Modified model for predicting early C-reactive protein levels after gastrointestinal surgery: A prospective cohort study

Background Postoperative serum concentration of C-reactive protein (CRP) is one of the objective quantitative indices integrating the effects of preoperative and intraoperative variables. Higher levels of CRP after gastrointestinal surgery are associated with major postoperative complications. To develop a model for predicting CRP levels on postoperative day (POD) 1 in surgical patients both with and without serious conditions and comorbidities, we modified the previous formula for prediction of CRP levels on POD1, and assessed the accuracy of our modified predictive formula for CRP levels. Material and methods Consecutive patients of all ages undergoing gastrointestinal surgery under general anesthesia were enrolled in this single-institution prospective cohort study. We developed a modified predictive formula in a calculation cohort. Next, associations between measured CRP levels on POD1, predicted CRP levels on POD1 using the previous and modified models, and major complications after surgery were examined in a validation cohort. Results We obtained the following model in the calculation cohort (n = 222): Modified model for predicting CRP levels on POD1 (mg•dL -1 ) = -10.13 + 0.0025 Duration of surgery (min) + 15.9 Mean Nociceptive Response (NR) + 0.66 Preoperative CRP level (mg•dL -1 ). In the validation cohort (n = 440), there was a significant association between measured and predicted CRP levels on POD1 ( P < 0.001) No significant difference between the measured and predicted CRP levels using the modified model was observed ( P = 0.847). There were also significant associations between the predicted CRP levels and major complications after surgery. Conclusion CRP levels predicted using duration of surgery, mean NR, and preoperative CRP levels are likely identical to measured CRP levels on POD1, being associated with major complications after gastrointestinal surgery.