A CROSS-SECTIONAL STUDY TO EXPLORE THE PRESCRIBING OF DRUGS WITH POTENTIAL DRUG GENE INTERACTIONS IN IRISH PRIMARY CARE

Johnson, Laura; Youssef, Essra; O'Shea, Joseph; Ledwidge, Mark; Thornley, Tracey; Gallagher, Joseph; Ryan, Cristin

Abstract

Background and Objective: Pharmacogenetics (PGx) is being increasingly recognised as a strategy for medicines optimisation and prevention of adverse drug reactions. According to guidelines produced by the Clinical Pharmacogenetics Implementation Consortium (CPIC)1 and the Dutch Pharmacogenetic Working Group (DPWG),2 most drugs with drug-gene interactions (DGIs), are prescribed in primary care. The aim of this study was to estimate the prevalence of potential and actionable DGIs involving drugs prescribed in primary care in Ireland.

Method: A large primary care database (the Health Service Executive Primary Care Reimbursement Service (HSEPCRS), which details all prescribing to patients who have a means tested General Medical Services (GMS) card), was analysed to estimate the national prevalence of total prescribing and incidence of first time prescribing of 42 drugs with potential DGIs according to the CPIC and/or DPWG guidelines, for the year 2021 (01/01/21 - 31/12/21). Phenotype frequency data from the UK Biobank3 and the CPIC were used to estimate the incidence of actionable DGIs.

Main outcome measures: The main outcome measures were (i) the overall prevalence of prescribing of medicines with potential DGIs, and (ii) the prevalence of actionable DGIs.

Results: A potential DGI was present in 17.3% (n = 10,830,871) of 62,754,498 medicines prescribed to GMS patients in 2021, 15.7% (n = 1,700,187) of which were prescribed to patients for the first time. Upon application of phenotype frequencies, 21.4% (n = 2,313,080) and 21.5% (n = 366,103) of total prescribing and instances of first time prescribing with potential DGIs were actionable. Compulsory changes in prescribing (dose adjustment or drug alternative) were recommended for 41.4% (n = 957,342) and 37.5% (n = 137,341) of total and first-time prescribings with an actionable DGI. The remainder of recommendations entailed increased monitoring, guarding against maximum doses, or an optional drug/dose change. Actionable DGIs were most commonly identified for antidepressants, weak opioids, and statins.

Conclusion: There is a high prevalence of potential and actionable DGIs in primary care. This study identifies areas of primary care prescribing that have the greatest opportunity for medicines optimisation to support the implementation of pharmacogenetic screening programme. The role of targeted PGx testing needs to be further explored and future research should follow patient-reported and clinical outcomes upon implementation of such a programme to evaluate its clinical utility and impact on patient care.

References: 1. Clinical Pharmacogenetics Implementation Consortium (CPIC) [Available from: https://cpicpgx.org/.] Accessed on: 12 February 2023.
2. Pharmacogenomics guidelines (DPWG) [Available from: https://www.knmp.nl/media/1058.] Accessed on: 12 February 2023.
3. McInnes G, Lavertu A, Sangkuhl K, Klein TE, Whirl‐Carrillo M, Altman RB. Pharmacogenetics at scale: an analysis of the UK Biobank. Clinical Pharmacology & Therapeutics. 2021;109(6):1528-37.

Citation

Johnson, L., Youssef, E., O'Shea, J., Ledwidge, M., Thornley, T., Gallagher, J., & Ryan, C. (2023, October). A CROSS-SECTIONAL STUDY TO EXPLORE THE PRESCRIBING OF DRUGS WITH POTENTIAL DRUG GENE INTERACTIONS IN IRISH PRIMARY CARE. Poster presented at ESCP Aberdeen Symposium 2023: Innovations in Clinical Pharmacy Practice, Education and Research, Aberdeen, UK

• Presentation Conference Type: Poster
• Conference Name: ESCP Aberdeen Symposium 2023: Innovations in Clinical Pharmacy Practice, Education and Research
• Conference Location: Aberdeen, UK
• Start Date: Oct 30, 2023
• End Date: Nov 2, 2023
• Deposit Date: Oct 30, 2023
• Public URL: https://nottingham-repository.worktribe.com/output/26798770
• Related Public URLs: https://escpweb.org/escp_events/aberdeen-symposium-2023/
• Additional Information: Poster presented at the ESCP Aberdeen Symposium 2023: Innovations in Clinical Pharmacy Practice, Education and Research