Use of Drugs With Actionable Pharmacogenetic Biomarkers and Possible Prescribing Changes Among Older People

Pharmacogenetic testing offers a pathway to safer prescribing and improved outcomes in older adults, who face heightened risks of adverse drug reactions due to polypharmacy and age-related metabolic changes. This study evaluates the prevalence of actionable pharmacogenetic biomarker use and estimates the potential impact of genotype-guided dosing in Chinese older adults.

This retrospective cross-sectional analysis utilized 2015-2017 claims data from the China Health Insurance Research Association (CHIRA), encompassing 3,309,025 older patients (≥ 65 years) and 74,415,484 prescriptions. Drugs with Clinical Pharmacogenomics Implementation Consortium (CPIC) Level A evidence for actionable pharmacogenetic variants (n = 53) were identified. Key measures included the prescribing prevalence of Level A drugs and projected rates of actionable phenotype-driven dosing changes, calculated using population-specific genotype frequencies from PharmGKB and published sources.

Among older adults, 43.4% (433.8 per 1000) were prescribed ≥ 1 CPIC Level A drug. Atorvastatin (131.1 per 1000), omeprazole (124.3 per 1000), and clopidogrel (75.7 per 1000) were the most common. Over one-third (36.5%; 365.3 per 1000) of exposures required genotype-guided dose adjustments, with clopidogrel (CYP2C19) and statins (SLCO1B1) representing the highest-priority gene-drug interactions (259.6 and 221.8 per 1000, respectively).

CPIC Level A pharmacogenetic biomarkers are prevalent in Chinese older adults, with over 40% exposed to actionable gene-drug pairs and 36.5% requiring dose adjustments. These findings highlight the clinical imperative to integrate pharmacogenetic testing into geriatric care, prioritize CYP2C19 and SLCO1B1 testing, and develop region-specific guidelines to mitigate polypharmacy risks. Policymakers and clinicians should consider targeted implementation strategies to optimize prescribing safety and efficacy in aging populations.