Discharge C-reactive protein predicts 90-day readmission after pancreatoduodenectomy: a conditional inference tree analysis

Abstract

BackgroundThe aim of this study was to assess the predictive value of discharge C-reactive protein (CRP) and white blood cell (WBC) levels for 90-day readmission after pancreatoduodenectomy (PD) and to determine cutoff values for detecting complications at discharge. MethodsA two-centre, retrospective study was performed between 2008 and 2022. Receiver operating characteristic (ROC) curve analysis was used to determine the predictive value of CRP level and WBC count at discharge. A conditional inference tree (CTREE) was constructed to identify combined risks within subgroups using variables associated with readmission. ResultsA total of 438 patients were included in the analysis. Of these, 54 (12%) were readmitted. The median WBC count at discharge was comparable between the readmitted and not readmitted groups (9.1 vs. 8.5 G/l). The CRP levels at discharge were predictive of 90-day readmission, with an area under the ROC curve (AUC) of 0.63 (95% CI: 0.55−0.63). A CRP concentration below 105 mg/l ruled out 90-day readmission, with a negative predictive value (NPV) of 90% (95% CI: 81%–95%). CTREE confirmed the diagnostic value of CRP at discharge (AUC = 0.68, 95% CI 0.60–0.68). CTREE additionally identified previous wound infection as a second risk factor for readmission in patients with CRP levels less than 101 mg/l (P = 0.003). The sensitivity, specificity, and NPV of CTREE were 52%, 90% and 97%, respectively. DiscussionCRP levels below 105 mg/l at discharge allow for a safe discharge with a low 90-day readmission rate. Furthermore, wound infection, but not WBC count, was a positive predictor of 90-day readmission with moderate accuracy, suggesting the need for predischarge imaging for undetected complications in this patient cohort. Trial registrationOur retrospective analysis did not require registration with a publicly accessible registry.