Clinical relevance of surgical site infection as defined by the criteria of the Centers for Disease Control and Prevention

Surgical site infection (SSI) is a common complication after abdominal surgery and the Centers for Disease Control and Prevention (CDC) criteria are commonly used for diagnosis and surveillance. The aim of this study was to evaluate whether SSI diagnosed according to CDC is clinically relevant (CRSSI) and whether there is agreement between evaluations according to the CDC criteria, the ASEPSIS score (Additional treatment, presence of Serous discharge, Erythema, Purulent exudate, Separation of the deep tissues, Isolation of bacteria and duration of Stay) and CRSSI. We included 54 patients diagnosed with SSI and a matched control group (N=46) without SSI according to the CDC criteria after laparotomy. Two blinded experienced surgeons evaluated the hospital records and determined whether patients had CRSSI, based on the following criteria: antibiotic treatment, surgical intervention, prolonged hospital stay or referral to an intensive care unit for SSI. The rate of CRSSI was 38 of 54 (70%) in patients with CDC-diagnosed SSI and none in patients without a CDC-diagnosed SSI. Sixty-one percent of the CDC-diagnosed SSIs were superficial, of which 48% were considered clinically relevant. There was substantial agreement between the CDC criteria and CRSSI [kappa=0.69; 95% confidence interval (CI): 0.55-0.83] and fair agreement between the ASEPSIS score and the CDC criteria (kappa=0.23; 95% CI: 0-0.49) and between the ASEPSIS score and CRSSI (kappa=0.39; 95% CI: 0.17-0.61). The CDC criteria represent a suitable standard definition for monitoring and identifying SSI, even if some cases of less clinically significant superficial SSI are included.