To assess the cost-effectiveness of perioperative intranasal application of mupirocin calcium ointment in cardiothoracic surgery.

Cost-effectiveness analysis based on results of an intervention study with historical controls.

University Hospital Rotterdam, a tertiary referral center for cardiac and pulmonary surgery.

Consecutive patients undergoing cardiothoracic surgery between August 1, 1989, and February 1, 1991 (control group, n=928), and between March 1, 1991, and August 1, 1992 (intervention group, n=868).

Perioperative nasal application of mupirocin calcium ointment started on the day before surgery, continued for 5 days, twice daily.

Postoperative costs were increased significantly in patients with a surgical-site infection (SSI), compared with uninfected patients (P<.001). Mean SSI-attributable costs were estimated at $16,878 (95% confidence interval, $15,575-$18,181). The incidence of SSIs was 7.3% in the control group and 2.8% in the intervention group, mupirocin effectiveness being 62%. The costs of mupirocin were $11 per patient. Thus, the savings per SSI prevented were $16,633. To validate this comparative estimate of SSI-attributable costs, a noncomparative analysis of the postoperative length of stay (POLS) was performed, according to the Appropriateness Evaluation Protocol. Approximately 50% of the comparative SSI-attributable POLS were judged SSI-attributable in the noncomparative analysis. Sensitivity analyses, testing for the robustness of our conclusions, indicated that the presented model is rather insensitive to variations in the incidence of SSIs and for the effectiveness and costs of mupirocin. SSI-attributable costs were shown to be the only variable with substantial effect on the cost-effectiveness ratio. Perioperative mupirocin would result in net costs instead of savings only if SSI-attributable costs were less than $245.

SSIs in patients undergoing cardiothoracic surgery are associated with a substantial increase in postoperative costs. Provided that perioperative mupirocin reduces the SSI rate, this measure will be highly cost-effective in most centers providing cardiothoracic surgical services.