Medication non-adherence leads to increased morbidity, mortality and treatment failures. Current literature lacks evidence about the effect of access to pharmacy services on medication adherence. Pharmacy desert (areas with low access to pharmacy services) may affect patient’s medication adherence behavior. This research aims to compare rates of medication adherence among elderly people living in pharmacy desert and non-desert areas in Pennsylvania for oral medications for treatment of type 2 diabetes mellitus.
We conducted a retrospective observational cohort study. The Pharmaceutical Assistance Contract for the Elderly (PACE) program claims dataset along with prescription drug event (PDE) data from Medicare Part D claims of the period January to June 2013 (N=15,886) was used to conduct this study. Medication adherence was measured as the Proportion of Days Covered (PDC) for subjects living in pharmacy desert and non-desert areas of Pennsylvania. PDC is defined as total day’s supply over total number of days evaluated multiplied by 100 and capped at 1. Patients with PDC ≥80% were dichotomized as adherent. Multiple regression analysis was carried out to examine the factors responsible for difference in medication adherence rates due to different access to pharmacy services.
Chester, Montgomery, Bucks, Delaware and Cumberland counties were considered as pharmacy desert areas (n=1771, Female=1376). Forest, Philadelphia, Fayette, Miffin and Sullivan counties were considered as pharmacy non-desert regions (n=943, Female=685). The mean of PDC for patients living in pharmacy desert and non-desert regions found to be 0.8 and >0.9 respectively. After adjusting for selected covariates, the income level, vehicle access, type of pharmacy services found to affect medication adherence rates among elderly patients living in pharmacy desert and non-desert areas.
Pharmacy deserts affect medication adherence rates among elderly patients. This suggests that by making greater efforts to increase access to pharmacy services, medication adherence may be increased.
© 2016 Published by Elsevier Inc.