred among 39 (14.4%) participants, yielding a crude incidence rate of 19.8% and an incidence density of 11.5 participants per 100 person-years. In unadjusted analysis, transition to injection drug use was associated with being female (odds ratio [OR] 1.98, 95% confidence interval (CI) 1.06–3.72), involved in sex work (OR 3.35, 95% CI 1.75–6.40), having a history of sexually transmitted infection (OR 2.01, 95% CI 1.07–3.78) and using drugs with sex-work clients (OR 2.51, 95% CI 1.19–5.32). In adjusted analysis, transition to injection drug use remained associated with involvement in sex work (adjusted OR 3.94, 95% CI 1.45–10.71).

Interpretation:

The initiation rate for injection drug use of 11.5 participants per 100 person-years among participants in the Cedar Project is distressing. Young Aboriginal women in our study were twice as likely to inject drugs as men, and participants who injected drugs at baseline were more than twice as likely as those who did not to be involved in sex work.Aboriginal leadership in Canada is deeply concerned about substance use, more specifically injection drug use and its association with the spread of HIV and the hepatitis C virus among Aboriginal young people.^1,2 Recent studies in Canada suggest that Aboriginal people are over-represented among people who use injection drugs.^3,4 For Aboriginal young people in Canada under the age of 24 years, injection drug use accounts for the majority of infections with the hepatitis C virus (70%–80%)^5,6 and over half (59%) of HIV infections.⁷Indigenous scholars have stated that research on substance use within Aboriginal communities must consider the context of colonization, including the intergenerational impacts of the residential school and child welfare systems.^8–11 It is now well documented that Aboriginal children experienced extensive psychological, sexual, physical and emotional abuses within those systems.^12,13 As former students of residential schools raise children and grandchildren, the intergenerational effects of abuse and familial fragmentation are evident in communities where interpersonal violence and drug dependence are pervasive.^14–16A priority for preventing infections with HIV and hepatitis C among young Aboriginal people is the development of programs and rights-based,^18,19 youth-informed¹⁷ policies aimed at preventing the use of injection drugs. However, research to date has not provided sufficient evidence to inform such development.^2,19 Concerns over this paucity of information led to the launch of a two-city cohort study in 2003 to address HIV-related vulnerabilities among young Aboriginal people in British Columbia — a unique study centred on at-risk youth and supported by and partnered with Aboriginal investigators and collaborators.We report here baseline and longitudinal data on the factors associated with injection drug use and the transition to injection drug use to inform the development of prevention programs and policies.     

Cost-effectiveness of second-line antihyperglycemic therapy in patients with type 2 diabetes mellitus inadequately controlled on metformin

Background:

Metformin is widely accepted as first-line pharmacotherapy for patients with type 2 diabetes mellitus when glycemic control cannot be achieved by lifestyle interventions alone. However, uncertainty exists regarding the optimal second-line therapy for patients whose diabetes is inadequately controlled by metformin monotherapy. Increased use of newer, more costly agents, along with the rising incidence of type 2 diabetes, carries significant budgetary implications for health care systems. We conducted this analysis to determine the relative costs, benefits and cost-effectiveness of options for second-line treatment of type 2 diabetes.

Methods:

We used the United Kingdom Prospective Diabetes Study Outcomes Model to forecast diabetes-related complications, quality-adjusted life-years and costs of alternative second-line therapies available in Canada for adults with type 2 diabetes inadequately controlled by metformin. We obtained clinical data from a systematic review and mixed treatment comparison meta-analysis, and we obtained information on costs and utilities from published sources. We performed extensive sensitivity analyses to test the robustness of results to variation in inputs and assumptions.

Results:

Sulphonylureas, when added to metformin, were associated with the most favourable cost-effectiveness estimate, with an incremental cost of $12 757 per quality-adjusted life-year gained, relative to continued metformin monotherapy. Treatment with other agents, including thiazolidinediones and dipeptidyl peptidase-4 inhibitors, had unfavourable cost-effectiveness estimates compared with sulphonylureas. These results were robust to extensive sensitivity analyses.

Interpretation:

For most patients with type 2 diabetes that is inadequately controlled with metformin monotherapy, the addition of a sulphonylurea represents the most cost-effective second-line therapy.Type 2 diabetes mellitus is a progressive disease typically treated in a stepwise fashion, beginning with lifestyle modification, followed by the addition of one or more oral antihyperglycemic drugs and, finally, administration of exogenous insulin. Metformin monotherapy is widely recommended as first-line pharmacotherapy,^1,2 given its favourable effects in controlling blood glucose and body weight, low risk of hypoglycemia, low cost and association with mortality benefit.³ Multiple second-line treatment strategies are available for patients in whom glycemic control has become inadequate. These approaches are typically used in addition to continued metformin therapy.^4,5 Numerous second-line agents are available in Canada, including older oral agents, such as sulphonylureas, and more recently introduced agents, such as thiazolidinediones and dipeptidyl peptidase-4 inhibitors.The large number of choices for second-line therapy has increased uncertainty regarding the optimal treatment pathway. Recent clinical practice guidelines, including those produced by the Canadian Diabetes Association¹ and by the American Diabetes Association and the European Association for the Study of Diabetes,² have suggested selecting from among several agents on the basis of their respective advantages and disadvantages. There has been a considerable increase in the use of newer, more costly oral antihyperglycemic agents, which has resulted in substantial increases in associated costs to patients and both public and private drug plans in Canada.⁴ In light of current therapeutic uncertainty, the large proportion of patients requiring second-line therapy over time^3,6 and the increasing prevalence of type 2 diabetes,⁷ the utilization and cost of second-line therapy are likely to continue to grow.Informed decisions regarding optimal prescribing and reimbursement of second-line agents by public and private health care payers requires information about clinical benefits, costs and cost-effectiveness.⁸ As part of a larger initiative to determine optimal prescribing of antihyperglycemic agents, we sought to determine the incremental cost-effectiveness of treatment with alternative second-line agents added to metformin in patients with type 2 diabetes no longer adequately controlled by metformin monotherapy.     

Income-related differences in mortality among people with diabetes mellitus

Background

Mortality has declined substantially among people with diabetes mellitus over the last decade. Whether all income groups have benefited equally, however, is unclear. We examined the impact of income on mortality trends among people with diabetes.

Methods

In this population-based, retrospective cohort study, we compared changes in mortality from Apr. 1, 1994, to Mar. 31, 2005, by neighbourhood income strata among people with diabetes aged 30 years or more in the province of Ontario, Canada.

Results

Overall, the annual age- and sex-adjusted mortality declined, from 4.05% in 1994/95 (95% confidence interval [CI] 3.98%–4.11%) to 2.69% in 2005/06 (95% CI 2.66%–2.73%). The decrease was significantly greater in the highest income group (by 36%) than in the lowest income group (by 31%; p < 0.001). This trend was most pronounced in the younger group (age 30–64 years): the mortality rate ratio widened by more than 40% between the lowest and highest income groups, from 1.12 to 1.59 among women and from 1.14 to 1.60 among men. Income had a much smaller effect on mortality trends in the older group, whose drug costs are subsidized: the income-related difference rose by only 0.9% over the study period.

Interpretation

Mortality declined overall among people with diabetes from 1994 to 2005; however, the decrease was substantially greater in the highest income group than in the lowest, particularly among those aged 30–64 years. These findings illustrate the increasing impact of income on the health of people with diabetes even in a publicly funded health care setting. Further studies are needed to explore factors responsible for these income-related differences in mortality.The number of people with diabetes mellitus has increased dramatically over the last 20 years^1,2 and is estimated to double to about 366 million by 2030.³ Diabetes is associated with a 2-fold increase in mortality, with the majority of deaths attributed to cardiovascular causes.⁴ However, survival among people with diabetes has improved substantially over the last decade,^1,5,6 in part because of better diabetes care and a reduction in cardiovascular events.⁶Income is a well-known predictor of survival.^7,8 Even in Canada, where much of health care is universally funded, income-based inequities in health and access to care remain.^9–12 Although income-related differences in all-cause mortality have decreased since the advent of provincially subsidized health care in Canada,^8,9 the income gap may be increasing for certain causes of death, including those related to diabetes.⁸ The shift to more complex medical care involving a greater number of drug therapies has resulted in improved diabetes-related outcomes overall.¹³ However, patients in lower-income groups may not have benefited from advances in diabetes care as much as more affluent patients have because of the financial burden of out-of-pocket expenses for such medications and diabetes supplies.We conducted a population-based study to examine income-related differences in mortality from 1994 to 2005 among people with diabetes.     

Migration and health in Canada: health in the global village

Background:

Immigration has been and remains an important force shaping Canadian demography and identity. Health characteristics associated with the movement of large numbers of people have current and future implications for migrants, health practitioners and health systems. We aimed to identify demographics and health status data for migrant populations in Canada.

Methods:

We systematically searched Ovid MEDLINE (1996–2009) and other relevant web-based databases to examine immigrant selection processes, demographic statistics, health status from population studies and health service implications associated with migration to Canada. Studies and data were selected based on relevance, use of recent data and quality.

Results:

Currently, immigration represents two-thirds of Canada’s population growth, and immigrants make up more than 20% of the nation’s population. Both of these metrics are expected to increase. In general, newly arriving immigrants are healthier than the Canadian population, but over time there is a decline in this healthy immigrant effect. Immigrants and children born to new immigrants represent growing cohorts; in some metropolitan regions of Canada, they represent the majority of the patient population. Access to health services and health conditions of some migrant populations differ from patterns among Canadian-born patients, and these disparities have implications for preventive care and provision of health services.

Interpretation:

Because the health characteristics of some migrant populations vary according to their origin and experience, improved understanding of the scope and nature of the immigration process will help practitioners who will be increasingly involved in the care of immigrant populations, including prevention, early detection of disease and treatment.Migration is an important component of globalization. International migration is estimated at 200 million people,¹ and the volume of migration continues to increase. Between 1990 and 2005, global migrants increased by some 33 million people, with the largest growth observed in the developed world. The movement of populations of this size has important implications for health practitioners, health systems² and the health of individuals.^3,4Health status is associated with quality of life and use of formal and informal health services.⁵ Overall, immigrants appear to be healthier than the Canadian-born population, by virtue of being capable, both physically and mentally, of successfully moving themselves, and often their families, from one country to another.⁶ However, over time, this healthy immigrant effect is lost.⁷Health status is not equivalent across all subgroups of immigrants. Certain migrant populations experience a higher risk of infectious diseases, cancer, diabetes and heart disease, which has clinical implications for those providing care to migrant communities.⁶ The health of migrants is a product of environmental, economic, genetic and socio-cultural factors related to when people migrated to Canada, where and how they lived in their original home country, and how and why they migrated. Their health is also influenced by postmigration factors involving integration into their new place of residence, employment, education and poverty, as well as the accessibility and responsiveness of health practitioners and responsiveness of the Canadian health care system to immigrants’ health needs.⁸Migration medicine is complicated by the use of similar terms, such as immigrant, refugee or migrant, for what are, in reality, different populations. This article will use standard Canadian immigration terminology. To help primary care practitioners interpret the clinical preventive recommendations of the Canadian Collaboration for Immigrant and Refugee Health, we aimed to identify demographics, health status reports, access to health care and health system implications of migrant populations in Canada.     

Adverse outcomes among Aboriginal patients receiving peritoneal dialysis

Background

The Aboriginal population in Canada experiences high rates of end-stage renal disease and need for dialytic therapies. Our objective was to examine rates of mortality, technique failure and peritonitis among adult aboriginal patients receiving peritoneal dialysis in the province of Manitoba. We also aimed to explore whether differences in these rates may be accounted for by location of residence (i.e., urban versus rural).

Methods

We included all adult patients residing in the province of Manitoba who received peritoneal dialysis during the period from 1997–2007 (n = 727). We extracted data from a local administrative database and from the Canadian Organ Replacement Registry and the Peritonitis Organism Exit-sites/Tunnel infections (POET) database. We used Cox and logistic regression models to determine the relationship between outcomes and Aboriginal ethnicity. We performed Kaplan–Meier analyses to examine the relationship between outcomes and urban (i.e., 50 km or less from the primary dialysis centre in Winnipeg) versus rural (i.e., more than 50 km from the centre) residency among patients who were aboriginal.

Results

One hundred sixty-one Aboriginal and 566 non-Aboriginal patients were included in the analyses. Adjusted hazard ratios for mortality (HR 1.476, CI 1.073–2.030) and adjusted time to peritonitis (HR 1.785, CI 1.352–2.357) were significantly higher among Aboriginal patients than among non-Aboriginal patients. We found no significant differences in mortality, technique failure or peritonitis between urban- or rural-residing Aboriginal patients.

Interpretation

Compared with non-Aboriginal patients receiving peritoneal dialysis, Aboriginal patients receiving peritoneal dialysis had higher mortality and faster time to peritonitis independent of comorbidities and demographic characteristics. This effect was not influenced by place of residence, whether rural or urban.The Canadian Aboriginal population suffers from a high burden of illness,^1,2 low socio-economic status and geographic isolation.³ A high prevalence of diabetes mellitus, obesity and hypertension in this population is resulting in rapid growth in rates of kidney disease and renal failure (i.e., end-stage renal disease).^4–6 The escalation in demand for dialytic services and care of patients with end-stage renal disease care will require appropriate planning and allocation of health care resources.Hemodialysis is resource-intensive and requires residence in proximity to a dialysis centre. In Canada, roughly 18% of all dialysis patients are receiving peritoneal dialysis.⁷ These patients are responsible for their own dialysis therapy and are seen periodically in an ambulatory clinic setting. No clear mortality-related benefit is associated with choice in modality of dialysis; each method has its own risks and benefits.^8–10 Complications of peritoneal dialysis include technique failure, which often requires conversion to hemodialysis and relocation of the patient, and peritonitis.Dosage of peritoneal dialysis is determined by the combined clearance of solutes from the peritoneum (termed the peritoneal Kt/V) and, if applicable, by residual renal function (termed renal Kt/V). The peritoneal equilibration test is a marker of the peritoneal membranes solute transport characteristics and high peritoneal equilibration test values have been associated with inflammation, volume overload, technique failure and mortality.¹¹Compared with non-Aboriginal patients who have end-stage renal disease, Aboriginal patients with end-stage renal disease are younger on average and more likely to reside in geographically remote locations.¹² Use of home-based dialysis modalities, such as peritoneal dialysis, would be well suited to this population because it allows patients to continue to live in their communities. However, residing far from a dialysis centre or a patient’s primary nephrologist is associated with increased mortality, poor compliance and impaired quality of life.^12,13 Previous studies have found that Aboriginal patients receiving peritoneal dialysis have similar mortality and rates of technique failure to patients of other ethnicities. But whether this is true in a contemporary cohort is not known.^14,15Our objective was to examine differences in mortality and in rates of technique failure and peritonitis among Aboriginal patients versus non-Aboriginal patients receiving peritoneal dialysis and to explore whether differences may be accounted for by urban versus rural residence.     

The responses of Aboriginal Canadians to adjuvanted pandemic (H1N1) 2009 influenza vaccine

Background:

Because many Aboriginal Canadians had severe cases of pandemic (H1N1) 2009 influenza, they were given priority access to vaccine. However, it was not known if the single recommended dose would adequately protect people at high risk, prompting our study to assess responses to the vaccine among Aboriginal Canadians.

Methods:

We enrolled First Nations and Métis adults aged 20–59 years in our prospective cohort study. Participants were given one 0.5-mL dose of ASO3-adjuvanted pandemic (H1N1) 2009 vaccine (Arepanrix, GlaxoSmithKline Canada). Blood samples were taken at baseline and 21–28 days after vaccination. Paired sera were tested for hemagglutination-inhibiting antibodies at a reference laboratory. To assess vaccine safety, we monitored the injection site symptoms of each participant for seven days. We also monitored patients for general symptoms within 7 days of vaccination and any use of the health care system for 21–28 days after vaccination.

Results:

We enrolled 138 participants in the study (95 First Nations, 43 Métis), 137 of whom provided all safety data and 136 of whom provided both blood samples. First Nations and Métis participants had similar characteristics, including high rates of chronic health conditions (74.4%–76.8%). Pre-existing antibody to the virus was detected in 34.3% of the participants, all of whom boosted strongly with vaccination (seroprotection rate [titre ≥ 40] 100%, geometric mean titre 531–667). Particpants with no pre-existing antibody also responded well. Fifty-eight of 59 (98.3%) First Nations participants showed seroprotection and a geometric mean titre of 353.6; all 30 Métis participants with no pre-existing antibody showed seroprotection and a geometric mean titre of 376.2. Pain at the injection site and general symptoms frequently occurred but were short-lived and generally not severe, although three participants (2.2%) sought medical attention for general symptoms.

Interpretation:

First Nations and Métis adults responded robustly to ASO3-adjuvanted pandemic (H1N1) 2009 vaccine. Virtually all participants showed protective titres, including those with chronic health conditions.

Trial registration:

ClinicalTrials.gov trial register no. NCT.01001026.During the first wave of the H1N1 pandemic in Canada in 2009, some First Nations communities were severely affected, with younger adults and children most at risk for severe disease.^1,2 Whereas Aboriginal Canadians make up 3.4% of the population (with 1.14 million people), they accounted for 16% of admissions to hospital during the first wave of the pandemic, and 43% of Aboriginal patients had underlying medical conditions.³ The increased rate of severe disease might have resulted from residential crowding, prevalence of chronic health conditions, delayed access to health care or suboptimal immune responses to infection.⁴ When a federally funded, ASO3-adjuvanted (squalene/tocopherol) pandemic vaccine became available for Canadians later in 2009,⁵ Aboriginal people were given priority access to it.³ However, dosing requirements at the time were tentative. Previous studies of an ASO3-adjuvanted influenza A (H5N1) vaccine established that two doses were needed for immunity in adults.⁶ Because the 2009 influenza (H1N1) pandemic occurred without warning, no prepandemic studies had been done with vaccines based on this novel swine-derived virus.⁷The ASO3-adjuvanted pandemic (H1N1) 2009 vaccine manufactured in Canada (Arepanrix, GlaxoSmithKline, Laval, Quebec) was released for public use as soon as it was available, unstudied, to mitigate morbidity during the pandemic’s second wave, which was already in progress. A single 3.75-μg dose of hemagglutinin was recommended for adults using the preliminary results of a European trial of another ASO3-adjuvanted vaccine (Pandemrix, GlaxoSmithKline, Rixensart, Belgium) given to 65 adults aged 18–60 years.⁸ The European product was believed to be equivalent to the Canadian-made vaccine, but this had not yet been shown.We wondered if the recommended single dose would be adequate for Aboriginal Canadian adults given their heightened risk of severe influenza during the first wave. We were unable to identify any previous studies of influenza vaccines involving Aboriginal Canadians to determine if their responses would be similar to other Canadians or to the healthy European study participants on whom the dosing recommendation was based. Consequently, we undertook a study involving First Nations and Métis adults to assess their responses to the pandemic vaccine.     

Unintended consequences of delisting routine eye exams on retinopathy screening for people with diabetes in Ontario,Canada

Background:

Routine eye examinations for healthy adults aged 20–64 years were delisted from the Ontario Health Insurance Plan in 2004, but they continue to be insured for people with diabetes regardless of age. We sought to assess whether the delisting of routine eye examinations for healthy adults had the unintended consequence of decreasing retinopathy screening for adults with diabetes.

Methods:

We used administrative data to calculate eye examinations for people with diabetes ages 40–64 years and 65 years and older in each 2-year period from 1998 to 2010. We examined differences by sex, income, rurality and type of health care provider. We used segmented linear regression to assess the change in trend before and after 2004.

Results:

For people with diabetes aged 65 years and older, eye examinations rose gradually from 1998 to 2010, with no substantial change between 2004 and 2006. For people with diabetes aged 40–65 years, there was an 8.7% (95% confidence interval [CI] 6.3%–11.1%) decrease in eye examinations between 2004 and 2006. Results were similar for all population subgroups. Ophthalmologic examinations decreased steadily for both age groups during the study period, and there was a decline in optometry examinations for people ages 40–65 years after 2004.

Interpretation:

The delisting of routine eye examinations for healthy adults in Ontario had the unintended consequence of reducing publicly funded retinopathy screening for people with diabetes. More research is needed to understand whether patients are being charged for an insured service or to what degree misunderstanding has prevented patients from seeking care.Diabetic retinopathy is the leading cause of new cases of blindness in people of working age.¹ In the United States, about 40% of adults with diabetes aged 40 years and older have retinopathy, and 8% have vision-threatening retinopathy.² Studies suggest that, if untreated, 50% of patients with proliferative diabetic retinopathy become legally blind within 5 years, compared with only 5% of patients who receive early treatment.³ Regular dilated eye examinations are effective for early detection and monitoring of asymptomatic retinopathy in people with diabetes⁴ and are recommended by clinical practice guidelines.^5,6In Ontario, Canada’s most populous province, medically necessary services are covered by the Ontario Health Insurance Plan (OHIP) for all permanent residents and Canadian citizens living in the province.⁷ Under OHIP, routine eye examinations were fully insured for all children and adults until November 1, 2004. At that time, routine eye examinations ceased being insured for healthy adults aged 20–64 years, but continued to be insured for children aged 19 years and younger and for adults aged 65 years and older.⁸ Regardless of age, adults with diabetes and some other medical conditions affecting the eye, as well as adults receiving social assistance, continued to have an annual eye examination covered by OHIP. Insured examinations are at no cost to the patient and are reimbursed to the provider at about Can$40. In contrast, healthy adults aged 20–64 years are required to pay out-of-pocket or through private insurance for a routine eye examination, with fees set at the discretion of the optometrist⁹ or physician.¹⁰Health policy experts suggest that delisting services from insurance schemes can have unpredictable effects.¹¹ Understanding the effect of delisting on care is particularly important as governments face fiscal pressures and contemplate further reductions in what is publicly insured.¹² We sought to assess whether delisting routine eye examinations for healthy middle-aged adults in Ontario had the unintended consequence of decreasing retinopathy screening for middle-aged adults with diabetes, even though eye examinations continued to be insured for this population.     

Body mass index and all-cause mortality in a large Chinese cohort

Background

Obesity is known to be associated with an increased risk of death, but current definitions of obesity are based on data from white populations. We examined the association between body mass index (BMI) and the risk of death in a large population of adult Chinese people.

Methods

We examined the association between body mass index (BMI) and all-cause mortality prospectively among 58 738 men and 65 718 women aged 20 years and older enrolled in 1998–1999 from four national health screening centres in Taiwan. We used Cox proportional hazards regression analyses to estimate the relative risks of all-cause mortality for different BMI categories during a maximum follow-up of 10 years.

Results

A total of 3947 participants died during the follow-up period. The lowest risk of death was observed among men and women who had a BMI of 24.0–25.9 (mean 24.9). After adjustment for age, smoking status, alcohol intake, betel-nut chewing, level of physical activity, income level and education level, we observed a U-shaped association between BMI and all-cause mortality. Similar U-shaped associations were observed when we analyzed data by age (20–64 or ≥ 65 years), smoking (never, < 10 pack-years or ≥ 10 pack-years) and presence of a pre-existing chronic disease, and after we excluded deaths that occurred in the first three years of follow-up.

Interpretation

BMI and all-cause mortality had a U-shaped association among adult Chinese people in our study. The lowest risk of death was among adults who had a BMI of 24.0–25.9 (mean 24.9). Our findings do not support the use of a lower cutoff value for overweight and obesity in the adult Chinese population.The prevalence of obesity has dramatically increased in past decades in both developed and developing countries. The World Health Organization (WHO) reported that 1.6 billion adults are overweight and at least 400 million are obese.¹ The WHO further predicted that by the year 2015, about 2.3 billion adults will be overweight and more than 700 million will be obese.¹ In Taiwan, according to a national survey performed between 1993–1996 and 2005–2008, the prevalence of overweight and obesity (defined as body mass index [BMI] ≥ 24 kg/m²) had increased dramatically, from 33.4% to 50.8% among men and from 31.7% to 36.9% among women.²Overweight and obesity have been recognized as important and independent risk factors for many chronic diseases such as diabetes mellitus, hypertension, stroke, cardiovascular diseases and malignant diseases.^3–7 Substantial epidemiologic evidence shows that obesity is associated with an increased risk of cardiovascular-related and all-cause mortality.^8,9 Therefore, obesity has become a major public health problem around the world.Current definitions of obesity and overweight in adults are based on data from white populations. The WHO has proposed another definition for Asian people, but most of the data it used were from cross-sectional studies.¹⁰ One study showed that, for a given BMI, Asian people had higher body fat than white people.¹¹ Furthermore, the association between BMI and all-cause mortality has been reported to be J-shaped or U-shaped. Most of the studies involved white people, with only a few involving Asian populations. Gu and colleagues reported a U-shaped association between BMI and all-cause mortality among Chinese people.¹² However, they included only middle-aged adults over 40 years old and not all adults over 20 years.We designed a large prospective cohort study to assess the association between BMI and all-cause mortality in a nationwide representative sample of Chinese adults over 20 years old in Taiwan. We also intended to find the optimal BMI cutoff values for overweight and obesity among Chinese adults.     

Prevalence of metabolic syndrome in the Canadian adult population

Background:

Metabolic syndrome refers to a constellation of conditions that increases a person’s risk of diabetes and cardiovascular disease. We describe the prevalence of metabolic syndrome and its components in relation to sociodemographic factors in the Canadian adult population.

Methods:

We used data from cycle 1 of the Canadian Health Measures Survey, a cross-sectional survey of a representative sample of the population. We included data for respondents aged 18 years and older for whom fasting blood samples were available; pregnant women were excluded. We calculated weighted estimates of the prevalence of metabolic syndrome and its components in relation to age, sex, education level and income.

Results:

The estimated prevalence of metabolic syndrome was 19.1%. Age was the strongest predictor of the syndrome: 17.0% of participants 18–39 years old had metabolic syndrome, as compared with 39.0% of those 70–79 years. Abdominal obesity was the most common component of the syndrome (35.0%) and was more prevalent among women than among men (40.0% v. 29.1%; p = 0.013). Men were more likely than women to have an elevated fasting glucose level (18.9% v. 13.6%; p = 0.025) and hypertriglyceridemia (29.0% v. 20.0%; p = 0.012). The prevalence of metabolic syndrome was higher among people in households with lower education and income levels.

Interpretation:

About one in five Canadian adults had metabolic syndrome. People at increased risk were those in households with lower education and income levels. The burden of abdominal obesity, low HDL (high-density lipoprotein) cholesterol and hypertriglyceridemia among young people was especially of concern, because the risk of cardiovascular disease increases with age.Chronic disease contributes significantly to morbidity and mortality in the Canadian population.¹ As such, the economic costs are substantial. Metabolic syndrome refers to a constellation of conditions that approximately doubles a person’s risk of cardiovascular disease, independently of other risk factors.^2–5 The cause of metabolic syndrome has not been fully elucidated; a summary of the current proposed mechanisms is discussed elsewhere.⁶Several sets of criteria have been established for the detection of metabolic syndrome, many of which have been continually updated.^6–8 The set of criteria most commonly used in the past was published in the third report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III criteria).⁹ Recently, the International Diabetes Federation, the American Heart Association, the National Heart, Lung, and Blood Institute, and other organizations collaborated to release a unified set of criteria.¹⁰The Canadian Health Measures Survey, conducted in 2007–2009, was the first cross-sectional survey of a representative sample of Canadians that collected biological samples since the Canadian Heart Health Surveys about 20 years ago.¹¹ We used data from the Canadian Health Measures Survey to describe the prevalence of metabolic syndrome and its components by age, sex, education level and income adequacy in a sample of the Canadian adult population. Because different studies have used various criteria in the past to define metabolic syndrome, and because there is continuing controversy as to the appropriate criteria, we calculated the prevalence according to several types of criteria to better facilitate comparison to findings from past and future studies.     

A population-based profile of adult Canadians living with participation and activity limitations

Background:

Currently, one out of every seven Canadians is affected by limitations to their participation and activity. This study describes the self-reported main causes of these limitations in a national sample.

Methods:

The 2006 Participation and Activity Limitation Survey was a two-phase stratified survey based on filter questions posed in the 2006 Census of Population conducted by Statistics Canada. Respondents to the survey represent 5 185 980 Canadian adults with activity and participation limitations. We used these data to develop a profile of our population of interest: adult Canadians with activity and participation limitations. Associations between demographic variables and self-reported causes of activity and participation limitations were assessed using multiple logistic regression.

Results:

One quarter of participants did not attribute their disability to any medical cause. The most prevalent medical conditions to which disabilities were attributed were musculoskeletal (46.1%), cardio/cerebrovascular (12.3%), mental health (8.4%), neurologic (6.0%), endocrine (6.0%) and respiratory (4.5%) conditions. Significant associations were noted between sociodemographic variables and participants’ attributions of medical conditions as cause of disability. Multiple logistic regression with bootstrapping showed that people who reported a medical cause for their limitation were more likely (p < 0.05) to be female, widowed, 40 years of age or older, born in Canada or white and were less likely (p < 0.05) to be in the highest income category or to be employed (i.e., to work more than 0 h/w).

Interpretation:

Most people living with activity and participation limitations report having a musculoskeletal disorder. However, a significant proportion of respondants did not attribute their limitations to a medical cause.Disabilities affect close to five million, or one in seven, Canadians.¹ Between 2001 and 2006, the number of Canadians living with a disability increased by 21.2%, rising from 12.4% to 14.3% of the population.¹ Given that the number of adults reporting a disability is expected to continue to rise sharply in the coming years as more people enter the highest-risk age group (≥ 65 yr), the concomitant need for additional and appropriate disability-related health services will exert greater pressure on health care systems.² Data on disabilities are increasingly used to monitor and evaluate public health as a reflection of the burden of health problems in relation to chronic diseases and aging³ and to identify the resources needed to ameliorate the impact of disabilities.⁴“Disablement” was coined by Verbrugge and Jette in 1994⁵ to refer to the impacts that chronic and acute conditions have on the functioning of specific body systems and on people’s abilities to act in necessary, usual, expected and personally desired ways in society. In 2002, the World Health Organization (WHO) took a broader view, defining disability from a biopsychosocial perspective as the interaction between features of the person and features of the context in which he or she lives.⁴ Disability is conceptualized to involve dysfunction at the level of body functions or structures, limitations to activity or restrictions on participation. The International Classification of Functioning, Disability and Health,⁴ is based on an integrated biopsychosocial model and incorporates the following elements under activities and participation: learning and applying knowledge; general tasks and demands; communication; mobility; self care; domestic life; interpersonal interactions and relationships; major life areas; and community, social and civic life. Statistics Canada^5,6 views disability as an activity limitation or participation restriction associated with long-term physical or mental conditions or health-related conditions. The Statistics Canada definition also incorporates all of the elements listed in the International Classification of Functioning, Disability and Health.⁶There have been substantial efforts to fight the automatic identification of disability with illness and to frame disability as a purely social construct.^6–8 However, many people have participation and activity limitations as a result of chronic illnesses. In addition, many people with participation and activity limitations not caused by illnesses have chronic health problems as a direct result of their restrictions.⁹ Whether a person attributes his or her disability to a medical diagnosis or to another cause has implications for that person’s adherence to treatment, self-management and care-seeking behaviours¹⁰.Using a validated national sample, this survey study describes the types of medical conditions reported by adult Canadians living with participation and activity limitations.     

Cost-effectiveness of the use of low- and high-potency statins in people at low cardiovascular risk

Background:

Although statins have been shown to reduce the risk of cardiovascular events in patients at low cardiovascular risk, their absolute benefit is small in the short term, which may adversely affect cost-effectiveness. We sought to determine the long-term cost-effectiveness (beyond the duration of clinical trials) of low- and high-potency statins in patients at low cardiovascular risk and to estimate the impact on Canada’s publicly funded health care system.

Methods:

Using Markov modelling, we performed a cost-utility analysis in which we compared low-potency statins (fluvastatin, lovastatin, pravastatin and simvastatin) and high-potency statins (atorvastatin and rosuvastatin) with no statins in a simulated cohort of low-risk patients over a lifetime horizon. Model outcomes included costs (in 2010 Canadian dollars), quality-adjusted life-years (QALYs) gained and the cost per QALY gained.

Results:

Over a lifetime horizon, the cost of managing a patient at low cardiovascular risk was estimated to be about $10 100 without statins, $15 200 with low-potency statins and $16 400 with high-potency statins. The cost per QALY gained with high-potency statins (v. no statins) was $21 300; the use of low-potency statins was not considered economically attractive. These results were robust to sensitivity analyses, although their use became economically unattractive when the duration of benefit from statin use was assumed to be less than 10 years.

Interpretation:

Use of high-potency statins in patients at low cardiovascular risk was associated with a cost per QALY gained that was economically attractive by current standards, assuming that the benefit from statin use would continue for at least 10 years. However, the overall expenditure on statins would be substantial, and the ramifications of this practice should be carefully considered by policy-makers.Although statins improve survival and reduce the risk of cardiovascular events in populations at high and moderate risk,¹ their effectiveness and cost-effectiveness in low-risk populations is less certain.² This uncertainly is due in part to low-risk patients being less likely to have cardiovascular events over the short term. For instance, in the recent Justification for the Use of Statins in Prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER) study³ — a large randomized trial comparing cardiovascular outcomes in low-risk patients randomly assigned to receive either rosuvastatin or placebo — the risk of death or nonfatal myocardial infarction over three years was 2.5% in the rosuvastatin group and 3.5% in the placebo group, which represented a large relative, but small absolute, risk reduction in cardiovascular events.Other cholesterol-lowering interventions are available, such as diet, exercise and the use of other hypolipidemic agents, but the use of statins is the only such intervention known to reduce cardiovascular risk in people with low and high blood cholesterol levels.^4–7 Thus, statins are now primarily indicated for the reduction of cardiovascular risk instead of being used mainly for the management of hypercholesterolemia.⁸With this broadening indication for use, expenditures on statins have increased and represent about 13% of total expenditures by provincial formularies in Canada.⁹ The absolute number of people at low cardiovascular risk who are taking statins has increased substantially over the last decade, driven by the large number of low-risk people in the general population.¹⁰ In addition, statins that are more effective in lowering low-density lipoprotein (LDL) cholesterol levels have become available.^3,11 These high-potency statins (atorvastatin and rosuvastatin) are substantially more expensive than low-potency statins available as generics (pravastatin, simvastatin, fluvastatin and lovastatin), although atorvastatin has recently become available as a generic in Canada.¹² Increasing costs and concerns over the absolute benefit of statins in people at low cardiovascular risk has raised concerns about the cost-effectiveness of statins in this group.We performed an incremental cost-utility analysis comparing low- and high-potency statins with no statins in patients at low cardiovascular risk in a Canadian setting. We used findings from our group’s recent systematic review of the efficacy of statins for primary prevention in low-risk people¹³ as well as observational data from a large provincial registry of patients documenting existing statin use. Our objective was to determine which strategy represents the best use of health care resources for the publicly funded health care system, and what investment would be required to fund statins.