Cost-effectiveness of ampicillin/sulbactam versus cefoxitin in the treatment of pelvic inflammatory disease

Objective: To determine whether ampicillin/sulbactam or cefoxitin is the more cost-effective antibiotic for treating women with acute pelvic inflammatory disease. Methods: A retrospective pharmacoeconomic analysis of a prospective, randomized clinical trial was conducted from the hospital perspective, comparing ampicillin/sulbactam to cefoxitin in the treatment of women with acute pelvic inflammatory disease. Cost-effectiveness analysis was used to characterize, measure, and compare costs and potential economic differences between treatment regimens. Sensitivity analysis was used to alter the key variables in the economic model to test the strength of the decision. Results: Seventy-six women treated with ampicillin/sulbactam (3 g intravenously (IV) every 6 hours) and 41 women treated with cefoxitin (2 g IV every 6 hours) evaluated for efficacy in the clinical trial comprised the economic analysis. The two groups were similar in demographic characteristics and adverse events. Ampicillin/sulbactam was more effective than cefoxitin (P = 0.05) in the clinical trial. The mean cost of treatment per patient in the ampicillin/sulbactam group, $4,940 was less than that in the cefoxitin group, $5,583 (P < 0.001). Sensitivity analyses varying drug acquisition cost or hospital per diem did not alter the economic decision; ampicillin/sulbactam was less costly than cefoxitin across all levels of cost comparison. Varying clinical success rates revealed that cefoxitin would need to be 7% more effective than ampicillin/sulbactam in order to change the economic decision in favor of cefoxitin. Conclusion: Ampicillin/sulbactam was cost-effective compared to cefoxitin for the treatment of acute pelvic inflammatory disease in this patient population.