Assessment of prolonged hospital stay attributable to surgical site infections using appropriateness evaluation protocol

Background: The accepted standard in estimating the stay prolongation attri butable to surgical site infections is the matched-cohort study method (MCS ), which is associated with selection bias. The Appropriateness Evaluation Protocol (AEP) has been used to estimate stay prolongation attributable to nosocomial infections bur has not been validated specifically for surgical site infections. Aim of the study: To compare estimates of stay prolongation attributable to surgical site infections after digestive surgery, obtained by AEP and by M CS. Methods: Sixty-five surgical site infections after digestive tract surgery were analyzed by AEP and MCS. AEP stay prolongation was the number of days judged specifically appropriate for the care of surgical site infections. M CS stay prolongation was the difference of stay duration in surgical site i nfection cases and two controls matched by age, sex, and diagnosis-related groups. Sensitivity and specificity of AEP, and agreement between both meth ods, were calculated. Results The mean AEP stay prolongation was 3.5 days vs 7.2 days for MCS. Th e sensitivity of AEP was 58% and the specificity was 75%. The agreement bet ween the two methods was poor. Conclusion: Surgical site infections after digestive tract surgery increase d the hospital stay. Accurate estimations of a prolongation of stay will va ry according to the method selected.