(164) Prevalence of Drug-Drug Interactions in Older Community-Dwellers: A Systematic Review and Meta-Analysis

Publication Number: 838

Background: Polypharmacy is common in the older population and is associated with an increased risk of often preventable medication-related harm, including drug-drug interactions (DDIs). To date, an estimate of the overall DDI prevalence in older community-dwellers is unknown.

Objectives: To summarise DDI prevalence and identify common DDIs in older (≥65 years) community-dwelling adults.

Methods: PROSPERO: CRD42020216686. An electronic database search was conducted in PubMed and EMBASE. Observational studies published in English between 01/01/2010-10/05/2021 reporting DDI prevalence in community-dwellers aged ≥65 years were included. Nursing home and inpatient hospital studies were excluded. Articles were independently double screened for eligibility, differences were resolved by discussion. Data were independently extracted, 20% extracted in duplicate. Study authors were contacted if DDI prevalence data were not extractable. Quality assessment was independently performed by two reviewers using the Joanna Briggs Institute critical appraisal tool for prevalence studies. A meta-analysis of proportions was performed using a random-effects model with logit transformation and study participants as the unit of analysis. Heterogeneity was evaluated using I2 statistics and investigated using GOSH (graphic display of study heterogeneity) diagnostics and a priori subgroup analysis. DDI prevalence and 95% confidence intervals (CI) are presented. All analyses were performed using the metafor package (version 3.0.2) in R statistical software (version 4.1.2).

Results: 5144 unique articles were identified. Thirty-three studies involving 17,011,291 community-dwellers aged ≥65 years (age range 65-103) met inclusion criteria. Of the 33 studies included, 22 measured DDIs broadly classified as (potentially) clinically important. The method used to identify DDIs varied across studies: five used Micromedex®; three used the 2015 AGS Beers criteria®; three used Lexi-Interact®; two used drugs.com; six used multiple methods; and 14 used a single unique method. Thirty-one studies reported DDI prevalence at the study participant level, estimates ranged from 0.8% to 90.6%. Significant statistical heterogeneity precluded a full meta-analysis. Twenty-six studies were identified for qualitative synthesis and seven studies were eligible for meta-analyses. In a meta-analysis of three studies (N=1122) using Micromedex®, the pooled DDI prevalence was 57.8% (95% CI: 52.2, 63.2%; I2 69.6%, p<0.01). In a meta-analysis of two studies (N=809,113) using Lexi-Interact®, the pooled DDI prevalence was 30.3% (95% CI: 30.2, 30.4%; I2 6.8%). In a meta-analysis of two studies (N=947) using the 2015 AGS Beers Criteria®, the pooled DDI prevalence was 16.6% (95% CI: 5.6, 40.2%; I2 97.5%, p<0.01). Common DDIs frequently involved cardiovascular drugs.

Conclusions: DDIs are prevalent among older community-dwellers; however, the methodology used to estimate these events varies considerably. A standardised methodology is urgently needed to allow meaningful measurement of DDI prevalence in this growing and vulnerable population.