Medication Errors and Potentially Inappropriate Medication Use in Elderly Patients Admitted to the General Internal Medicine Outpatient Clinic of a University Hospital

Background: The frequency of chronic diseases, number of drugs used, and number of medication errors have increased in the elderly. In this study, we aimed to determine the prevalence of potentially inappropriate medication (PIM) use and medication errors in elderly patients admitted to a university hospital and to identify the influencing factors. Material and Methods: In this prospective cross-sectional study, the patients’ characteristics, drug use patterns, and medication errors in the previous month were recorded in detail. Following this, PIM use was assessed according to the 2015 Beers Criteria. Results: A total of 721 elderlay patients (60.9% female and 39.1% male) were included in this study. The mean number of drugs used by the patients per day was 4.6±2.8 and the rate of polypharmacy was 49.4%. The rate of medication errors was 54.2%, that of PIM use was 30.1%, and that of adverse drug reactions was 22.5%; these rates were higher in patients with polypharmacy. The most common medication error, PIM use, and adverse drug reaction were the omission of a daily dose (36.5%), inappropriate use of proton pump inhibitors (10%), and gastrointestinal system-related symptoms (7.7%), respectively. Diabetes mellitus and depression were found to be independent factors associated with medication errors. Conclusions: In the present study, patient-related medication errors, PIM use, and adverse drug reactions were more frequently observed in elderly patients with polypharmacy. In addition, medication errors were more commonly observed in elderly with diabetes mellitus and depression.