REDUCED OUT-OF-POCKET COSTS AND MEDICATION ADHERENCE ? A POPULATION-BASED STUDY

摘要

Background In 2007, a drug benefit plan for seniors (SDP) was launched in Saskatchewan, Canada. SDP capped out- of-pocket costs at $15 per prescription for individuals aged 65 and older. Objectives To quantify the impact of the SDP on chronic medication adherence. Methods A retrospective cohort study was conducted for participants aged 65 or older who were eligible to the SPD, controlled by a younger group aged 40 to 64 who were ineligible. Adherence was measured over 365 days using medication possession ratio (MPR). MPRs were compared between age groups, and between pre- and post SDP-launch periods. The odds ratio of optimal adherence (i.e., MPR≥80%) was estimated using logistic regression models with generalized estimating equations (GEE). Results Between 2005 and 2009, 353,568 adherence observations were observed from 188,109 unique patients. Comparing the post-SDP period vs before, the increase in the odds of optimal medication adherence was significant (OR = 1.08, 95% CI: 1.04 to 1.11) and was stronger after excluding patients already receiving medication benefits from other government programs (OR = 1.21, 95% CI: 1.16 to 1.26). The SDP was associated with improved adherence among the subgroup of prevalent medication users (OR = 1.08, 95% CI: 1.04 to 1.12), but not incident users (OR = 1.05, 95% CI: 0.98 to 1.13).ConclusionReducing out-of-pocket medication costs for seniors was associated with small improvements in medica-tion adherence across the population.