Prevalence of pharmacogenomically implicated prescriptions in multi-ethnic populations in Singapore.

Combined frequency of CPIC level A or A/B drug prescriptions and actionable variants in CYP2C19, CYP2D6 and SLCO1B1 in a multi-ethnic population.

The authors linked 2014-2021 electronic health records from Singapore's National University Hospital, serving about 6% of the population, with published whole-genome sequencing data from 9,051 Singaporeans. Among 1,157,359 unique patients, 38.1% to 43.0% of those with prescriptions received at least one pharmacogenomically implicated medicine each year, with minimal variation by year, sex or ethnicity. The most frequently prescribed drugs were omeprazole, statins and tramadol, and the most implicated genes CYP2C19, CYP2D6 and SLCO1B1. Men, and Indian and Malay patients, were exposed earlier in life than women and Chinese patients. From variant frequencies, the authors estimate 18.4% of patients could have had their prescriptions modified by pre-emptive genotyping.

Synthesis written by Geno'X. For the full original abstract, please refer to the source publication.

The useful figure here is not the 40% exposure to a pharmacogenomic drug — found in nearly every study of this type — but the 18.4% of prescriptions actually modifiable, which gives a tangible basis for health-economic modelling. The ethnicity breakdown is the real contribution: Asian allele frequencies make a panel calibrated on European populations inadequate. One caveat: the 18.4% figure is a modelled estimate linking prescriptions and allele frequencies from two distinct populations, not a measurement in genotyped patients.

Analysis by Dr Thibaut Benquey