Using cost of infection as a tool to demonstrate a difference in prophylactic antibiotic efficacy: a prospective randomized comparison of the pharmacoeconomic effectiveness of ceftriaxone and cefotaxime prophylaxis in abdominal surgery.

The purpose of this study was to test the hypothesis that cost, as well as frequency of infection, could be used to demonstrate a difference in the performance of prophylactic antibiotics. In a prospective, randomized, double-blind study, 1013 patients undergoing abdominal surgery were given 1 g of intravenous ceftriaxone (R) or cefotaxime (C) at induction of anesthesia, and an additional 500 mg of metronidazole for colorectal surgery. Infection was checked for during the hospital stay and at 30 days postoperatively. The inpatient, outpatient, and community costs of infection were prospectively collected. The frequency of wound infection for appendectomies when additional metronidazole was not administered was greater with cefotaxime (R 6%, C 18%, p < 0.05), but the cost of infection was the same (average cost R $994 +/- SD $1101, C $878 +/- $1318). For all other procedures, the frequency of wound infection was similar (R 8%, C 10%), but the cost was less with ceftriaxone (R $887 +/- $1743, C $2995 +/- $6592, p < 0.05). Ceftriaxone decreased the frequency but not the cost of chest and urinary infection (frequency R 6%, C 11%, p < 0.02, cost R $1273 +/- 2338, C $1615 +/- 4083). Differences in both the frequency and cost of all infection are also presented. Ceftriaxone decreased either the frequency or the cost of different postoperative infections. The cost of infection can increase the discriminatory power of trials comparing antibiotic effectiveness.