Surgical site infections (SSIs) are common surgical complications that lead to increased costs. Depending on payer type, however, they do not necessarily translate into deficits for every hospital.

We investigated how surgical site infections (SSIs) influence the contribution margin in 2 reimbursement systems based on diagnosis-related groups (DRGs).

This preplanned observational health cost analysis was nested within a Swiss multicenter randomized controlled trial on the timing of preoperative antibiotic prophylaxis in general surgery between February 2013 and August 2015. A simulation of cost and income in the National Health Service (NHS) England reimbursement system was conducted.

Of 5,175 patients initially enrolled, 4,556 had complete cost and income data as well as SSI status available for analysis. SSI occurred in 228 of 4,556 of patients (5%). Patients with SSIs were older, more often male, had higher BMIs, compulsory insurance, longer operations, and more frequent ICU admissions. SSIs led to higher hospital cost and income. The median contribution margin was negative in cases of SSI. In SSI cases, median contribution margin was Swiss francs (CHF) −2045 (IQR, −12,800 to 4,848) versus CHF 895 (IQR, −2,190 to 4,158) in non-SSI cases. Higher ASA class and private insurance were associated with higher contribution margins in SSI cases, and ICU admission led to greater deficits. Private insurance had a strong increasing effect on contribution margin at the 10th, 50th (median), and 90th percentiles of its distribution, leading to overall positive contribution margins for SSIs in Switzerland. The NHS England simulation with 3,893 patients revealed similar but less pronounced effects of SSI on contribution margin.

Depending on payer type, reimbursement systems with DRGs offer only minor financial incentives to the prevention of SSI.