Variation in antibiotic prescribing costs in Danish general practice: an epidemiological pharmaco-economic analysis

Based on 49,621 prescriptions during a period of 6 months we analysed factors relevant to the use of antibiotics among 137 general practitioners based on the reimbursement by the Danish Health Service. The background population constituted 167,105 adults and 42,392 children. The Danish Health Service refunds either 50 or 75% of the costs of antibiotics. The mean reimbursement per prescription was 96.45 DKK ranging between 56.10 DKK and 141.95 DKK. The total prescribed amount of antibiotics per GP measured in defined daily dose (DDD), the reimbursement per prescription for all other drugs than antibiotics, the proportion of patients above the age of 65 years and the number of cultures per 1,000 patients were positively associated with the reimbursement per prescription of antibiotics. The four variables explained 29% of the variation. The number of cultures and consultations per general practitioner were positively associated with the total reimbursement for antibiotics per general practitioner, while the number of throat swabs per general practitioner was negatively associated. The prescribed amount of DDD per prescription and the reimbursement per DDD of antibiotics contributed almost equally to the variation in reimbursement for each prescription. The study thus shows that the doctors prescribing the highest amounts of antibiotics measured as DDD also choose the most expensive drugs and that this choice of expensive drugs seems to be a general trend independent of the ATC group.