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

Abstract

To evaluate drug prescriptions and costs among diabetic patients in primary care practices in Germany. 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. Diabetic patients had an increased prescription use for most drugs. A substantial increased use (OR > or = 1.4) was found for cardiovascular drugs, fibrates, gout medication, laxatives, and wound care products. Diabetic subjects (7.9% of all patients) accounted for 21% of total annual prescription costs in the practices. Total costs (U.S. dollars) per patient-year were threefold higher (diabetic patients $384; control 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%). 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.