Adverse Drug Reactions in Polypharmacy: A Real-World Pharmacovigilance Study Using EHR Data
Keywords:
Polypharmacy, Adverse Drug Reactions, Electronic Health Records, Pharmacovigilance, Drug-Drug InteractionsAbstract
Polypharmacy, commonly defined as the concurrent use of five or more drugs, is frequent in older and multimorbid patients and raises the risk of adverse drug reactions (ADRs). We conducted a retrospective cohort analysis using electronic health record (EHR) data from 2019-2023 to assess the incidence and risk factors of ADRs in a general medical population. We identified patients with polypharmacy (≥5 medications) and monitored ADRs through coded events and natural language processing of clinical notes. Logistic regression estimated the association of polypharmacy, drug classes, and drug-drug interactions (DDIs) with ADRs. In our sample of N patients (median age 68, 54% female), polypharmacy was present in about 58%. The overall ADR incidence was 14%, but was significantly higher in polypharmacy patients (19% vs 8%, p<0.001). Cardiovascular and antibiotic drug classes were most often implicated in ADRs. Notably, 18% of ADRs with multiple suspected drugs were due to confirmed DDIs, often involving anticoagulants and antiplatelets. After adjustment, polypharmacy (OR 2.4, 95% CI 1.8-3.2) and the number of medications (per drug OR 1.12, CI 1.08-1.17) were independent ADR risk factors. These results mirror prior findings in aging cohorts. Our study demonstrates that real-world EHR data can quantify ADR burden in polypharmacy and highlights the need for clinical monitoring and deprescribing strategies to prevent harm.
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