Objective: To quantify the frequency of potentially inappropriate medication (PIM) prescribing for outpatients aged 65 years and older using claims data of a German statutory health insurance.
Methods: Based on the 2002 Beers criteria for PIM use, a retrospective evaluation of drug prescription data in outpatient care was conducted for the years 2003 and 2004 using data from a German statutory health insurance (AOK) in the area of Saxony. The study was limited to those drugs classified as being potentially inappropriate according to the criteria independent of existing medical conditions and without any restrictions concerning dosage or duration of use, because this information was not available from the data.
Results: In 2003, 3.3% (408,375) of all 12,513,584 drug prescriptions for patients 65 years and older which were analyzed included a PIM from the Beers list. In 2004, it was 2.9% (297,524) of 10,126,809 (p < 0.001). The most frequently prescribed PIMs were short-acting nifedipine (13.4%), indomethacin (12.3%) and diazepam (11.8%) in 2003, and diazepam (14.6%) followed by indomethacin (13.7%) and doxazosin (10.9%) in 2004. 21.7% (119,482) and 18.2% (98,465) of patients 65 years or older received at least one prescription of a PIM in 2003 and 2004, respectively (p < 0.001). In a multivariate logistic regression model female gender and a higher number of prescribed drugs were significantly associated with an increased frequency of receiving a PIM in both years.
Conclusions: In our study, approximately every 5th older patient was prescribed at least one PIM. For the future an ongoing update of the Beers criteria to further include newer agents and an adaptation to the different situation in European countries is desirable.