Polypharmacy after Discharge from Hospital: An Analysis Using Data of the Statutory Health Insurance (AOK) of Saxony-Anhalt

Introduction and Aim The growing number of people suffering from chronic diseases and multimorbidity is associated with an increased risk of polypharmacy. The aims of the study are to estimate the prevalence of polypharmacy and to analyse its determinants in the transition from in-to outpatient care. Furthermore, we estimate the risk of a potential inappropriate medication (PIM) and its determinants. Methods The analyses are based on the data of a German statutory health insurance (AOK Saxony-Anhalt) of the third quarter of 2009. The analyses include all insured persons aged 60 years and older who were discharged from hospital within the study period and had filled at least one prescription at the pharmacy (n = 21 041). After the analysis of prevalence rates of polypharmacy within 30 days after discharge from hospital, we used binary logistic regression models to estimate the effect of determinants of polypharmacy and PIM. In addition, interaction effects between the number of diseases and the number of practitioners involved in the therapy were calculated. Results Our analyses show a significant effect of the number of diseases and the number of practitioners on the risk of polypharmacy. Furthermore, patients who are treated with 5 or more drugs have a significantly higher risk of a PIM prescription. The interaction model illustrates a disproportional rise of polypharmacy risk in women with multiple chronic conditions with an increase in the number of doctors treating them. Conclusion The results suggest that polypharmacy is not a result of increasing morbidity alone. Furthermore, the remarkable effect of the number of physicians treating a patient points to an unsolved problem in communication and coordination in outpatient pharmacotherapy and shows the need for centralized medication monitoring.