Polypharmacy among 200 000 subjects of the population-based German National Cohort Study (NAKO), aged 19–74

BACKGROUND: Polypharmacy is associated with adverse events, impaired quality of life, and increased mortality, but population-based studies that include both prescribed and over-the-counter (OTC) drugs are scarce. METHODS: We analyzed baseline data from the German National Cohort Study (NAKO), Germany's largest population-based cohort study (recruitment 2014-2019, subjects aged 19-74 at baseline). We determined the prevalence of polypharmacy (defined as the reported regular use of ≥5 prescribed or OTC drugs) and hyperpolypharmacy (≥10 drugs), stratified by sex and age. Determinants of polypharmacy were estimated with logistic regression. RESULTS: Out of 203 765 subjects (mean age 49.8 years, 50.4% female), polypharmacy was present in 6869 women (6.7%, 95% confidence interval [6.5%; 6.8%]) and 8126 men (8.0% [7.9%; 8.2%]), hyperpolypharmacy in 505 women (0.5% [0.45%; 0.54%]) and 722 men (0.7% [0.67%; 0.77%]). Both were more prevalent at older ages. Diabetes mellitus and chronic cardiovascular conditions were strong determinants of polypharmacy, and cardiovascular drugs were the most commonly reported type. CONCLUSION: Polypharmacy was common in the NAKO, particularly in older subjects, men, and people with cardiovascular disease. The appropriateness of drug use could not be assessed in this study. Future studies should examine inappropriate polypharmacy and evaluate risk factors and deprescribing strategies.