Pharmacist-led deprescribing in older adults with cancer in ambulatory clinics: A sustainable QI initiative.

42 Background: Polypharmacy in older adults is associated with increased risk of adverse drug events, toxicity, hospitalizations, and mortality. Patients receiving cancer treatment may be particularly vulnerable to the risks of polypharmacy. Deprescribing - the process of reducing, discontinuing, or adjusting medications that are unnecessary or potentially harmful – can improve patient quality of life, decrease treatment toxicity, and reduce healthcare costs. Identification and optimization of polypharmacy in older adults is a priority outlined in the ASCO geriatric oncology guidelines. Methods: We aimed to reduce polypharmacy in at least 50% of eligible patients by March 2025 using quality improvement methodology. Eligible patients were those aged 65 years and older, prescribed 5 or more medications, and who were receiving outpatient anti-cancer treatments. Deprescribing was integrated into the existing pharmacy medication reconciliation workflow. Interventions were communicated directly to the patient and/or prescriber with clinical rationale provided. Deprescribing success - our primary outcome - was evaluated 3 months post intervention by patient confirmation and/or review of provincial pharmacy records. Adverse events were evaluated 6 months post intervention by chart review. Results: We present results from the first two Plan-Do-Study-Act (PDSA) cycles. Between April 1st, 2024, and January 31st, 2025, 40 patients (mean age 78.0 +/- 6.9 years) were identified, taking an average of 7.6 +/- 2.6 medications per patient, of which 1.6 +/- 1.0 were deemed potentially inappropriate. Statins (22%), antihypertensives (11%) and proton pump inhibitors (11%) were the most commonly deprescribed medication classes of the 63 interventions. Medications were mostly discontinued (84%) rather than changed (16%), with ineffective/unnecessary drug therapy (41%) being the most common rationale. At the 3-month follow-up, 65% of patients had at least one successful intervention, with 57% of inappropriate medications successfully deprescribed. Minor adverse events potentially related to deprescribing occurred in 14% of accepted interventions. The leading reason for unsuccessful interventions was prescriber disagreement (67%). Conclusions: Pharmacist-led deprescribing successfully reduced polypharmacy in 65% of selected older patients receiving cancer care in British Columbia. This initiative resulted in 57% of inappropriate medications being deprescribed, with a 14% rate of minor adverse events potentially related to the intervention.