Cumulative Incidence and Factors Associated With Surgical Site Infections in a Hospital Cohort (2011–2025)

Surgical site infections (SSIs) are a relevant complication, with potential negative impacts on patient recovery and hospital costs. Their occurrence may be influenced by patient-related factors, the contamination potential of the procedure, the surgical specialty involved, and the hospital where surgery was performed. This work aims to describe the cumulative incidence of SSI in a cohort over 14 years (2011–2025) and to evaluate possible associated factors. Retrospective cohort, built from accumulated data from active surgical surveillance by the infection control committee of two hospitals with different levels of complexity, during hospitalization and up to 30 days after the procedure. Cumulative SSI incidence was calculated, and logistic regression was performed. The final statistical model was adjusted for age, sex, hospital type, and contamination potential. Surgical specialty was included as a categorical explanatory variable in the model. The cumulative incidence of SSI was 8.84% in surgeries with active follow-up up to 30 days (n = 87,858) and 7.3% considering all surgeries performed (n = 106,492). Patient age showed a positive association with SSI occurrence (OR = 1.004; 95% CI: 1.0026–1.0054; p < 0.001). Surgeries classified as contaminated or infected had a 66% higher chance of evolving with SSI compared with clean surgeries (OR = 1.66; 95% CI: 1.55–1.78; p < 0.001). Patients operated on in the secondary hospital had a significantly lower risk of SSI (OR = 0.55; 95% CI: 0.50–0.60; p < 0.001). Specialties were compared with each other, using general surgery as the reference. Cardiac surgery stood out with a significantly higher SSI risk (OR = 8.34; 95% CI: 1.14–60.90; p = 0.037), while Ophthalmology showed an inverse association (OR = 0.089; 95% CI: 0.012–0.676; p = 0.019). The findings reinforce the importance of active surveillance stratified by specialty and type of surgery, and indicate the relevance of contextual factors such as hospital type and inherent procedural risk for SSI occurrence. This information can guide more effective infection prevention and control policies in surgical settings.