Patient Preference and Adherence (Sep 2017)
Out-of-pocket costs and adherence to antihypertensive agents among older adults covered by the public drug insurance plan in Quebec
Abstract
Raymond Milan,1 Helen-Maria Vasiliadis,2,3 Samantha Gontijo Guerra,1 Djamal Berbiche3 1Health Sciences Program, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 2Department of Community Health Sciences, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, 3Charles-Le Moyne Hospital Research Center, Longueuil, QC, Canada Objective: To evaluate the effect of patient out-of-pocket costs on adherence to antihypertensive agents (AHA) in community-dwelling older adults covered by the public drug insurance plan in Quebec. Methods: This is a secondary analysis of data from the “Étude sur la santé des aînés” study (2005–2008) on community-dwelling older adults in Quebec aged 65 years and older (N=2,811). The final sample included 881 participants diagnosed with arterial hypertension and treated with AHA. Medication adherence was measured with the proportion of days covered over a 2-year follow-up period (<80% and ≥80%). Out-of-pocket costs for AHA, in Canadian dollars (CAD), at cohort entry were categorized as follows: $0, $0.01–$5.00, $5.01–$10.00, $10.01–$15.00 and $15.01–$36.00. Multivariable logistic regression models were constructed to study adherence to AHA as a function of out-of-pocket costs while controlling for several confounders. Models were also stratified by annual household income (<$15,000 CAD and ≥$15,000 CAD). Results: In this study, 80.8% of participants were adherent to their AHA. Among participants reporting an annual household income <$15,000 CAD, those with an out-of-pocket cost of $10.01–$15.00 CAD were significantly less adherent to their AHA than those with no contribution (OR =0.175, 95% CI: 0.042–0.740). Among participants reporting an income of ≥$15,000 CAD, those with out-of-pocket costs of $0.01–$5.00 CAD (OR =0.194; 95% CI: 0.048–0.787), $5.01–$10.00 CAD (OR =0.146; 95% CI: 0.036–0.589), $10.01–$15.00 CAD (OR =0.192; 95% CI: 0.047–0.777) and $15.01–$36.00 CAD (OR =0.160, 95% CI: 0.039–0.655) were significantly less adherent to their AHA than participants with no contribution. Conclusion: Increased out-of-pocket costs are associated with non-adherence to AHA in older adults covered by a public drug insurance plan, more importantly in those reporting an annual household income ≥$15,000 CAD. A reduction in the amount of out-of-pocket costs and yearly maximum contribution for drugs may improve adherence to treatment. Keywords: medication adherence, seniors, hypertension, out-of-pocket costs, income
