Prescription drug use and costs among diabetic patients in primary health care practices in Germany

OBJECTIVE- To evaluate drug prescriptions and costs among diabetic patients in primary care practices in Germany. RESEARCH DESIGN AND METHODS- Computerized data on prescriptions and costs (drug company sales prices) were analyzed in 30,604 diabetic and 17,723 (5% random sample) nondiabetic patients from 362 primary care practices during 1994. Relative use ratios for drug groups were obtained from logistic regression models (odds ratio [OR] for diabetes) controlling for age, sex, and other covariates. Relative costs (diabetic:nondiabetic) were estimated by direct age and sex standardization. RESULTS- Diabetic patients had an increased prescription use for most drugs. A substantial increased use (OR greater than or equal to 1.4) was found for cardiovascular drugs, fibrates, gout medication, laxatives, and wound care products. Diabetic subjects (7.9% of all patients) accounted for 211 of total annual prescription costs in the practices. Total costs (U.S. dollars) per patient-year were threefold higher (diabetic patients $384, central subjects $123). After excluding antidiabetic agents and age- and sex-standardization, relative costs were still 1.5 times higher (P < 0.05). Diabetes treatment accounted for 24% of total costs in diabetic patients (insulin 12%; oral antidiabetics 6%). The most important cost factor was cardiovascular drugs (CVDs) (39%). Three CVD groups accounted for about 50% of total CVD costs in diabetic patients (ACE inhibitors 25%; Ca-antagonists 16%; nitrates 10%). CONCLUSIONS- Prescription use among diabetic patients in primary health care practices was predominantly increased for cardiovascular drugs and for treatment of diabetes-associated disorders. Diabetic patients accounted for over one-fifth of the total pharmacy costs in primary practices, indicating that diabetes is a major economic factor in drug use.