Steven Kozlowski, Ellen Tworkoski, Sai Dharmarajan, Natasha Flowers, Andrew Kwist, Shanlai Shangguan, Yoganand Chillarige, Michael Wernecke, Tom MaCurdy, Jeffrey A Kelman, David J Graham
PURPOSE: Pharmacy chains can differ with respect to the characteristics of their patient populations as well as their nonprescription products, services, and practices, and thus may serve as a surrogate for potential unmeasured confounding in observational studies of prescription drugs. This study evaluates whether a single-source drug can have different patient outcomes based on the dispensing pharmacy chain. METHODS: Separate analyses for two anticoagulant drugs, rivaroxaban and apixaban, were conducted using Medicare Fee-for-Service claims evaluating the association between dispensing pharmacy chain and outcomes of acute myocardial infarction, ischemic stroke, intracranial hemorrhage, gastrointestinal (GI) bleeding, all-cause mortality, and major GI bleeding...
February 2024: Pharmacoepidemiology and Drug Safety