Drug-Drug Interactions in Nursing Home Residents With vs Without Dementia

To examine whether nursing home (NH) residents with Alzheimer's disease and related dementias (ADRD) are more likely than those without ADRD to be exposed to potential drug-drug interactions (DDIs) and to experience longer durations of exposure to DDIs.

Retrospective observational study.

Long-stay US NH residents.

We leveraged Medicare Fee-for-Service enrollment and claims data linked to Minimum Data Set 3.0 clinical assessments from 2018 to 2020 and identified NH residents aged ≥66 years with observable part D prescription drug data. We identified exposure to 98 potential DDIs during the duration of their NH stay. We described the number of DDIs with a clinically meaningful difference in prevalence and/or duration between groups, defined as a ≥1% difference in prevalence and ≥7 days' duration, respectively. We used a log-binomial model to estimate the association between ADRD and exposure to any DDI as an adjusted prevalence ratio with 95% CIs and predicted the marginal prevalence of exposure to any DDI for those with vs without ADRD, standardized to population covariate distributions.

We identified 485,251 eligible NH residents (average age, 84.6 [SD, 8.1] years; 67.1% female; 70.1% with ADRD; 56.6% with a potential DDI). A diagnosis of ADRD was associated with a higher prevalence of DDI exposure (prevalence ratio, 1.09 [95% CI, 1.08, 1.09]; marginal predicted prevalence for those with vs without ADRD: 58.0% vs 53.3%). Twelve DDIs had different prevalences between groups, and 34 DDIs had different differences in duration. For example, 29.6% of residents with vs 21.2% without ADRD were exposed to ≥3 central nervous system-active drugs.

NH residents with ADRD had a higher prevalence and duration of potential DDIs. Future research should evaluate whether the interactions we identified have causal effects on adverse outcomes such as falls.