Prevalence and predictors of polypharmacy among older primary care patients in Germany

Background. Older people consume an increasing amount of medication. Polypharmacy is associated with an elevated risk of adverse health outcomes resulting in hospitalizations and sometimes death. Objectives. To describe the prevalence of prescribed and over-the-counter (OTC) medications among older general practice patients living in the community. To determine predictors of polypharmacy (five or more prescribed drugs) from a variety of patient- and doctor-related factors. Methods. Sixty-seven randomly selected practices in two areas of Germany and 466 of their older patients (70+ years) were recruited for a geriatric assessment study. A cross-sectional analysis of health problems, GPs' awareness and their interventions was conducted. In this post hoc analysis, we assessed the medication use as reported by older patients and compared it with doctors' perceived medication regimens for their respective patients. The detailed assessment of patients' health and well-being enabled us to explore a variety of predictors of polypharmacy using logistic regression analysis with forward selection. Results. Study participants consumed an average of 3.7 prescribed medicines and an additional 1.4 OTC drugs. In all, 26.7% of patients used five and more chronically prescribed drugs. A set of five determinants predicted polypharmacy best: breathlessness, hypertension, dependency on instrumental activities of daily living, low subjective health and medication disagreement between doctors and patients. Conclusion. This older general practice population in Germany is among the top pharmaceutical user group of European study samples. Apart from disease-specific determinants, GPs should be aware that low subjective health and medication disagreement are independent predictors of polypharmacy.