Cost effectiveness of ciprofloxacin plus metronidazole versus imipenem-cilastatin in the treatment of intra-abdominal infections

Objective: To compare the cost effectiveness of sequential intravenous (TV) to oral ciprofloxacin plus metronidazole (CIP/MTZ IV/PO) with that of IV ciprofloxacin plus IV metronidazole (CIP/MTZ IV) and IV imipenem-cilastatin (IMI IV) in patients with intra-abdominal infections. Design and participants: Patients enrolled in a double-blind randomised clinical trial were eligible for inclusion into this cost-effectiveness analysis, Decision analysis was used to characterise the economic outcomes between groups and provide a structure upon which to base the sensitivity analyses. 1996 cost values were used throughout. Setting: The economic perspective of the analysis was that of a hospital provider. Main outcome measures and results: Among 446 economically evaluable patients, 176 could be switched from IV to oral administration. The 51 patients randomised to CIP/MTZ IV/PO who received active oral therapy had a success rate of 98%, mean duration of therapy of 9.1 days and mean cost of $US7678. There were 125 patients randomised to either CIP/MTZ IV or IMI IV who received oral placebo while continuing on active IV antibacterials; their success rate was 94%, mean duration of therapy was 10.1 days and mean cost was $US8774_ (p = 0.029 vs CIP/MTZ IV/PO). Of the 270 patients who were unable to receive oral administration, 97 received IMI IV and had a success rate of 75%, mean duration of therapy of 13.8 days and a mean cost of $US 12 418, and 173 received CIP/MTZ IV and had a success rate of 77%, mean duration of therapy of 13.4 days and mean cast of $US 12 219 (p = 0.26 vs IMI IV). Conclusions: In patients able to receive oral therapy, sequential IV to oral treatment with ciprofloxacin plus metronidazole was cost effective compared with full IV courses of ciprofloxacin plus metronidazole or imipenem-cilastatin. In patients unable to receive oral therapy, no difference in mean cost was found between IV imipenem-cilastatin or IV ciprofloxacin plus IV metronidazole.