DDD-costs have a strong influence on antibacterial drug prescription in Germany: a differentiated correlation analysis from 1985 to 2022.

Antibacterial drugs are vital in modern medicine, and understanding the factors influencing their prescriptions is essential for maintaining their effectiveness and accessibility. This study investigates the hypothesis that costs significantly impact the prescriptions of antibacterial drugs, a factor previously underrecognized. To investigate this, we conducted correlation analyses on defined daily dose (DDD-) prescriptions and DDD-costs for the 15 most prescribed antibacterial drugs in Germany in 2022, using data from the Arzneimittelverordnungsreport (Drug Prescription Report) (1985-2022). The analysis focused on the periods 1985-2022, 1985-2011, and 2012-2022. Our findings revealed significant correlations between DDD-prescriptions and -costs for nearly all drugs over the entire period (1985-2022), with strong negative correlations for amoxicillin (- 0.941), cefuroxime axetil (- 0.900), clindamycin (- 0.800), nitrofurantoin (- 0.895), and cefaclor (- 0.819). From 1985 to 2011, only significant negative correlations were observed. In 2012-2022, significant correlations included both negative and positive, with strong positive correlations for ciprofloxacin (0.950) and clarithromycin (0.962). Overall, DDD-costs showed a persistent and strong correlation with DDD-prescriptions, particularly in the earlier period. This influence appears to diminish slightly in recent years, suggesting other factors might become more significant as DDD-costs plateau. Notably, amoxicillin, amoxicillin clavulanic acid, and nitrofurantoin consistently exhibited strong cost-prescription correlations throughout the entire period. While correlation does not imply causation, the significant and strong correlations, coupled with logical explanations, support the hypothesis that costs are a primary factor in prescribing patterns. Further research is needed to establish causality and examine other potential systemic factors affecting antibacterial drug prescriptions.