Polypharmacy in primary care practices: an analysis using a large health insurance database.

PURPOSE To ascertain the rate and range of continuous polypharmacy in German general practices and compare practice characteristics and prescribing profiles in practices with a high rate of polypharmacy patients (HPP) and a low rate of polypharmacy patients (LPP), respectively. METHODS This observational study used a database composed of prescription data from a large German statutory health insurance. We defined polypharmacy as the continuous prescription of five or more drugs and calculated the percentage of polypharmacy patients for each practice to identify HPP and LPP. RESULTS A total of 136 521 patients in 730 general practices received continuous medication. About 10% of these patients (14 293/136 521) received five or more different drugs. HPP had, on average, 15.1% polypharmacy patients compared to 4.2% in LPP. The total number of patients attending either a HPP or LPP was comparable (437 vs. 416; p = 0.102), but HPP had a higher number of patients with prescriptions (76.9% vs. 70.8%; p < 0.0001). The patients' age distribution was similar (68.0 in LPP vs. 68.8 in HPP) and there were slightly more female patients in LPP. Doctors in HPP prescribed proton pump inhibitors and NSAIDs more frequently than doctors in LPP, but there was no difference in the prescription of me-too drugs. CONCLUSION The absolute differences in age and gender distribution between HPP and LPP were modest. Prescribing quality, as measured by the rate of me-too drug prescriptions, was similar across all practices. Therefore, differences in the rate of polypharmacy in general practice cannot sufficiently be explained by these factors.