Medication Adherence in the General Population

Background

Adherence to medication is low in specific populations who need chronic medication. However, adherence to medication is also of interest in a more general fashion, independent of specific populations or side effects of particular drugs. If clinicians and researchers expect patients to show close to full adherence, it is relevant to know how likely the achievement of this goal is. Population based rates can provide an estimate of efforts needed to achieve near complete adherence in patient populations. The objective of the study was to collect normative data for medication nonadherence in the general population.

Methods and Findings

We assessed 2,512 persons (a representative sample of German population). Adherence was measured by Rief Adherence Index. We also assessed current medication intake and side effects. We found that at least 33% of Germans repeatedly fail to follow their doctor''s recommendations regarding pharmacological treatments and only 25% of Germans describe themselves as fully adherent. Nonadherence to medication occurs more often in younger patients with higher socioeconomic status taking short-term medications than in older patients with chronic conditions. Experience with medication side effects was the most prominent predictor of nonadherence.

Conclusions

The major strengths of our study are a representative sample and a novel approach to assess adherence. Nonadherece seems to be commonplace in the general population. Therefore adherence cannot be expected per se but needs special efforts on behalf of prescribers and public health initiatives. Nonadherence to medication should not only be considered as a drug-specific behaviour problem, but as a behaviour pattern that is independent of the prescribed medication.     

What Potentially Modifiable Factors are Associated With Treatment Nonadherence in Pediatric Growth Hormone Deficiency? A Quantitative Study

ObjectiveA recent systematic review reported that up to 71% of patients with growth hormone deficiency and their families are nonadherent to treatment as prescribed. Nonadherence to growth hormone treatment presents a substantial and costly problem for the patient, health care provider, and health care system. The current study uniquely investigated the potentially modifiable factors associated with treatment nonadherence in this endocrine disorder.MethodsThe cross-sectional study was conducted among 82 parent/caregivers of children with growth hormone deficiency who were receiving growth hormone treatment. Self-report questionnaires investigated parent/caregiver perceptions and experiences of their child’s condition and prescribed treatment, in addition to their perceived relationship with their health care professional. The 8-item Morisky medication adherence scale was used for the assessment of treatment adherence.ResultsSixty-two percent of parents/caregivers were found to be nonadherent to growth hormone treatment as prescribed. Illness perceptions (consequences, identity, and coherence) and treatment concerns were found to be significantly associated with treatment adherence, as was the quality of the health care professional–parent/caregiver relationship.ConclusionThe study confirmed the extent of the adherence problem evident among the pediatric growth hormone deficiency population. In addition, it presented an insight into the explanatory factors that underpin nonadherence to growth hormone treatment. Our findings can be used to inform the development of adherence-focused interventions, with the purpose of supporting patients and their families and improving the use of prescribed growth hormone treatment within endocrine clinical practice.     

Effectiveness of treatments for hypertension in a sample of Colombian patients

Hypertension represents a high health cost because of its prevalence, its low level of diagnosis and control, and its role as a primary risk factor for other cardiovascular diseases. According to the JNC 7 report, hypertensive individuals have blood pressures of 140/90 mm Hg or higher; recommended treatment reduces these values to below 120/80 mm Hg. Co-morbidity and the presence of other risk factors must also be considered. In a random sample of 458 hypertensive patients from 6 Colombian cities, the effectiveness, tolerance and adherence to treatment was compared in cases with treatment of at least one year's duration. During routine blood pressure examinations, trained nurses obtained patient consent and additional anthropometric data, such as including co-morbidity, risk factors, antihypertensive medication prescribed, dosages and usage of unrelated medications. Some of the data were retrieved from the patients' medical histories. The average age of the patients was 57.6 +/- 13 years, with 67.5% women; 92% with complete adherence to the treatment and 59% not reporting adverse events associated with the medication. Forty-four percent were treated with antihypertensive monotherapy with the most commonly prescribed medications as follows (in order): hydrochlorothiazide, verapamil, enalapril, metoprolol and propanolol. Forty-five percent (n=207) were control patients, 35% were in a hypertensive stage 1 and 19.7% were in stage 2. Multivariate analysis showed that uncontrolled hypertension was significantly associated with geriatrics receiving a combination of antihypertensive medication and residence in three cities--Ibagué, Barranquilla and Manizales--where smaller daily doses of hypertensive medications are prescribed. Health care teams are advised to adjust doses carefully to obtain clearly defined therapeutic objectives.     

Rates of Intentional and Unintentional Nonadherence to Peritoneal Dialysis Regimes and Associated Factors

With increasing emphasis on expanding home-based dialysis, there is a need to understand adherence outcomes. This study set out to examine the prevalence and predictors of nonadherence among patients undergoing peritoneal dialysis. A cross sectional sample of 201 peritoneal dialysis patients recruited between 2010–2011 from Singapore General Hospital completed measures of quality of life, medication beliefs, self-efficacy and emotional distress. Nonadherence rates were high; 18% for dialysis, 46% for medication and 78% for diet. Intentional nonadherence was more common for dialysis (p = .03), whereas unintentional nonadherence was more common for medication (p = .002). Multivariate models indicated significant associations for higher education (intermediate vs low OR = 3.18, high vs low OR = 4.70), lower environment quality of life (OR = 0.79), dialysis self-efficacy (OR = 0.80) with dialysis nonadherence; higher education (OR = 2.22), self-care peritoneal dialysis (OR = 3.10), perceived necessity vs concerns over medication (OR = 0.90), self-efficacy (OR = 0.76) with nonadherence to medication. The odds for nonadherence to diet were higher among patients who were younger (OR = 0.96), of Chinese ethnicity (OR = 2.99) and those reporting better physical health (OR = 1.30) and lower self-efficacy (OR = 0.49). Nonadherence is common in peritoneal dialysis. Self-efficacy and beliefs about medication are promising targets for interventions designed to improve adherence.     

Nonadherence to antipsychotic treatment in patients with schizophrenic disorders

Adherence to treatment is a general indicator of quality and success of communication between the physician and the patient. It means the extent to which patient behaviour, in terms of taking medications, following diets, or executing life-style changes, coincides with medical or health advice. Nonadherence to antipsychotic therapy in patients with schizophrenia is far more widespread than clinicians assume. Lower nonadherence in therapy based on antipsychotics of the second generation compared with conventional medications has already been indicated by early reports. The consequences of nonadherence include exacerbation of symptoms, an increased relapse rate, psychiatric hospitalization hospitalisation, and less favourable patient prognosis. There are several factors that cause treatment nonadherence in schizophrenia: causes derived from the schizophrenic disorder itself, patient characteristics, causes associated associated with the health-care system, and the antipsychotic treatment itself.     

Medication adherence in type 2 diabetes: the ENTRED study 2007, a French Population-Based Study

Background

Adherence to prescribed medications is a key dimension of healthcare quality. The aim of this large population-based study was to evaluate self-reported medication adherence and to identify factors linked with poor adherence in patients with type 2 diabetes in France.

Methodology

The ENTRED study 2007, a French national survey of people treated for diabetes, was based on a representative sample of patients who claimed reimbursement for oral hypoglycaemic agents and/or insulin at least three times between August 2006 and July 2007, and who were randomly selected from the database of the two main National Health Insurance Systems. Medication adherence was determined using a six-item self-administered questionnaire. A multinomial polychotomous logistic regression model was used to identify factors associated with medication adherence in the 3,637 persons with type 2 diabetes.

Principal Findings

Thirty nine percent of patients reported good medication adherence, 49% medium adherence and 12% poor adherence. The factors significantly associated with poor adherence in multivariate analysis were socio-demographic factors: age <45 years, non-European geographical origin, financial difficulties and being professionally active; disease and therapy-related factors: HbA_1c>8% and existing diabetes complications; and health care-related factors: difficulties for taking medication alone, decision making by the patient only, poor acceptability of medical recommendations, lack of family or social support, need for information on treatment, reporting no confidence in the future, need for medical support and follow-up by a specialist physician.

Conclusions

In a country with a high level of access to healthcare, our study demonstrated a substantial low level of medication adherence in type 2 diabetic patients. Better identification of those with poor adherence and individualised suitable recommendations remain essential for better healthcare management.     

Perspective on hypertension in the elderly.

More than half of elderly men and women have hypertension, leading to a significant risk of increased morbidity and mortality. The cause of hypertension in this age group is unknown. Left ventricular hypertrophy is frequently present, often associated with diastolic dysfunction. Systolic hypertension in the elderly increases the risk of cardiovascular disease, but there are no good data to show that the treatment of isolated systolic hypertension reduces the morbidity or mortality. Good evidence indicates that antihypertensive treatment in this group decreases cardiovascular morbidity and mortality up to age 80, so most elderly hypertensive patients should be treated. An empiric trial of nonpharmacologic therapy can be initiated in those with mild hypertension and no cardiovascular disease, but most patients will require drug therapy. Most elderly hypertensive patients have accompanying illnesses for which they may or may not be taking medications. Some antihypertensive drugs exacerbate coexisting diseases while others augment treatment regimens. Similarly, drugs may interact in a beneficial or adverse way. Finally, drug metabolism is altered by age, leading to problems with toxicity or diminished efficacy. The choice of medication should be based on all such considerations, including the cost and convenience of the drugs available.     

The Cost-Effectiveness of Low-Cost Essential Antihypertensive Medicines for Hypertension Control in China: A Modelling Study

Background

Hypertension is China’s leading cardiovascular disease risk factor. Improved hypertension control in China would result in result in enormous health gains in the world’s largest population. A computer simulation model projected the cost-effectiveness of hypertension treatment in Chinese adults, assuming a range of essential medicines list drug costs.

Methods and Findings

The Cardiovascular Disease Policy Model-China, a Markov-style computer simulation model, simulated hypertension screening, essential medicines program implementation, hypertension control program administration, drug treatment and monitoring costs, disease-related costs, and quality-adjusted life years (QALYs) gained by preventing cardiovascular disease or lost because of drug side effects in untreated hypertensive adults aged 35–84 y over 2015–2025. Cost-effectiveness was assessed in cardiovascular disease patients (secondary prevention) and for two blood pressure ranges in primary prevention (stage one, 140–159/90–99 mm Hg; stage two, ≥160/≥100 mm Hg). Treatment of isolated systolic hypertension and combined systolic and diastolic hypertension were modeled as a reduction in systolic blood pressure; treatment of isolated diastolic hypertension was modeled as a reduction in diastolic blood pressure. One-way and probabilistic sensitivity analyses explored ranges of antihypertensive drug effectiveness and costs, monitoring frequency, medication adherence, side effect severity, background hypertension prevalence, antihypertensive medication treatment, case fatality, incidence and prevalence, and cardiovascular disease treatment costs. Median antihypertensive costs from Shanghai and Yunnan province were entered into the model in order to estimate the effects of very low and high drug prices. Incremental cost-effectiveness ratios less than the per capita gross domestic product of China (11,900 international dollars [Int$] in 2015) were considered cost-effective. Treating hypertensive adults with prior cardiovascular disease for secondary prevention was projected to be cost saving in the main simulation and 100% of probabilistic simulation results. Treating all hypertension for primary and secondary prevention would prevent about 800,000 cardiovascular disease events annually (95% uncertainty interval, 0.6 to 1.0 million) and was borderline cost-effective incremental to treating only cardiovascular disease and stage two patients (2015 Int$13,000 per QALY gained [95% uncertainty interval, Int$10,000 to Int$18,000]). Of all one-way sensitivity analyses, assuming adherence to taking medications as low as 25%, high Shanghai drug costs, or low medication efficacy led to the most unfavorable results (treating all hypertension, about Int$47,000, Int$37,000, and Int$27,000 per QALY were gained, respectively). The strengths of this study were the use of a recent Chinese national health survey, vital statistics, health care costs, and cohort study outcomes data as model inputs and reliance on clinical-trial-based estimates of coronary heart disease and stroke risk reduction due to antihypertensive medication treatment. The limitations of the study were the use of several sources of data, limited clinical trial evidence for medication effectiveness and harms in the youngest and oldest age groups, lack of information about geographic and ethnic subgroups, lack of specific information about indirect costs borne by patients, and uncertainty about the future epidemiology of cardiovascular diseases in China.

Conclusions

Expanded hypertension treatment has the potential to prevent about 800,000 cardiovascular disease events annually and be borderline cost-effective in China, provided low-cost essential antihypertensive medicines programs can be implemented.     

Effects of gender and depression on oral medication adherence in persons with type 2 diabetes mellitus

Background: In a range of chronic conditions including diabetes, it has been observed that depressive symptoms may be associated with nonadherence to medications.Objective: The objective of the study was to determine the main effects, and interactive effect, of depression and gender on patients adherence to oral diabetes medications.Methods: A cross-sectional design was employed, in which persons with type 2 diabetes mellitus completed a questionnaire regarding medication use behaviors, depressive symptoms (measured by the 8-item Patient Health Questionnaire [PHQ-8]), health beliefs, and demographics. A 2 x 2 factorial analysis of variance was used to determine the effects of gender and depression on medication adherence after adjusting for age, education, self efficacy, social support, and number of doses of diabetes medications.Results: Of the 391 respondents who completed the questionnaire, 73 (18.7%) were categorized as having depression (ie, PHQ-8 score >10). Overall, women (n = 196) had a mean (SD) score of 6.10 (6.19) on the PHQ-8, and men (n = 195) had a lower score of 4.62 (5.28) (t = 2.75; P < 0.01). There was a significant main effect of depression, but not gender, on patients' adherence to diabetes medications in that those who were categorized as depressed had significantly worse adherence to diabetes medications (F = 4.82; P = 0.03).Additionally, there was a significant “gender x depression” interaction effect on adherence (F = 5.93; P = 0.01). Men with depression had mean adherence scores that indicated more nonadherence than did men without depression (9.44 [3.45] vs 7.47 [2.50], respectively), but adherence varied little between women with depression and women without depression (7.83 [2.69] vs 7.55 [2.58], respectively).Conclusions: The association between depression and medication adherence appears to be stronger in men than in women. Clinicians should be cognizant of the potential effect of depression on self-care for diabetes, particularly in men with depressive symptoms.     

Adherence to prescribed antihypertensive drug treatments: longitudinal study of electronically compiled dosing histories

Objective To describe characteristics of dosing history in patients prescribed a once a day antihypertensive medication.Design Longitudinal database study.Setting Clinical studies archived in database for 1989-2006.Participants Patients who participated in the studies whose dosing histories were available through electronic monitoring.Main outcome measures Persistence with prescribed antihypertensive treatment and execution of their once a day drug dosing regimens.Results The database contained dosing histories of 4783 patients with hypertension. The data came from 21 phase IV clinical studies, with lengths ranging from 30 to 330 days and involving 43 different antihypertensive drugs, including angiotensin II receptor blockers (n=2088), calcium channel blockers (n=937), angiotensin converting enzyme inhibitors (n=665), β blockers (n=195), and diuretics (n=155). About half of the patients who were prescribed an antihypertensive drug had stopped taking it within one year. On any day, patients who were still engaged with the drug dosing regimen omitted about 10% of the scheduled doses: 42% of these omissions were of a single day’s dose, whereas 43% were part of a sequence of several days (three or more days—that is, drug “holidays”). Almost half of the patients had at least one drug holiday a year. The likelihood that a patient would discontinue treatment early was inversely related to the quality of his or her daily execution of the dosing regimen.Conclusions Early discontinuation of treatment and suboptimal daily execution of the prescribed regimens are the most common facets of poor adherence with once a day antihypertensive drug treatments. The shortfalls in drug exposure that these dosing errors create might be a common cause of low rates of blood pressure control and high variability in responses to prescribed antihypertensive drugs.     

Randomised Trial of Text Messaging on Adherence to Cardiovascular Preventive Treatment (INTERACT Trial)

Background

About one third of patients prescribed blood pressure or lipid-lowering drugs for the prevention of coronary heart disease and stroke do not take their medication as prescribed. We conducted a randomized trial to evaluate text messaging as a means of improving adherence to cardiovascular disease preventive treatment.

Methods

303 patients taking blood pressure and/or lipid-lowering medications were randomly assigned to being sent text messages (Text group, 151) or not being sent them (No text group, 152). Texts were sent daily for 2 weeks, alternate days for 2 weeks and weekly thereafter for 22 weeks (6 months overall), using an automated computer programme. Patients were asked to respond on whether they had taken their medication, whether the text reminded them to do so if they had forgotten, and if they had not taken their medication to determine if there was a reason for not doing so. At 6 months, use of medication was assessed.

Results

Two patients were lost to follow-up, providing data on 301 for analysis. In the No text group 38/151 (25%) took less than 80% of the prescribed regimen (ie. stopped medication completely or took it on fewer than 22 of the last 28 days of follow-up) compared to 14/150 patients (9%) in the Text group – an improvement in adherence affecting 16 per 100 patients (95% CI 7 to 24), p<0.001. The texts reminded 98/151 patients (65%) to take medication on at least one occasion and lead to 20/151 (13%) who stopped taking medication because of concern over efficacy or side-effects, resuming treatment.

Conclusions

In patients taking blood pressure or lipid-lowering treatment for the prevention of cardiovascular disease, text messaging improved medication adherence compared with no text messaging.

Trial Registration

Controlled-Trials.com ISRCTN74757601     

Adherence to Antihypertensive Therapy and Elevated Blood Pressure: Should We Consider the Use of Multiple Medications?

Background

Although a majority of patients with hypertension require a multidrug therapy, this is rarely considered when measuring adherence from refill data. Moreover, investigating the association between refill non-adherence to antihypertensive therapy (AHT) and elevated blood pressure (BP) has been advocated.

Objective

Identify factors associated with non-adherence to AHT, considering the multidrug therapy, and investigate the association between non-adherence to AHT and elevated BP.

Methods

A retrospective cohort study including patients with hypertension, identified from a random sample of 5025 Swedish adults. Two measures of adherence were estimated by the proportion of days covered method (PDC≥80%): (1) Adherence to any antihypertensive medication and, (2) adherence to the full AHT regimen. Multiple logistic regressions were performed to investigate the association between sociodemographic factors (age, sex, education, income), clinical factors (user profile, number of antihypertensive medications, healthcare use, cardiovascular comorbidities) and non-adherence. Moreover, the association between non-adherence (long-term and a month prior to BP measurement) and elevated BP was investigated.

Results

Non-adherence to any antihypertensive medication was higher among persons < 65 years (Odds Ratio, OR 2.75 [95% CI, 1.18–6.43]) and with the lowest income (OR 2.05 [95% CI, 1.01–4.16]). Non-adherence to the full AHT regimen was higher among new users (OR 2.04 [95% CI, 1.32–3.15]), persons using specialized healthcare (OR 1.63, [95% CI, 1.14–2.32]), and having multiple antihypertensive medications (OR 1.85 [95% CI, 1.25–2.75] and OR 5.22 [95% CI, 3.48–7.83], for 2 and ≥3 antihypertensive medications, respectively). Non-adherence to any antihypertensive medication a month prior to healthcare visit was associated with elevated BP.

Conclusion

Sociodemographic factors were associated with non-adherence to any antihypertensive medication while clinical factors with non-adherence to the full AHT regimen. These differing findings support considering the use of multiple antihypertensive medications when measuring refill adherence. Monitoring patients'' refill adherence prior to healthcare visit may facilitate interpreting elevated BP.     

Factors Associated with Medication Adherence among Patients with Schizophrenia in Mekelle,Northern Ethiopia

Background

Non-adherence to antipsychotic medication has a negative impact on the course of illness resulting in increased risk of relapse, rehospitalization and suicide, and increased costs to healthcare systems. The objective of this study was to investigate factors associated with medication adherence among patients with schizophrenia at Ayder Referral Hospital and Mekelle Hospital in Mekelle, Tigray region, Northern Ethiopia.

Methods

The study was a cross-sectional survey in which sociodemographic characteristics, drug attitudes, insight and side effects were measured and explored in terms of their relationship with medication adherence. A structured questionnaire as a data collection tool was used. Data were analyzed with the help of SPSS Version 20.0.

Results

A total of 393 patients participated, 26.5% were non-adherent to their antipsychotic medication. The factors significantly associated with better adherence were positive treatment attitudes (AOR = 1.40, 95% CI: 1.26, 1.55), fewer side effects (AOR = 0.97, 95% CI: 0.94, 0.99), awareness of illness (AOR = 1.44, 95% CI: 1.12, 1.85) and the ability to relabel symptoms (AOR = 1.57, 95% CI: 1.19, 2.07). However, khat chewers (AOR = 0.24, 95% CI: 0.09, 0.68), being illiterate (AOR = 0.13, 95% CI: 0.03, 0.47) and older age group (AOR = 0.03, 95% CI: 0.01, 0.16) were associated with less medication adherence.

Conclusions

A high prevalence of medication non-adherence was found among patients with schizophrenia. Intervention strategies focused on educating the patients to better understand the illness, medications and their potential side effects might be useful in improving adherence to antipsychotic medication treatment.