Seasonal trends in surgical site infections after hernia repair

Surgical site infections (SSIs) after hernia repair are associated with longer hospital stays, increased readmission rates, and higher hospital costs. Patients undergoing colorectal and orthopedic surgeries during warmer months have been shown to have higher SSI risk. We investigated the relationship between season and SSI risk after hernia repair, hypothesizing that SSI risk is higher during warmer months. This retrospective cohort study used the American College of Surgeons (ACS) – National Surgical Quality Improvement Program (NSQIP) database to identify hernia repair patients from 2006 to 2021. We compared rates of any SSI between warm and cold seasons, defined based on admission quarter. Multi-variable and binomial logistic regression models were used to determine independent predictors of outcomes. Of the 826,636 patients in the final cohort, 400,329 (48.4%) underwent surgery in the warm operative season. Warm operative season was associated with increased odds of superficial [OR 1.15 95% CI 1.10–1.20] (+ 1.11 SSIs per 1000 cases) and any [OR 1.12 95% CI 1.08–1.16] SSI (+ 1.30 SSIs per 1000 cases) after adjusting for covariates. There was no difference between seasons for rates of deep incisional [OR 1.04 95% CI 0.96–1.13] and organ space [OR 1.02 95% CI 0.93–1.12] SSIs. Other independent predictors of any SSI included open surgical approach, groin hernia, non-elective case type, smoking, diabetes, and obesity. Patients undergoing hernia repair in warmer months have a higher risk of superficial SSI compared to those in colder months. Season may represent an under-explored SSI risk factor and warrants further study to identify modifiable mechanisms.