Prevalence of Drug–Drug Interactions in Older Community-Dwelling Individuals: A Systematic Review and Meta-analysis

BACKGROUND: Drug–drug interactions (DDIs) can lead to medication-related harm, and the older population is at greatest risk. We conducted a systematic review and meta-analysis to estimate DDI prevalence and identify common DDIs in older community-dwelling adults. METHODS: PubMed and EMBASE were searched for observational studies published between 01/01/2010 and 10/05/2021 reporting DDI prevalence in community-dwelling individuals aged ≥ 65 years. Nursing home and inpatient hospital studies were excluded. Study quality was assessed using the Joanna Briggs Institute critical appraisal tool. Meta-analysis was performed using a random-effects model with logit transformation. Heterogeneity was evaluated using Cochran’s Q and I(2). DDI prevalence and 95% confidence intervals (CIs) are presented. All analyses were performed in R (version 4.1.2). RESULTS: There were 5144 unique articles identified. Thirty-three studies involving 17,011,291 community-dwelling individuals aged ≥ 65 years met inclusion criteria. Thirty-one studies reported DDI prevalence at the study-participant level, estimates ranged from 0.8% to 90.6%. The pooled DDI prevalence was 28.8% (95% CI 19.3–40.7), with significant heterogeneity (p < 0.10; I(2) = 100%; tau(2) = 2.13) largely explained by the different DDI identification methods. Therefore, 26 studies were qualitatively synthesised and seven studies were eligible for separate meta-analyses. In a meta-analysis of three studies (N = 1122) using Micromedex(®), pooled DDI prevalence was 57.8% (95% CI 52.2–63.2; I(2) = 69.6%, p < 0.01). In a meta-analysis of two studies (N = 809,113) using Lexi-Interact(®), pooled DDI prevalence was 30.3% (95% CI 30.2–30.4; I(2) = 6.8%). In a meta-analysis of two studies (N = 947) using the 2015 American Geriatrics Society Beers criteria(®), pooled DDI prevalence was 16.6% (95% CI 5.6–40.2; I(2) = 97.5%, p < 0.01). Common DDIs frequently involved cardiovascular drugs, including ACE inhibitor-potassium-sparing diuretic; amiodarone-digoxin; and amiodarone-warfarin. CONCLUSIONS: DDIs are prevalent among older community-dwelling individuals; however, the methodology used to estimate these events varies considerably. A standardised methodology is needed to allow meaningful measurement and comparison of DDI prevalence. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40266-022-01001-5.