Impact of pharmacist collaborative practice agreement on pharmacogenomic implementation for patients referred from geriatric medicine

BACKGROUND: Previously, patients referred from a geriatric clinic needed a pretest consultation with both the pharmacogenomics (PGx) pharmacist and clinical geneticist prior to testing. Results and recommendations had to also be reviewed by both individuals. This workflow led to delays in care and some patients being lost to follow up. A pharmacist collaborative practice agreement (CPA) was established to allow the PGx pharmacist to conduct the initial visit independently. The CPA goal was to decrease time for PGx results, medication changes, and potential symptom improvement. This study aimed to describe the effect of a CPA on PGx services in our geriatrics clinic. OBJECTIVES: The primary objective compared the times between referral placement and initial visit with the PGx pharmacist before (January 5, 2019-October 31, 2021) and after (January 1, 2022-May 31, 2023) CPA implementation. Key secondary objectives included rates of successful test completion and actionable results, baseline medication interventions, barriers for not completing testing, and proportion of potentially inappropriate medications (PIMs) discontinued within 6 months. METHODS: This was a retrospective cohort study of adults aged 60 years and older referred by the ambulatory geriatric clinic for PGx testing. RESULTS: Time to initial visit decreased by 39%, and over 30% of PIMs were discontinued within 6 months. Rates of successful completion and actionable results from PGx testing remained high. CONCLUSION: This study demonstrated a positive impact of implementing a CPA in a pharmacist-led PGx testing service.