Surgical site infection in patients submitted to orthopedic surgery: the NNIS risk index and risk prediction

The applicability of the risk index for surgical site infection of the National Nosocomial Infection Surveillance (NNIS) has been evaluated for its performance in different surgeries. In some procedures, it is necessary to include other variables to predict. Objective: to evaluate the applicability of the NNIS index for prediction of surgical site infection in orthopedic surgeries and to propose an alternative index. The study involved a historical cohort of 8236 patients who had been submitted to orthopaedic surgery. Statistical analysis was performed using multivariate logistic regression to fit the model. The incidence of infection was 1.41%. Prediction models were evaluated and compared to the NNIS index. The proposed model was not considered a good predictor of infection, despite moderately stratified orthopedic surgical patients in at least three of the four scores. The alternative model scored higher than the NNIS models in the prediction of infection.