Real-World Utilization of Medications With Pharmacogenetic Recommendations in Older Adults: A Scoping Review

Pharmacogenetic testing provides patient genotype information which could influence medication selection and dosing for optimal patient care. Insurance coverage for pharmacogenetic testing varies widely. A better understanding of the commonly used medications with clinically important pharmacogenetic recommendations can inform which medications and/or genes should be prioritized for coverage and reimbursement in the context of finite healthcare resources. The aim of this scoping review was to collate previous studies that investigated the utilization rate of medications that could be guided by pharmacogenetic testing. Included studies utilized electronic medical records or claims data to assess pharmacogenetic medication prescription rates for older adults (≥ 65 years old). Identified pharmacogenetic medications were classified according to therapeutic class and assessed for actionability based on the Clinical Pharmacogenetics Implementation Consortium guidelines. Across the 31 included studies, analgesic (n = 29), psychotropic (n = 29), and cardiovascular (n = 27) therapeutic classes were most commonly investigated. Study populations were primarily generalized (48%); however, some studies focused on specific populations, such as, cancer (n = 6), mental health (n = 1), and nursing home (n = 2) cohorts. A total of 215 unique pharmacogenetic medications were reported, of which, 82 were associated with actionable pharmacogenetic recommendations. The most frequent genes implicated in potential drug-gene interactions with these actionable pharmacogenetic drugs were CYP2D6 (25.6%), CYP2C19 (18.3%), and CYP2C9 (11%). Medications most frequently prescribed included pantoprazole (range 0%-49.6%), simvastatin (range 0%-54.9%), and ondansetron (range 0.1%-62.6%). Overall, the frequently prescribed medications and associated genes identified in this review could guide pharmacogenetic testing implementation into clinical practice, including insurer subsidization.