Association of Out-of-Pocket Pharmacy Costs with Adherence to Varenicline

BACKGROUND: Varenicline, a nicotinic acetylcholine receptor partial agonist, is a pharmacotherapy indicated for smoking cessation treatment. To date, no research has examined the relationship between out-of-pocket (OOP) expense and varenicline adherence among Medicare beneficiaries. OBJECTIVES: To (a) characterize medication utilization patterns of varenicline among Medicare members newly initiated on varenicline and (b) examine the relationship between member OOP expense and varenicline medication adherence. METHODS: In this retrospective cohort study, pharmacy claims data were used to identify Medicare Advantage Prescription Drug Plan (MAPD) members newly initiated on varenicline. Demographic and clinical characteristics, varenicline medication utilization patterns, and pharmacy costs (total and varenicline-specific) were determined for members included in the study. Varenicline adherence was measured by calculating the proportion of days covered (PDC) over a period of 84 days (12 weeks) after initiatio...