The cost-effectiveness of cefepime plus metronidazole versus imipenem/cilastatin in the treatment of complicated intra-abdominal infection

Background: Our objective was to compare the economic benefits of cefepime plus metronidazole with those of imipenem/cilastatin in the treatment of complicated intra-abdominal infections. Methods: We used a retrospective analysis of clinical outcomes and health resource utilization data collected during a randomized, double-blind, multi-center clinical trial. Seventeen university-affiliated hospitals in the United States and Canada participated, as did 323 patients with complicated intra-abdominal infections. Decision analysis was conducted using a decision node of cefepime vs. imipenem, and chance nodes that included an Acute Physiology and Chronic Health Evaluation (APACHE) II score of ≤15 versus >15; a need for post-treatment surgical procedures; and clinical outcomes. Effectiveness of treatment was measured by differences in the length and cost of hospital stays, the number and cost of surgical procedures after treatment, cure rates, and the cost of antibiotics. Also evalulated were the incremental costs of cure (i.e., the costs of additional cures). Results: Comparing cefepime plus metronidazole with imipenem/cilastatin, the expected cost of patient care was $8,218 versus $10,414, respectively, and the cost-effectiveness ratio per cure was $10,058 versus $13,685. For severely ill patients (APACHE II score > 15), the expected cost was $12,962 versus $23,153, and the cost-effectiveness ratio per cure was $15,321 versus $64,313. Conclusions: Cefepime plus metronidazole was more cost-effective than imipenem/cilastatin in the treatment of complicated intra-abdominal infections, primarily because of fewer post-treatment surgical procedures and shorter hospital stays. The primary advantage accrued to severely ill patients who had an APACHE II score > 15.