Geographic concentration of SARS-CoV-2 cases by social determinants of health in metropolitan areas in Canada: a cross-sectional study

Background:Understanding inequalities in SARS-CoV-2 transmission associated with the social determinants of health could help the development of effective mitigation strategies that are responsive to local transmission dynamics. This study aims to quantify social determinants of geographic concentration of SARS-CoV-2 cases across 16 census metropolitan areas (hereafter, cities) in 4 Canadian provinces, British Columbia, Manitoba, Ontario and Quebec.Methods:We used surveillance data on confirmed SARS-CoV-2 cases and census data for social determinants at the level of the dissemination area (DA). We calculated Gini coefficients to determine the overall geographic heterogeneity of confirmed cases of SARS-CoV-2 in each city, and calculated Gini covariance coefficients to determine each city’s heterogeneity by each social determinant (income, education, housing density and proportions of visible minorities, recent immigrants and essential workers). We visualized heterogeneity using Lorenz (concentration) curves.Results:We observed geographic concentration of SARS-CoV-2 cases in cities, as half of the cumulative cases were concentrated in DAs containing 21%–35% of their population, with the greatest geographic heterogeneity in Ontario cities (Gini coefficients 0.32–0.47), followed by British Columbia (0.23–0.36), Manitoba (0.32) and Quebec (0.28–0.37). Cases were disproportionately concentrated in areas with lower income and educational attainment, and in areas with a higher proportion of visible minorities, recent immigrants, high-density housing and essential workers. Although a consistent feature across cities was concentration by the proportion of visible minorities, the magnitude of concentration by social determinant varied across cities.Interpretation:Geographic concentration of SARS-CoV-2 cases was observed in all of the included cities, but the pattern by social determinants varied. Geographically prioritized allocation of resources and services should be tailored to the local drivers of inequalities in transmission in response to the resurgence of SARS-CoV-2.

The COVID-19 epidemic in Canada has varied in size and trajectory across provinces and large cities.^1,2 At the national level³ and within regions,^4,5 the burden of confirmed SARS-CoV-2 cases and severe COVID-19 outcomes has fallen disproportionately on socially and economically marginalized communities. ⁶ Social determinants of health refer to nonmedical factors influencing health outcomes, and structural determinants encompass cultural norms, policies and institutions that generate social stratification and determine socioeconomic position.^7,8 In Canada and elsewhere, data have consistently highlighted the importance of determinants such as household size and density, work in essential services and structural racism (measured by proxy) in the relative risk of COVID-19.^9–17Understanding the factors associated with geographic patterns of transmission within cities can help identify the populations and, specifically, the contexts with the greatest risks. Geographic analyses can enable better allocation of resources, tailoring of policies and implementation of context-specific strategies to more effectively and efficiently curb local transmission. ¹⁸ Although respiratory virus transmission is often geographically clustered within a city,¹⁹ the early public health response to SARS-CoV-2 transmission in Canada did little to take within-city clustering into account.^20,21 Similarly, few studies have quantified and compared the geographic concentration of SARS-CoV-2 cases by social determinants across Canada, and the extent to which the magnitude of inequalities might vary among cities and provinces.^19,22 We therefore sought to quantify and compare the magnitude of geographic concentration of SARS-CoV-2 cases by area-level social determinants of health across metropolitan areas in British Columbia, Manitoba, Ontario and Quebec, Canada.     

Rates of stillbirth by gestational age and cause in Inuit and First Nations populations in Quebec

Background:

Inuit and First Nations populations have higher rates of stillbirth than non-Aboriginal populations in Canada do, but little is known about the timing and cause of stillbirth in Aboriginal populations. We compared gestational age– and cause-specific stillbirth rates in Inuit and First Nations populations with the rates in the non-Aboriginal population in Quebec.

Methods:

Data included singleton stillbirths and live births at 24 or more gestational weeks among Quebec residents from 1981 to 2009. We calculated odds ratios (ORs), rate differences and 95% confidence intervals (CIs) for the retrospective cohort of Inuit and First Nations births relative to non-Aboriginal births using fetuses at risk (i.e., ongoing pregnancies) as denominators and adjusting for maternal characteristics. The main outcomes were stillbirth by gestational age (24–27, 28–36, ≥ 37 wk) and cause of death.

Results:

Rates of stillbirth per 1000 births were greater among Inuit (6.8) and First Nations (5.7) than among non-Aboriginal (3.6) residents. Relative to the non-Aboriginal population, the risk of stillbirth was greater at term (≥ 37 wk) than before term for both Inuit (OR 3.1, 95% CI 1.9 to 4.8) and First Nations (OR 2.6, 95% CI 2.1 to 3.3) populations. Causes most strongly associated with stillbirth were poor fetal growth, placental disorders and congenital anomalies among the Inuit, and hypertension and diabetes among the First Nations residents.

Interpretation:

Stillbirth rates in Aboriginal populations were particularly high at term gestation. Poor fetal growth, placental disorders and congenital anomalies were important causes of stillbirth among the Inuit, and diabetic and hypertensive complications were important causes in the First Nations population. Prevention may require improvements in pregnancy and obstetric care.Attention has recently been drawn to the paucity of data on rates and causes of stillbirth, a pregnancy outcome that is largely ignored compared with later deaths.¹ Aboriginal populations in Canada rank at the top of the list of disadvantaged groups with the highest rates of stillbirth in the Western world.¹ First Nations and Inuit, 2 distinct Aboriginal populations in Canada, have stillbirth rates that are 2–3 times that among non-Aboriginal Canadians.^1,2 Although these trends are alarming, little data exist to guide prevention efforts among Aboriginal Canadians. Not much is known about how stillbirth rates in Aboriginal populations vary by gestational age or cause of death, despite evidence that prevention requires knowledge on the timing and cause of stillbirth.³ Opportunities for preventing stillbirth are typically greater after 28 weeks of gestation,⁴ particularly at term, but the absence of gestational age– and cause-specific comparisons between Aboriginal and non-Aboriginal Canadians is a major impediment to reducing stillbirth rates. To gain a better understanding of the timing and causes of stillbirth in Inuit and First Nations populations, we estimated gestational age– and cause-specific fetal death rates in the Aboriginal and non-Aboriginal populations in the province of Quebec, where Inuit and First Nations people can be identified by parental information on birth registration forms.     

Association between long-term exposure to ambient air pollution and COVID-19 severity: a prospective cohort study

Background:The tremendous global health burden related to COVID-19 means that identifying determinants of COVID-19 severity is important for prevention and intervention. We aimed to explore long-term exposure to ambient air pollution as a potential contributor to COVID-19 severity, given its known impact on the respiratory system.Methods:We used a cohort of all people with confirmed SARS-CoV-2 infection, aged 20 years and older and not residing in a long-term care facility in Ontario, Canada, during 2020. We evaluated the association between long-term exposure to fine particulate matter (PM_2.5), nitrogen dioxide (NO₂) and ground-level ozone (O₃), and risk of COVID-19-related hospital admission, intensive care unit (ICU) admission and death. We ascertained individuals’ long-term exposures to each air pollutant based on their residence from 2015 to 2019. We used logistic regression and adjusted for confounders and selection bias using various individual and contextual covariates obtained through data linkage.Results:Among the 151 105 people with confirmed SARS-CoV-2 infection in Ontario in 2020, we observed 8630 hospital admissions, 1912 ICU admissions and 2137 deaths related to COVID-19. For each interquartile range increase in exposure to PM_2.5 (1.70 μg/m³), we estimated odds ratios of 1.06 (95% confidence interval [CI] 1.01–1.12), 1.09 (95% CI 0.98–1.21) and 1.00 (95% CI 0.90–1.11) for hospital admission, ICU admission and death, respectively. Estimates were smaller for NO₂. We also estimated odds ratios of 1.15 (95% CI 1.06–1.23), 1.30 (95% CI 1.12–1.50) and 1.18 (95% CI 1.02–1.36) per interquartile range increase of 5.14 ppb in O₃ for hospital admission, ICU admission and death, respectively.Interpretation:Chronic exposure to air pollution may contribute to severe outcomes after SARS-CoV-2 infection, particularly exposure to O₃.

By November 2021, COVID-19 had caused more than 5 million deaths globally¹ and more than 29 400 in Canada.² The clinical manifestations of SARS-CoV-2 infection range from being asymptomatic to multiple organ failure and death. Identifying risk factors for COVID-19 severity is important to better understand etiological mechanisms and identify populations to prioritize for screening, vaccination and medical treatment. Risk factors for severity of COVID-19 include male sex, older age, pre-existing medical conditions and being from racialized communities.^3–5 More recently, ambient air pollution has been implicated as a potential driver of COVID-19 severity.^6–10Long-term exposure to ambient air pollution, a major contributor to global disease burden,¹¹ could increase the risk of severe COVID-19 outcomes by several mechanisms. Air pollutants can reduce individuals’ pulmonary immune responses and antimicrobial activities, boosting viral loads.⁸ Air pollution can also induce chronic inflammation and overexpression of the alveolar angiotensin-converting enzyme 2 (ACE) receptor,⁷ the key receptor that facilitates SARS-CoV-2 entry into cells.^12,13 Exposure to air pollution contributes to chronic conditions, such as cardiovascular disease, that are associated with unfavourable COVID-19 prognosis, possibly owing to persistent immune activation and excessive amplification of cytokine development.¹⁰ Thus, greater exposure to long-term air pollution may lead to severe COVID-19 outcomes.Reports exist of positive associations between long-term exposure to particulate matter with diameters equal to or smaller than 2.5 or 10 μm (PM_2.5 and PM₁₀), ground-level ozone (O₃) and nitrogen dioxide (NO₂), and metrics of COVID-19 severity (e.g., mortality and case fatality rate).^8–10 However, most studies to date have used ecological and cross-sectional designs, owing to limited access to individual data, which leads to ambiguity in interpreting the results, thus hindering their influence on policy. ^6,14 Ecological designs do not allow for disentangling the relative impacts of air pollution on individual susceptibility to infection and disease severity.¹⁴ Residual confounding by factors such as population mobility and social interactions is also problematic. Therefore, a cohort study with data on individuals with SARS-CoV-2 is a more appropriate design.^6,14 Studies that have used individual data were conducted in specific subpopulations^15,16 or populations with few severe cases,¹⁷ or had limited data on individual exposure to air pollutants.¹⁸ In Canada, 1 ecological study found a positive association between long-term exposure to PM_2.5 and COVID-19 incidence,¹⁹ but no published study has explored the association between air pollution and COVID-19 severity.We aimed to examine the associations between long-term exposure to 3 common air pollutants (PM_2.5, NO₂ and O₃) and key indicators of COVID-19 severity, including hospital admission, intensive care unit (ICU) admission and death, using a large prospective cohort of people with confirmed SARS-CoV-2 infection in Ontario, Canada, in 2020. The air contaminants PM_2.5, NO₂ and O₃ are regularly monitored by the Canadian government, and are key pollutants that are considered when setting air-quality policies. They originate from varying sources (NO₂ is primarily emitted during combustion of fuel, O₃ is primarily formed in air by chemical reactions of nitrogen oxides and volatile organic compounds, and PM_2.5 can be emitted during combustion or formed by reactions of chemicals like sulphur dioxide and nitrogen oxides in air) and they may affect human health differently.^20,21,22     

Impact of population mixing between vaccinated and unvaccinated subpopulations on infectious disease dynamics: implications for SARS-CoV-2 transmission

Background:The speed of vaccine development has been a singular achievement during the COVID-19 pandemic, although uptake has not been universal. Vaccine opponents often frame their opposition in terms of the rights of the unvaccinated. We sought to explore the impact of mixing of vaccinated and unvaccinated populations on risk of SARS-CoV-2 infection among vaccinated people.Methods:We constructed a simple susceptible–infectious–recovered compartmental model of a respiratory infectious disease with 2 connected subpopulations: people who were vaccinated and those who were unvaccinated. We simulated a spectrum of patterns of mixing between vaccinated and unvaccinated groups that ranged from random mixing to complete like-with-like mixing (complete assortativity), in which people have contact exclusively with others with the same vaccination status. We evaluated the dynamics of an epidemic within each subgroup and in the population as a whole.Results:We found that the risk of infection was markedly higher among unvaccinated people than among vaccinated people under all mixing assumptions. The contact-adjusted contribution of unvaccinated people to infection risk was disproportionate, with unvaccinated people contributing to infections among those who were vaccinated at a rate higher than would have been expected based on contact numbers alone. We found that as like-with-like mixing increased, attack rates among vaccinated people decreased from 15% to 10% (and increased from 62% to 79% among unvaccinated people), but the contact-adjusted contribution to risk among vaccinated people derived from contact with unvaccinated people increased.Interpretation:Although risk associated with avoiding vaccination during a virulent pandemic accrues chiefly to people who are unvaccinated, their choices affect risk of viral infection among those who are vaccinated in a manner that is disproportionate to the portion of unvaccinated people in the population.

The remarkable speed of vaccine development, production and administration during the COVID-19 pandemic is a singular human achievement.¹ While the ability to vaccinate to herd immunity has been held back by the increasing transmissibility of novel SARS-CoV-2 variants of concern (e.g., Delta and Omicron variants),^2,3 and global distribution of vaccines is inequitable,⁴ the effectiveness of SARS-CoV-2 vaccines in reducing severity of disease and disrupting onward transmission even when breakthrough infections occur is likely to have saved many lives. The emergence of the immune-evasive Omicron variant may undermine some of these gains, although provision of booster vaccine doses may restore vaccination to a high level of potency, and vaccines developed specifically to enhance immunity to the Omicron variant may emerge in 2022.^3,5–7However, antivaccine sentiment, fuelled in part by organized disinformation efforts, has resulted in suboptimal uptake of readily available vaccines in many countries, with adverse health and economic consequences.^8–10 Although the decision not to receive vaccination is often framed in terms of the rights of individuals to opt out,^11,12 such arguments neglect the potential harms to the wider community that derive from poor vaccine uptake. Nonvaccination is expected to result in amplification of disease transmission in unvaccinated subpopulations, but the communicable nature of infectious diseases means that this also heightens risk for vaccinated populations, when vaccines confer imperfect immunity. Although assortative (like-with-like) mixing¹³ is characteristic of many communicable disease systems and may be expected to limit interaction between vaccinated and unvaccinated subpopulations to some degree, the normal functioning of society means that complete like-with-like mixing is not observed in reality. Furthermore, the airborne spread of SARS-CoV-2^14–20 means that close-range physical mixing of people from vaccinated and unvaccinated groups is not necessary for between-group disease transmission.Historically, behaviours that create health risks for the community as well as individuals have been the subject of public health regulation. This is true of communicable infectious diseases but also applies to public health statutes that limit indoor cigarette smoking²¹ and legal restrictions on driving under the influence of alcohol and other intoxicants.^22,23Simple mathematical models can often provide important insights into the behaviour of complex communicable diseases systems.^13,24,25 To better understand the implications of the interplay between vaccinated and unvaccinated populations under different assumptions about population mixing, we constructed a simple susceptible–infectious–recovered model to reproduce the dynamics of interactions between vaccinated and unvaccinated subpopulations in a predominantly vaccinated population. We sought to contrast contribution to epidemic size and risk estimates by subpopulation, and to understand the impact of mixing between vaccinated and unvaccinated groups on expected disease dynamics.     

Post-acute health care burden after SARS-CoV-2 infection: a retrospective cohort study

Background:The post-acute burden of health care use after SARS-CoV-2 infection is unknown. We sought to quantify the post-acute burden of health care use after SARS-CoV-2 infection among community-dwelling adults in Ontario by comparing those with positive and negative polymerase chain reaction (PCR) test results for SARS-CoV-2 infection.Methods:We conducted a retrospective cohort study involving community-dwelling adults in Ontario who had a PCR test between Jan. 1, 2020, and Mar. 31, 2021. Follow-up began 56 days after PCR testing. We matched people 1:1 on a comprehensive propensity score. We compared per-person-year rates for health care encounters at the mean and 99th percentiles, and compared counts using negative binomial models, stratified by sex.Results:Among 531 702 matched people, mean age was 44 (standard deviation [SD] 17) years and 51% were female. Females who tested positive for SARS-CoV-2 had a mean of 1.98 (95% CI 1.63 to 2.29) more health care encounters overall per-person-year than those who had a negative test result, with 0.31 (95% CI 0.05 to 0.56) more home care encounters to 0.81 (95% CI 0.69 to 0.93) more long-term care days. At the 99th percentile per-person-year, females who tested positive had 6.48 more days of hospital admission and 28.37 more home care encounters. Males who tested positive for SARS-CoV-2 had 0.66 (95% CI 0.34 to 0.99) more overall health care encounters per-person-year than those who tested negative, with 0.14 (95% CI 0.06 to 0.21) more outpatient encounters and 0.48 (95% CI 0.36 to 0.60) long-term care days, and 0.43 (95% CI −0.67 to −0.21) fewer home care encounters. At the 99th percentile, they had 8.69 more days in hospital per-person-year, with fewer home care (−27.31) and outpatient (−0.87) encounters.Interpretation:We found significantly higher rates of health care use after a positive SARS-CoV-2 PCR test in an analysis that matched test-positive with test-negative people. Stakeholders can use these findings to prepare for health care demand associated with post-COVID-19 condition (long COVID).

The public health effects of the COVID-19 pandemic are difficult to overstate.¹ More than 600 million SARS-CoV-2 infections and 6.5 million deaths have been reported worldwide as of September 2022,² which are likely gross undercounts as many infections go undetected.³Long-term morbidity can be caused by SARS-CoV-2 infection.^4–9 In the first pandedmic wave, as many as 27% of people admitted to hospital died or were readmitted within 60 days, and as many as 70% of people who were not admitted to hospital reported at least 1 symptom 4 months after infection.^10,11 By the World Health Organization (WHO) definition, about 10%–20% of those infected acquire a post-COVID-19 condition (long COVID).^12,13Analysis of 10 prospective surveys and the medical records of 1.1 million patients with COVID-19 diagnosis codes before the emergence of the Omicron variant showed similar findings: 7.8%–17% had symptoms 12 weeks after self-reported COVID-19, with 1.2%–4.8% reporting debilitating symptoms.¹⁴ Estimates of long COVID vary by methodology (e.g., definitions of initial infection and timing of symptoms, timing of data collection), but risk is thought to be influenced by infection severity, type of variant, patient characteristics, vaccination¹⁵ and, potentially, previous infection.¹⁶ Because each new SARS-CoV-2 infection carries some risk of long COVID, everyone remains at risk for developing the condition.Health care funders, policy-makers and clinicians need a clear understanding of the impact of long COVID on use of health care resources to allocate resources equitably now and plan for future needs.¹⁷ We sought to quantify the post-acute burden of health care use after SARS-CoV-2 infection among community-dwelling adults in Ontario.     

Suicidality among sexual minority and transgender adolescents: a nationally representative population-based study of youth in Canada

Background:Very little research has described risk of suicidal ideation and suicide attempt among transgender youth using high-quality, nationally representative data. We aimed to assess risk of suicidality among transgender and sexual minority adolescents in Canada.Methods:We analyzed a subsample of adolescents aged 15–17 years from the 2019 Canadian Health Survey on Children and Youth, a nationally representative, cross-sectional survey. We defined participants’ transgender identity (self-reported gender different from sex assigned at birth) and sexual minority status (self-reported attraction to people of the same gender) as exposures, and their self-reported previous-year suicidal ideation and lifetime suicide attempt as outcomes.Results:We included 6800 adolescents aged 15–17 years, including 1130 (16.5%) who indicated some degree of same-gender attraction, 265 (4.3%) who were unsure of their attraction and 50 (0.6%) who reported a transgender identity. Compared with cisgender, heterosexual adolescents, transgender adolescents showed 5 times the risk of suicidal ideation (95% confidence interval [CI] 3.63 to 6.75; 58% v. 10%) and 7.6 times the risk of suicide attempt (95% CI 4.76 to 12.10; 40% v. 5%). Among cisgender adolescents, girls attracted to girls had 3.6 times the risk of previous-year suicidal ideation (95% CI 2.59 to 5.08) and 3.3 times the risk of having ever attempted suicide (95% CI 1.81 to 6.06), compared with their heterosexual peers. Adolescents attracted to multiple genders had 2.5 times the risk of suicidal ideation (95% CI 2.12 to 2.98) and 2.8 times the risk of suicide attempt (95% CI 2.18 to 3.68). Youth questioning their sexual orientation had twice the risk of having attempted suicide in their lifetime (95% CI 1.23 to 3.36).Interpretation:We observed that transgender and sexual minority adolescents were at increased risk of suicidal ideation and attempt compared with their cisgender and heterosexual peers. These findings highlight the need for inclusive prevention approaches to address suicidality among Canada’s diverse youth population.

Suicide is the second leading cause of death among adolescents and young adults aged 15–24 years in Canada.^1,2 Suicidal ideation and suicide attempt are common among adolescents³ and are risk factors for death by suicide.⁴ Sexual minority youth (i.e., youth who are attracted to the same gender or multiple genders, or who identify as lesbian, gay, bisexual or queer)⁵ are known to be at increased risk of poor mental health,^6–8 including suicidal ideation and attempt.^5–10 Over the previous 2 decades, stigma around identifying as a sexual minority has reduced;⁷ however, the risk of poor mental health and of suicidality remains high among sexual minority youth.^7,11 This population is still more likely to experience bullying and peer victimization,^9,12,13 which is associated with suicidality among sexual minority adolescents.⁵Transgender youth are those whose gender identity does not match their sex assigned at birth.¹⁴ Among other terms, gender-nonconforming, nonbinary, genderqueer and genderfluid are used to describe the gender identity of a subset of young people who identify outside the gender binary (i.e., as neither male nor female) or who experience fluidity between genders.⁹ Suicidality among transgender and gender-nonconforming adolescents is not as well studied. In a Canadian survey of transgender and gender-nonconforming youth aged 14–25 years, 64% of participants reported that they had seriously considered suicide in the previous 12 months.¹⁵ Transgender and gender-nonconforming youth seem to have a higher probability of many risk factors for suicidality, including peer victimization,^8,16 family dysfunction^7,17 and barriers to accessing mental health care.¹⁸ However, the epidemiology of suicidality among transgender and gender-nonconforming youth remains understudied in population-based samples; most research on the mental health of transgender youth comes from small community samples of help-seeking youth or targeted surveys of transgender adolescents.^5,19,20 Two population-based studies from California²¹ and New Zealand²² suggested that transgender youth are at increased risk of suicidal ideation and suicide attempt. However, only the New Zealand study²² used the gold-standard measure of gender identity, contrasting adolescents’ sex assigned at birth with their self-identified gender.²³Further epidemiological research employing large, representative samples and adequate measures of gender identity is needed to understand the burden of suicidality among lesbian, gay, bisexual, transgender and queer youth. We sought to build on existing evidence to assess risk of suicidal ideation and attempt among transgender and sexual minority adolescents in Canada, as compared with their cisgender and heterosexual peers, as well as to explore the relation between suicidality and experience of bullying.     

First Nations status and emergency department triage scores in Alberta: a retrospective cohort study

Background:Previous studies have found that race is associated with emergency department triage scores, raising concerns about potential health care inequity. As part of a project on quality of care for First Nations people in Alberta, we sought to understand the relation between First Nations status and triage scores.Methods:We conducted a population-based retrospective cohort study of health administrative data from April 2012 to March 2017 to evaluate acuity of triage scores, categorized as a binary outcome of higher or lower acuity score. We developed multivariable multilevel logistic mixed-effects regression models using the levels of emergency department visit, patient (for patients with multiple visits) and facility. We further evaluated the triage of visits related to 5 disease categories and 5 specific diagnoses to better compare triage outcomes of First Nations and non–First Nations patients.Results:First Nations status was associated with lower odds of receiving higher acuity triage scores (odds ratio [OR] 0.93, 95% confidence interval [CI] 0.92–0.94) compared with non–First Nations patients in adjusted models. First Nations patients had lower odds of acute triage for all 5 disease categories and for 3 of 5 diagnoses, including long bone fractures (OR 0.82, 95% CI 0.76–0.88), acute upper respiratory infection (OR 0.90, 95% CI 0.84–0.98) and anxiety disorder (OR 0.67, 95% CI 0.60–0.74).Interpretation:First Nations status was associated with lower odds of higher acuity triage scores across a number of conditions and diagnoses. This may reflect systemic racism, stereotyping and potentially other factors that affected triage assessments.

Health outcomes are markedly worse for First Nations than non–First Nations people. Although this is largely because of inequities in the social determinants of health,^1–4 inequities in the provision of health care also exist.^5,6 Emergency departments serve as a point of accessible health care. Status First Nations patients make up 4.8% of unique patients and 9.4% of emergency visits in Alberta,⁷ and Canadian studies describe First Nations patients’ experiences with racism when seeking emergency care.^8,9Evaluating triage contributes empirically to understanding the health care of First Nations patients insofar as triage is a quantifiable, intermediate process by which systemic racism¹⁰ may influence patient outcomes. The Canadian Triage Acuity Scale¹¹ is a 5-level scale used to classify the severity of patient symptoms. Triage nurses use a brief assessment, medical history, and presenting signs and symptoms to assign each patient a triage score that determines the priority in which the patient should be seen by a provider. Therefore, accurate triage is important for patient health outcomes.¹² In practice, triage is a social interaction where local practice, biases, stereotypes and communication barriers come into play. Studies have found that women receive less acute triage scores than men,^13,14 and that racial minority^13,15–17 and Indigenous^18–20 patients receive less acute triage scores than white or non-Indigenous patients. Indeed, Indigenous patients in Canada have described a perception “of social triaging in the [emergency department], whereby decisions about who is seen first seemed to them [to be] based less on triaged clinical priorities but on the social positioning of the patient.”²¹ Differential triage scores for minority populations raise health equity concerns.As part of a larger mixed-methods project evaluating the quality of emergency care for First Nations people in Alberta, we sought to evaluate quantitative differences in emergency visit characteristics and outcomes of First Nations and non–First Nations people in Alberta. Specifically, we aimed to estimate the relation between First Nations status and acuity of triage, and to evaluate whether predictors of acuity differ by First Nations status.     

Outcomes in patients with and without disability admitted to hospital with COVID-19: a retrospective cohort study

Background:Disability-related considerations have largely been absent from the COVID-19 response, despite evidence that people with disabilities are at elevated risk for acquiring COVID-19. We evaluated clinical outcomes in patients who were admitted to hospital with COVID-19 with a disability compared with patients without a disability.Methods:We conducted a retrospective cohort study that included adults with COVID-19 who were admitted to hospital and discharged between Jan. 1, 2020, and Nov. 30, 2020, at 7 hospitals in Ontario, Canada. We compared in-hospital death, admission to the intensive care unit (ICU), hospital length of stay and unplanned 30-day readmission among patients with and without a physical disability, hearing or vision impairment, traumatic brain injury, or intellectual or developmental disability, overall and stratified by age (≤ 64 and ≥ 65 yr) using multivariable regression, controlling for sex, residence in a long-term care facility and comorbidity.Results:Among 1279 admissions to hospital for COVID-19, 22.3% had a disability. We found that patients with a disability were more likely to die than those without a disability (28.1% v. 17.6%), had longer hospital stays (median 13.9 v. 7.8 d) and more readmissions (17.6% v. 7.9%), but had lower ICU admission rates (22.5% v. 28.3%). After adjustment, there were no statistically significant differences between those with and without disabilities for in-hospital death or admission to ICU. After adjustment, patients with a disability had longer hospital stays (rate ratio 1.36, 95% confidence interval [CI] 1.19–1.56) and greater risk of readmission (relative risk 1.77, 95% CI 1.14–2.75). In age-stratified analyses, we observed longer hospital stays among patients with a disability than in those without, in both younger and older subgroups; readmission risk was driven by younger patients with a disability.Interpretation:Patients with a disability who were admitted to hospital with COVID-19 had longer stays and elevated readmission risk than those without disabilities. Disability-related needs should be addressed to support these patients in hospital and after discharge.

A successful public health response to the COVID-19 pandemic requires accurate and timely identification of, and support for, high-risk groups. There is increasing recognition that marginalized groups, including congregate care residents, racial and ethnic minorities, and people experiencing poverty, have elevated incidence of COVID-19.^1,2 Older age and comorbidities such as diabetes are also risk factors for severe COVID-19 outcomes.^3,4 One potential high-risk group that has received relatively little attention is people with disabilities.The World Health Organization estimates there are 1 billion people with disabilities globally.⁵ In North America, the prevalence of disability is 20%, with one-third of people older than 65 years having a disability.⁶ Disabilities include physical disabilities, hearing and vision impairments, traumatic brain injury and intellectual or developmental disabilities.^5,6 Although activity limitations experienced by people with disabilities are heterogeneous,^5,6 people with disabilities share high rates of risk factors for acquiring COVID-19, including poverty, residence in congregate care and being members of racialized communities.^7–9 People with disabilities may be more reliant on close contact with others to meet their daily needs, and some people with disabilities, especially intellectual developmental disabilities, may have difficulty following public health rules. Once they acquire SARS-CoV-2 infection, people with disabilities may be at risk for severe outcomes because they have elevated rates of comorbidities.¹⁰ Some disabilities (e.g., spinal cord injuries and neurologic disabilities) result in physiologic changes that increase vulnerability to respiratory diseases and may mask symptoms of acute respiratory disease, which may delay diagnosis.^11–13 There have also been reports of barriers to high-quality hospital care for patients with disabilities who have COVID-19, including communication issues caused by the use of masks and restricted access to support persons.^14–17Some studies have suggested that patients with disabilities and COVID-19 are at elevated risk for severe disease and death, with most evaluating intellectual or developmental disability.^13,18–26 Yet, consideration of disability-related needs has largely been absent from the COVID-19 response, with vaccine eligibility driven primarily by age and medical comorbidity, limited accommodations made for patients with disabilities who are in hospital, and disability data often not being captured in surveillance programs.^14–17 To inform equitable pandemic supports, there is a need for data on patients with a broad range of disabilities who have COVID-19. We sought to evaluate standard clinical outcomes in patients admitted to hospital with COVID-19²⁷ (i.e., in-hospital death, intensive care unit [ICU] admission, hospital length of stay and unplanned 30-d readmission) for patients with and without a disability, overall and stratified by age. We hypothesized that patients with a disability would have worse outcomes because of a greater prevalence of comorbidities,¹⁰ physiologic characteristics that increase morbidity risk^11–13 and barriers to high-quality hospital care.^14–17     

Rates of health services use among residents of retirement homes in Ontario: a population-based cohort study

Background:Because there are no standardized reporting systems specific to residents of retirement homes in North America, little is known about the health of this distinct population of older adults. We evaluated rates of health services use by residents of retirement homes relative to those of residents of long-term care homes and other populations of older adults.Methods:We conducted a retrospective cohort study using population health administrative data from 2018 on adults 65 years or older in Ontario. We matched the postal codes of individuals to those of licensed retirement homes to identify residents of retirement homes. Outcomes included rates of hospital-based care and physician visits.Results:We identified 54 733 residents of 757 retirement homes (mean age 86.7 years, 69.0% female) and 2 354 385 residents of other settings. Compared to residents of long-term care homes, residents of retirement homes had significantly higher rates per 1000 person months of emergency department visits (10.62 v. 4.48, adjusted relative rate [RR] 2.61, 95% confidence interval [CI] 2.55 to 2.67), hospital admissions (5.42 v. 2.08, adjusted RR 2.77, 95% CI 2.71 to 2.82), alternate level of care (ALC) days (6.01 v. 2.96, adjusted RR 1.51, 95% CI 1.48 to 1.54), and specialist physician visits (6.27 v. 3.21, adjusted RR 1.64, 95% CI 1.61 to 1.68), but a significantly lower rate of primary care visits (16.71 v. 108.47, adjusted RR 0.13, 95% CI 0.13 to 0.14).Interpretation:Residents of retirement homes are a distinct population with higher rates of hospital-based care. Our findings can help to inform policy debates about the need for more coordinated primary and supportive health care in privately operated congregate care homes.

In the continuum of care services and settings for older adults lies home care at one end and long-term care at the other.¹ Home care services may include, but are not limited to, nursing care, personal care, homemaking services, and physiotherapy and occupational therapy for older adults who live independently in their community. Home care services are publicly funded under the Ontario Health Insurance Plan (OHIP).^2,3 Long-term care homes provide access to 24-hour nursing and personal care and operate at full capacity in Ontario, with waiting lists of 6 months or longer before an older adult in the community could receive an offer for a bed.^2,4 Retirement homes are thought to fit between home care and long-term care in this continuum.¹Retirement homes are referred to as assisted-living facilities in other North American jurisdictions, and they are private, congregate living environments that deliver supportive care to adults who are 65 years of age and older.^3,5,6 These homes are often marketed to provide a lifestyle and community, and they provide a range of assisted-living care services (e.g., meals, nursing services, etc.).^5,7 Retirement homes predominately operate on a private, for-profit business model, and the room, board and services are purchased by residents.^3,5 In Ontario, retirement homes are regulated through an independent, not-for-profit regulator (i.e., Retirement Homes Regulatory Authority [RHRA]).⁵ There are more than 700 licensed retirement homes in Ontario with over 70 000 available beds occupied by over 55 000 residents, which is comparable to the number of available beds in the long-term care sector.^3,5,6,8 Retirement homes are legislated differently from long-term care homes and primarily cater to adults who do not require 24-hour nursing care.^1,5,9 Unlike long-term care homes, no standardized reporting system is available to identify and describe residents of retirement homes.¹⁰ These residents are conceptualized as having fewer needs for care because they reside in a congregate care home to support independent living; however, this has been difficult to verify given there are no population-level data.A body of literature from the United States has described residents of assisted-living facilities and the sector,^11–17 but Canadian literature is comparatively nascent. Canadian studies have investigated transitions to a long-term care home, risk of hospital admission among those who live with dementia, and life events and health conditions associated with the transition to a congregate care setting.^7,9,18–20 At present, a Canadian population-level cohort of residents of retirement homes that describes the individual-level characteristics and use of health services of the older adults who reside in these homes appears to be lacking. Therefore, it is difficult to position this sector in the gradient of services and housing options for older adults in Canada.We created a population-level cohort of residents in retirement homes and sought to evaluate their rates of health services utilization relative to residents of long-term care homes and other populations of older adults (i.e., home care recipients and community-dwelling older adults) in Ontario.     

Likelihood of coronary angiography among First Nations patients with acute myocardial infarction

Background:

Morbidity due to cardiovascular disease is high among First Nations people. The extent to which this may be related to the likelihood of coronary angiography is unclear. We examined the likelihood of coronary angiography after acute myocardial infarction (MI) among First Nations and non–First Nations patients.

Methods:

Our study included adults with incident acute MI between 1997 and 2008 in Alberta. We determined the likelihood of angiography among First Nations and non–First Nations patients, adjusted for important confounders, using the Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease (APPROACH) database.

Results:

Of the 46 764 people with acute MI, 1043 (2.2%) were First Nations. First Nations patients were less likely to receive angiography within 1 day after acute MI (adjusted odds ratio [OR] 0.73, 95% confidence interval [CI] 0.62–0.87). Among First Nations and non–First Nations patients who underwent angiography (64.9%), there was no difference in the likelihood of percutaneous coronary intervention (PCI) (adjusted hazard ratio [HR] 0.92, 95% CI 0.83–1.02) or coronary artery bypass grafting (CABG) (adjusted HR 1.03, 95% CI 0.85–1.25). First Nations people had worse survival if they received medical management alone (adjusted HR 1.38, 95% CI 1.07–1.77) or if they underwent PCI (adjusted HR 1.38, 95% CI 1.06–1.80), whereas survival was similar among First Nations and non–First Nations patients who received CABG.

Interpretation:

First Nations people were less likely to undergo angiography after acute MI and experienced worse long-term survival compared with non–First Nations people. Efforts to improve access to angiography for First Nations people may improve outcomes.Although cardiovascular disease has been decreasing in Canada,¹ First Nations people have a disproportionate burden of the disease. First Nations people in Canada have a 2.5-fold higher prevalence of cardiovascular disease than non–First Nations people,² with hospital admissions for cardiovascular-related events also increasing.³The prevalence of cardiovascular disease in First Nations populations is presumed to be reflective of the prevalence of cardiovascular risk factors.^4–7 However, the disproportionate increase in rates of hospital admission suggests that suboptimal management of cardiovascular disease or its risk factors may also influence patient outcomes.^2,3 Racial disparities in the quality of cardiovascular care resulting in adverse outcomes have been documented, although most studies have focused on African-American, Hispanic and Asian populations.^8,9 As a result, it is unclear whether suboptimal delivery of guideline-recommended treatment contributes to increased cardiovascular morbidity and mortality among First Nations people.^10–12We undertook a population-based study involving adults with incident acute myocardial infarction (MI) to examine the receipt of guideline-recommended coronary angiography among First Nations and non–First Nations patients.^10–12 Among patients who underwent angiography, we sought to determine whether there were differences between First Nations and non–First Nations patients in the likelihood of revascularization and long-term survival.     

Regional collaborative home-based palliative care and health care outcomes among adults with heart failure

BackgroundInnovative models of collaborative palliative care are urgently needed to meet gaps in end-of-life care among people with heart failure. We sought to determine whether regionally organized, collaborative, home-based palliative care that involves cardiologists, primary care providers and palliative care specialists, and that uses shared decision-making to promote goal- and need-concordant care for patients with heart failure, was associated with a greater likelihood of patients dying at home than in hospital.MethodsWe conducted a population-based matched cohort study of adults who died with chronic heart failure across 2 large health regions in Ontario, Canada, between 2013 and 2019. The primary outcome was location of death. Secondary outcomes included rates of health care use, including unplanned visits to the emergency department, hospital admissions, hospital lengths of stay, admissions to the intensive care unit, number of visits with primary care physicians or cardiologists, number of home visits by palliative care physicians or nurse practitioners, and number of days spent at home.ResultsPatients who received regionally organized, collaborative, home-based palliative care (n = 245) had a 48% lower associated risk of dying in hospital (relative risk 52%, 95% confidence interval 44%–66%) compared with the matched cohort (n = 1172) who received usual care, with 101 (41.2%) and 917 (78.2%) patients, respectively, dying in hospital (number needed to treat = 3). Additional associated benefits of the collaborative approach included higher rates of clinician home visits, longer time to first hospital admission, shorter hospital stays and more days spent at home.InterpretationAdoption of a model of regionally organized, collaborative, home-based palliative care that uses shared decision-making may improve end-of-life outcomes for people with chronic heart failure.

Innovative models of collaborative, interdisciplinary palliative care that use shared decision-making to promote goal- and need-concordant care are urgently needed to meet rising demand among people with heart failure.^1,2 Between 2010 and 2015, 75% of people with heart failure in Ontario died in hospital, despite 70% of people preferring an out-of-hospital death and 90% preferring end-of-life health care delivery at home.^3–5 Most people also prioritize improvements in quality of life at the end of life over extension of life.⁶ Admission to hospital near the end of life is often perceived as undesirable and may result in the provision of unwanted care, whereas home visits near the end of life tend to focus on comfort and are associated with higher rates of death at home.^4,5,7,8 These preferences are recognized at a system level, such that avoidance of unwanted health care and at-home death are considered quality indicators for end-of-life care.^9–11 However, delivering high-quality care for people with heart failure who are near the end of their life is challenging because of their unpredictable illness course and limited capacity of specialist palliative care.^4,12–14Many studies, including a recent meta-analysis, have shown that home-based palliative care is associated with improved quality of life and symptoms, reduced health care use and a higher likelihood of a home death among people with heart failure. ^{4,8,12,13,15,16} However, only 32% of people with heart failure received home-based palliative care near the end of life in Ontario.^4,8 Several randomized controlled trials explored the effects of collaborative care models for people with heart failure; ^12–16 the results were mixed regarding quality of life, symptoms and health care use.^13,17–21 Some trials reported that palliative care resulted in improvements in quality of life and reductions in burdensome symptoms and hospital admissions, whereas others reported no change in these outcomes.¹³ Most studies were single centre and none evaluated a model of regional organization and in-person home visits as a scalable approach.Given the need to address end-of-life care gaps for people with heart failure, we sought to determine whether regionally organized, collaborative, home-based palliative care (CHPC) — involving cardiology, primary care and palliative care — was associated with increased rates of out-of-hospital death among adults who died with heart failure.     

Diversity among health care leaders in Canada: a cross-sectional study of perceived gender and race

Background:Diverse health care leadership teams may improve health care experiences and outcomes for patients. We sought to explore the race and gender of hospital and health ministry executives in Canada and compare their diversity with that of the populations they serve.Methods:This cross-sectional study included leaders of Canada’s largest hospitals and all provincial and territorial health ministries. We included individuals listed on institutional websites as part of the leadership team if a name and photo were available. Six reviewers coded and analyzed the perceived race and gender of leaders, in duplicate. We compared the proportion of racialized health care leaders with the race demographics of the general population from the 2016 Canadian Census.Results:We included 3056 leaders from 135 institutions, with reviewer concordance on gender for 3022 leaders and on race for 2946 leaders. Reviewers perceived 37 (47.4%) of 78 health ministry leaders as women, and fewer than 5 (< 7%) of 80 as racialized. In Alberta, Saskatchewan, Prince Edward Island and Nova Scotia, provinces with a centralized hospital executive team, reviewers coded 36 (50.0%) of 72 leaders as women and 5 (7.1%) of 70 as racialized. In British Columbia, New Brunswick and Newfoundland and Labrador, provinces with hospital leadership by region, reviewers perceived 120 (56.1%) of 214 leaders as women and 24 (11.5%) of 209 as racialized. In Manitoba, Ontario and Quebec, where leadership teams exist at each hospital, reviewers perceived 1326 (49.9%) of 2658 leaders as women and 243 (9.2%) of 2633 as racialized. We calculated the representation gap between racialized executives and the racialized population as 14.5% for British Columbia, 27.5% for Manitoba, 20.7% for Ontario, 12.4% for Quebec, 7.6% for New Brunswick, 7.3% for Prince Edward Island and 11.6% for Newfoundland and Labrador.Interpretation:In a study of more than 3000 health care leaders in Canada, gender parity was present, but racialized executives were substantially under-represented. This work should prompt health care institutions to increase racial diversity in leadership.

Race and gender-based disparities in health care leadership^1–4 may negatively affect the health of marginalized patients.^5,6 Diverse leadership is an integral step in establishing equitable health care institutions that serve the needs of all community members.⁷ Many barriers prevent racialized people, women and gender nonbinary individuals from attaining leadership positions, including reduced access to networking opportunities, ^8–10 discrimination from patients and colleagues^2,11–13 and an institutional culture that views white, male leaders as most effective. ^14,15 The intersectional effects of discrimination may intensify these barriers for racialized women and nonbinary people.^16,17 Fundamentally, diversity and inclusion in our institutions is important on the basis of basic human rights for all people.¹⁸Health care leadership in Europe and the United States is thought to lack gender and racial diversity.^19–22 The degree to which these imbalances exist across Canadian health care institutions is not clear. Despite past evidence that men hold a disproportionate number of health care leadership positions in Canada,^23,24 a recent study noted gender parity among leaders of provincial and territorial ministries of health.²⁵ Among university faculty^26,27 and administration, ²⁸ racialized individuals appear to be under-represented, suggesting that a similar trend may exist in health care leadership.Race and gender can be studied in many ways.²⁹ Perceived race is a measure of “the race that others believe you to be,” and these assessments “influence how people are treated and form the basis of racial discrimination including nondeliberate actions that nonetheless lead to socioeconomic inequities.”²⁹ Similarly, perceived gender refers to an observer’s assumptions about a person’s gender, which can lead to differential and unfair treatment. ³⁰ Assessing perceived race and gender provides crucial insights into the ways in which social inequalities are informed and produced.²⁹ In this study, we sought to identify the perceived race and gender of hospital executive leaders in Canada and of nonelected leaders of the provincial and territorial health ministries. Furthermore, we wanted to analyze how the perceived racial composition of health care leadership compares with the racial composition of the population in the geographic areas that these leaders serve.     

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.     

Epidemiology of diabetes mellitus among First Nations and non-First Nations adults

Background

First Nations people in Canada experience a disproportionate burden of type 2 diabetes mellitus. To increase our understanding of this evolving epidemic, we compared the epidemiology of diabetes between First Nations and non-First Nations adults in Saskatchewan from 1980 to 2005.

Methods

We used administrative databases to perform a population-based study of diabetes frequency, incidence and prevalence in adults by ethnic background, year, age and sex.

Results

We identified 8275 First Nations and 82 306 non-First Nations people with diabetes from 1980 to 2005. Overall, the incidence and prevalence of diabetes were more than 4 times higher among First Nations women than among non-First Nations women and more than 2.5 times higher among First Nations men than among non-First Nations men. The number of incident cases of diabetes was highest among First Nations people aged 40–49 , while the number among non-First Nations people was greatest in those aged 70 or more years. The prevalence of diabetes increased over the study period from 9.5% to 20.3% among First Nations women and from 4.9% to 16.0% among First Nations men. Among non-First Nations people, the prevalence increased from 2.0% to 5.5% among women and from 2.0% to 6.2% among men. By 2005, almost 50% of First Nations women and more than 40% of First Nations men aged 60 or older had diabetes, compared with less than 25% of non-First Nations men and less than 20% of non-First Nations women aged 80 or older.

Interpretation

First Nations adults are experiencing a diabetes epidemic that disproportionately affects women during their reproductive years. This ethnicity-based pattern suggests diverse underlying mechanisms that may include differences in the diabetogenic impact of gestational diabetes.The global epidemic of type 2 diabetes mellitus disproportionately affects indigenous and developing populations.¹ Although genotypic variants related to energy balance may underlie this epidemic,² the rapid emergence of type 2 diabetes in genetically diverse populations worldwide is most likely caused by environmental factors. Increasing rates of type 2 diabetes among Canada’s First Nations people, for example, parallel an epidemic of overweight and obesity that has coincided with socio-cultural disruption and a loss of traditional lifestyles.³In Saskatchewan in 1937, diabetes was not detected among the 1500 First Nations people who underwent a tuberculosis survey.⁴ By 1990, almost 10% of the province’s First Nations adults had diabetes;⁵ by 2006, the proportion was over 20%,⁶ while it remained at about 6% in the general population.^5,6 Although an increased prevalence of diabetes among First Nations people has also been documented in other Canadian provinces,³ only recently have consistent diabetes case definitions applied to health care system administrative databases been used to compare differences between large populations of First Nations and non-First Nations people.^7–9We sought to describe the epidemiology of diabetes in Saskatchewan from 1980 to 2005. We reasoned that finding ethnicity-based differences in trends and patterns of type 2 diabetes over the longest period reported for a Canadian jurisdiction would help to clarify the underlying mechanisms behind known disparities and translate into more effective diabetes prevention and management initiatives.     

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     

Differential mortality and the excess burden of end-stage renal disease among First Nations people with diabetes mellitus: a competing-risks analysis

Background:

Diabetes-related end-stage renal disease disproportionately affects indigenous peoples. We explored the role of differential mortality in this disparity.

Methods:

In this retrospective cohort study, we examined the competing risks of end-stage renal disease and death without end-stage renal disease among Saskatchewan adults with diabetes mellitus, both First Nations and non–First Nations, from 1980 to 2005. Using administrative databases of the Saskatchewan Ministry of Health, we developed Fine and Gray subdistribution hazards models and cumulative incidence functions.

Results:

Of the 90 429 incident cases of diabetes, 8254 (8.9%) occurred among First Nations adults and 82 175 (90.9%) among non–First Nations adults. Mean age at the time that diabetes was diagnosed was 47.2 and 61.6 years, respectively (p < 0.001). After adjustment for sex and age at the time of diabetes diagnosis, the risk of end-stage renal disease was 2.66 times higher for First Nations than non–First Nations adults (95% confidence interval [CI] 2.24–3.16). Multivariable analysis with adjustment for sex showed a higher risk of death among First Nations adults, which declined with increasing age at the time of diabetes diagnosis. Cumulative incidence function curves stratified by age at the time of diabetes diagnosis showed greatest risk for end-stage renal disease among those with onset of diabetes at younger ages and greatest risk of death among those with onset of diabetes at older ages.

Interpretation:

Because they are typically younger when diabetes is diagnosed, First Nations adults with this condition are more likely than their non–First Nations counterparts to survive long enough for end-stage renal disease to develop. Differential mortality contributes substantially to ethnicity-based disparities in diabetes-related end-stage renal disease and possibly to chronic diabetes complications. Understanding the mechanisms underlying these disparities is vital in developing more effective prevention and management initiatives.Indigenous peoples experience an excess burden of diabetes-related end-stage renal disease,^1–4 but the reasons for this disparity are incompletely understood. Although the increase in end-stage renal disease among indigenous peoples has paralleled the global emergence of type 2 diabetes mellitus,⁵ disparities in end-stage renal disease among Canada’s First Nations adults persist² after adjustment for elevated prevalence of diabetes.⁶ In an earlier study, we suggested that First Nations adults might be more prone to diabetic nephropathy and might experience more rapid progression to end-stage renal disease.⁷ However, although albuminuria is more prevalent in this population,⁸ affected individuals unexpectedly have a longer average time from diagnosis of diabetes to end-stage renal disease than people from non–First Nations populations.² These findings could be explained by a younger age at the time of diabetes diagnosis⁶ and lower mortality among those with chronic kidney disease.⁸ An age-related survival benefit among First Nations adults with diabetes could lead to longer exposure to the metabolic consequences of diabetes and greater likelihood of end-stage renal disease.Our objective was to examine the contribution of differential mortality to disparities in diabetes-related end-stage renal disease within large populations of indigenous and non-indigenous North Americans. Accordingly, we used competing-risks survival analysis to compare the simultaneous risks of diabetes-related end-stage renal disease and death without end-stage renal disease among First Nations and non–First Nations adults.⁹     

Association between First Nations ethnicity and progression to kidney failure by presence and severity of albuminuria

Background:

Despite a low prevalence of chronic kidney disease (estimated glomerular filtration rate [GFR] < 60 mL/min per 1.73 m²), First Nations people have high rates of kidney failure requiring chronic dialysis or kidney transplantation. We sought to examine whether the presence and severity of albuminuria contributes to the progression of chronic kidney disease to kidney failure among First Nations people.

Methods:

We identified all adult residents of Alberta (age ≥ 18 yr) for whom an outpatient serum creatinine measurement was available from May 1, 2002, to Mar. 31, 2008. We determined albuminuria using urine dipsticks and categorized results as normal (i.e., no albuminuria), mild, heavy or unmeasured. Our primary outcome was progression to kidney failure (defined as the need for chronic dialysis or kidney transplantation, or a sustained doubling of serum creatinine levels). We calculated rates of progression to kidney failure by First Nations status, by estimated GFR and by albuminuria category. We determined the relative hazard of progression to kidney failure for First Nations compared with non–First Nations participants by level of albuminuria and estimated GFR.

Results:

Of the 1 816 824 participants we identified, 48 669 (2.7%) were First Nations. First Nations people were less likely to have normal albuminuria compared with non–First Nations people (38.7% v. 56.4%). Rates of progression to kidney failure were consistently 2- to 3-fold higher among First Nations people than among non–First Nations people, across all levels of albuminuria and estimated GFRs. Compared with non–First Nations people, First Nations people with an estimated GFR of 15.0–29.9 mL/min per 1.73 m² had the highest risk of progression to kidney failure, with similar hazard ratios for those with normal and heavy albuminuria.

Interpretation:

Albuminuria confers a similar risk of progression to kidney failure for First Nations and non–First Nations people.Severe chronic kidney disease (estimated glomerular filtration rate [GFR] < 30 mL/min per 1.73 m²) is almost 2-fold higher, and rates of end-stage kidney disease (defined as the need for chronic dialysis or kidney transplantation) are 4-fold higher, among First Nations people compared with non–First Nations people in Canada.^1,2 The reasons for the higher rate of end-stage kidney disease when there is a lower prevalence of earlier stages of chronic kidney disease in First Nations people (estimated GFR 30–60 mL/min per 1.73 m²) are unclear. The rising incidence of diabetes is seen as the major cause of kidney failure among First Nations people;³ however, First Nations people without diabetes are also 2–3 times more likely to eventually have kidney failure.⁴ These observations suggest that diabetes is not the sole determinant of risk for kidney failure and that there are yet undefined factors that may accelerate the progression of chronic kidney disease in the First Nations population.⁵Recent studies have highlighted the prognostic importance of albuminuria as a risk factor for kidney failure.⁶ Although ethnic variations in the prevalence and severity of albuminuria and their association with renal outcomes have been reported, these studies are primarily limited to non–First Nations populations.⁷ A limited number of studies have reported an increased prevalence of albuminuria among First Nations people, suggesting the potential association between albuminuria and risk of kidney failure.^8,9 We sought to measure the presence and severity of albuminuria and estimate the risk of progression to kidney failure for First Nations people compared with non–First Nations people using a community-based cohort.     

Emergency health care use and follow-up among sociodemographic groups of children who visit emergency departments for mental health crises

Background:

Previous studies of differences in mental health care associated with children’s sociodemographic status have focused on access to community care. We examined differences associated with visits to the emergency department.

Methods:

We conducted a 6-year population-based cohort analysis using administrative databases of visits (n = 30 656) by children aged less than 18 years (n = 20 956) in Alberta. We measured differences in the number of visits by socioeconomic and First Nations status using directly standardized rates. We examined time to return to the emergency department using a Cox regression model, and we evaluated time to follow-up with a physician by physician type using a competing risks model.

Results:

First Nations children aged 15–17 years had the highest rate of visits for girls (7047 per 100 000 children) and boys (5787 per 100 000 children); children in the same age group from families not receiving government subsidy had the lowest rates (girls: 2155 per 100 000 children; boys: 1323 per 100 000 children). First Nations children (hazard ratio [HR] 1.64; 95% confidence interval [CI] 1.30–2.05), and children from families receiving government subsidies (HR 1.60, 95% CI 1.30–1.98) had a higher risk of return to an emergency department for mental health care than other children. The longest median time to follow-up with a physician was among First Nations children (79 d; 95% CI 60–91 d); this status predicted longer time to a psychiatrist (HR 0.47, 95% CI 0.32–0.70). Age, sex, diagnosis and clinical acuity also explained post-crisis use of health care.

Interpretation:

More visits to the emergency department for mental health crises were made by First Nations children and children from families receiving a subsidy. Sociodemographics predicted risk of return to the emergency department and follow-up care with a physician.Emergency departments are a critical access point for mental health care for children who have been unable to receive care elsewhere or are in crisis.¹ Care provided in an emergency department can stabilize acute problems and facilitate urgent follow-up for symptom management and family support.^1,2Race, ethnic background and socioeconomic status have been linked to a crisis-oriented care patterns among American children.^3,4 Minority children are less likely than white children to have received mental health treatment before an emergency department visit,^3,4 and uninsured children are less likely to receive an urgent mental health evaluation when needed.⁴ Other studies, however, have shown no relation between sociodemographic status and mental health care,^5,6 and it may be that different health system characteristics (e.g., pay-for-service, insurance coverage, publicly funded care) interact with sociodemographic status to influence how mental health resources are used. Canadian studies are largely absent in this discussion, despite a known relation between lower income and poorer mental health status,⁷ nationwide documentation of disparities faced by Aboriginal children,^8–10 and government-commissioned reviews that highlight deficits in universal access to mental health care.¹¹We undertook the current study to examine whether sociodemographic differences exist in the rates of visits to emergency departments for mental health care and in the use of post-crisis health care services for children in Alberta. Knowledge of whether differences exist for children with mental health needs may help identify children who could benefit from earlier intervention to prevent illness destabilization and children who may be disadvantaged in the period after the emergency department visit. We hypothesized that higher rates of emergency department use, lower rates of follow-up physician visits after the initial emergency department visit, and a longer time to physician follow-up would be observed among First Nations children and children from families receiving government social assistance.