Predictive value of C-reactive protein for postoperative liver-specific surgical site infections

Background: C-reactive protein is a useful biological tool to predict infectious complications, but its predictive value in detecting organ-specific surgical site infection after liver resection has never been studied. We aimed to evaluate the predictive value of c-reactive protein and determine the cut-off values to detect postoperative liver resection-surgical site infection. Methods: A multicentric analysis of consecutive patients with liver resection between 2018 and 2021 was performed. The predictive value of postoperative day 1, postoperative day 3, and postoperative day 5 C-reactive protein levels was evaluated using the area under the receiver operating characteristic curve. Cut-off values were determined using the Youden index in a 500-fold bootstrap resampling of 500 patients treated at 3 centers, who comprised the development cohort and were tested in an external independent validation cohort of 166 patients at a fourth center. Results: Among the 500 patients who underwent liver resection of the development cohort, liver resection-surgical site infection occurred in 66 patients (13.2%), and the median time to diagnosis was 6.0 days (interquartile range, 4.0-9.0) days. Median C-reactive protein levels were significantly higher on postoperative day 1, postoperative day 3, and postoperative day 5 in the liver resection-surgical site infection group compared with the non-surgical site infection group (50.5 vs 34.5 ng/mL, 148.0 vs 72.5 ng/mL, and 128.4 vs 35.2 ng/mL, respectively; P < .001). Postoperative day 3 and postoperative day 5 C-reactive protein-level area under the curve values were 0.76 (95% confidence interval, 0.64-0.88, P < .001) and 0.82 (95% confidence interval, 0.72-0.92, P < .001), respectively. Postoperative day 3 and postoperative day 5 optimal cut-off values of 100 mg/L and 87.0 mg/L could be used to rule out liver resection-surgical site infection, with a negative predictive value of 87.0% (interquartile range, 70.2-93.8) and 76.0% (interquartile range, 65.0-88.0), respectively, in the validation cohort. Conclusion: Postoperative day 3 and postoperative day 5 C-reactive protein levels may be valuable predictive tools for liver resection-surgical site infection and aid in hospital discharge decision-making in the absence of other liver-related complications.