Polypharmacy, potentially inappropriate medication and pharmacogenomics drug exposure in the Rhineland Study

High medication use may contribute to the efficiency of drug therapy in general, but it could also increase the burden of adverse drug reactions. We aimed to assess medication use and the prevalence of three risk factors for adverse drug reactions: the use of polypharmacy, potentially inappropriate medication in the elderly and pharmacogenomic polymorphisms affecting the metabolism of drugs.

Cross-sectional interview-based medication data (including over-the-counter drugs) was collected in a large population-based cohort (≥30 years of age) in Bonn, Germany.

Analyses were based on the first 5000 participants of the Rhineland Study (mean age 55 years, 57% women). Of our participants, 66.0% reported the use of a drug regularly, which increased to 87.4% in participants aged ≥65 years (n = 1301). The rates of use of polypharmacy, potentially inappropriate medication and pharmacogenomic drugs were 15.9%, 6.4% and 20.5%, respectively. In participants <65 years, 16.0% (95% CI 14.8, 17.3) had at least one risk factor. In participants aged ≥65 years, 54.1% (95% CI 51.4, 56.8) had at least one and 27.4% (95% CI 25.0, 29.9) had at least two risk factors. Extrapolating these numbers to the German population implies that around 9 million of the 17 million individuals aged 65 years or older are potentially at an elevated risk for adverse drug reactions, of which 4.6 million are at a potentially highly elevated risk for adverse drug reactions.

Our study shows that drug use is common and the individual risk for an adverse drug reaction in our population is high. This suggests room for improvement in general medication use.