(C44) Utilization of Drugs with Pharmacogenetic Dosing Recommendations in Children in Switzerland: a Descriptive Study Using Swiss Claims Data

Publication Number: 988

Background: The implementation of pharmacogenetics (PGx) is advancing in the adult population, but the potential for PGx testing in children is unclear.

Objectives: We aimed to assess the prevalence of PGx drugs in children in Switzerland, to identify the most frequently claimed PGx drugs and thereby the most relevant PGx genes.

Methods: We assessed the utilization of 82 drugs associated with pediatric guideline annotations linked to variants in 24 genes in the Pharmacogenomics Knowledge Base (PharmGKB) using Helsana claims data between 2017 and 2021. Helsana is a large Swiss health insurance that provides basic health insurance to approximately 1.2 million people per year, including approximately 19% children under the age of 18 years. We determined absolute and relative numbers of PGx drug exposure, and ranked the substances and associated genes based on the number of exposed children stratified by age and sex.

Results: From 2017 to 2021, in total 159’172 children were insured by Helsana, 48.6% were female. 93.8% of the children had at least 1 drug claim and 60.5% were exposed to at least 1 PGx drug during the 5-year observation period, 12.4% in infants ( < 1 year), 48.4% in toddlers (1 year), 53.4% in early childhood (2-4 years), 49.5% in middle childhood (5-10 years), and 45.4% in adolescence (11-17 years). Exposure prevalences were similar in boys and girls. 0.2% of all children had ≥5 PGx drugs, increasing with age from 0.0% in infants < 1 year, to 0.2% in adolescents (11-17 years). The top 3 PGx drugs were ibuprofen (53.7%), ondansetron (6.6%), and fluorouracil (6.2%) across the whole pediatric population. The exposure to PGx drugs from the alimentary tract and metabolism (infants: 1.3%, toddlers: 3.7%, early childhood: 6.2%, middle childhood: 6.0%, and adolescence: 9.0%) and the nervous system (infants: 0.1%, toddlers: 0.3%, early childhood:1.2%, middle childhood: 1.8%, and adolescence: 3.9%) increased with age. CYP2C9 (53.7%), CYP2D6 (10.2%), and DPYD (6.2%) were the top three drug-associated genes in children independent of sex. Seven genes (CYP2C9, CYP2D6, DPYD, CYP2C19, MT-RNR1, RYR1, and CACNA1S) were responsible for over 95% of all potential drug-gene-interactions.

Conclusions: The exposure to PGx drugs is high in children in Switzerland due to medications treating acute diseases, suggesting that a substantial number of children in Switzerland could benefit from pharmacogenetic testing.