The ratio of serum C-reactive protein level on postoperative day 3 to day 2 is a good marker to predict postoperative complications after laparoscopic radical gastrectomy for gastric cancer

PURPOSE: Study reported that C-reactive protein (CRP) would peak at 48 h after the initiation of an acute inflammatory response. We proposed that the ratio of CRP level on postoperative day 3 to day 2 (POD3/2 CRP) can be used to early predict major postoperative complications (PCs) for patients who underwent laparoscopic radical gastrectomy. METHODS: Patients were randomized into training cohort and validation cohort at a ratio of 7:3. PCs greater than grade II or more, according to Clavien-Dindo classification, were defined as major PCs. Three predictive models for major PCs based on CRP level were constructed, including POD3/2 CRP, the CRP level on POD3 (POD3 CRP), and the ratio of CRP level on POD3 to POD1 (POD3/1 CRP). The performances of three prediction models were assessed by AUC. Univariate and multivariate logistic regression analyses were performed to identify risk factors of major PCs. RESULTS: 344 patients were included. Major PCs were observed in 57 patients (16.6%). In the training cohort, POD3/2 CRP provided the best diagnostic accuracy with an AUC of 0.929 at an optimal cut-off value of 1.08, and the sensitivity and specificity were 0.902 and 0.880, respectively. In the validation cohort, the corresponding AUC was 0.917. BMI ≥ 25 kg/m(2) and POD3/2 CRP > 1 were identified as risk factors for major PCs. CONCLUSION: POD3/2 CRP is a reliable marker to predict major PCs after laparoscopic radical gastrectomy. If CRP is higher on POD3 than on POD2, major PCs are highly likely. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00423-022-02469-w.