Prevalence of statin-drug interactions in older people: a systematic review

Statins are among the most frequently prescribed medications internationally. Older people are commonly prescribed multiple medications and are at an increased risk of drug-drug interactions, including statin-drug interactions. The aim of this study was to conduct a systematic review of current evidence on the prevalence of statin-drug interactions in older people.

A systematic search of observational studies in Embase, Medline, and PubMed was conducted. Articles were included if they were published in English during the period July 2000-July 2014 and reported on the prevalence of statin-drug interactions in people over 65 years of age. Two reviewers independently assessed the articles for eligibility and extracted the data.

The search returned 1556 eligible articles. A total of 19 articles met the inclusion criteria. In studies (n = 7) that focused on statin users only, the prevalence of potential statin-drug interactions assessed using different measures ranged from 0.19 to 33.0 %. In studies that examined drug interactions across a population of both statin users and non-users (n = 12), the prevalence of potential statin-drug interactions ranged from 0.1 to 7.1 % (n = 8), and the prevalence of clinically relevant statin-drug interactions ranged from 1.5 to 4 % (n = 4).

Current published evidence suggests substantial variations in the prevalence of statin-drug interactions and their clinical relevance. Further studies are necessary to provide a better understanding of the prevalence of clinically significant statin-drug interactions, the medications most frequently contributing to statin-drug interactions, and impact on relevant clinical outcomes in older people.