Dispensing of actionable pharmacogenetic drugs among adults receiving cardiovascular disease medications in the Northern Netherlands: A serial cross-sectional study.

The extent of pharmacogenetic (PGx) drug dispensing among Dutch adults receiving medications for cardiovascular disease (CVD) is unknown. Using the University of Groningen IADB.nl pharmacy database, we performed a serial cross-sectional study (2019-2023) to estimate the annual prevalence of PGx drug dispensing and annual rates of initiation. We also identified the most dispensed PGx drug classes, most frequently associated genes, and the proportion of individuals with potential opportunities for reuse of PGx testing results. Adults on CVD medication treatment were defined as those with ≥2 prescriptions for the same CVD medication (ATC classes B01, C01, C03, C07-C10) within 180 days in a calendar year. PGx drugs were defined as drugs with actionable drug-gene interactions according to international CPIC or national DPWG guidelines. The annual cohort size ranged from 47,602 in 2019 to 41,846 in 2023 (mean age ~70 years; ~48% male). The prevalence of ≥1 PGx drug dispensing (~90%) and multiple (≥2) PGx drug dispensing (~68%) remained stable across 5 years, both increasing significantly with age. CVD-related PGx drugs were most common (75%), followed by proton pump inhibitors (55%). In 2023, CYP2C19, CYP2D6, and SLCO1B1-associated drugs had most users (60%, 53%, and 51%). Among those receiving drugs associated with CYP2C19, CYP2D6, and SLCO1B1, 24%, 23%, and 4% would have opportunities for reuse of testing results with single-gene testing, and 66%, 65%, and 83% with panel testing. In conclusion, PGx drug dispensing was highly prevalent among people receiving CVD medications, warranting further research into the (cost-)effectiveness of PGx testing.