External validation of postoperative nausea and vomiting risk scores in patients with liver cancer: A single-centre prospective cohort study

Abstract

Objectives This study aimed to test the external validity of postoperative nausea and vomiting (PONV) risk assessment tools in patients undergoing hepatectomy, and to guide healthcare professionals’ assessment of postoperative patients. Background The identification of PONV risk is particularly important in the context of prevention. However, the predictive performance of the current PONV risk scores has not been confirmed in patients with liver cancer, and its applicability is still unknown. These uncertainties pose difficulties in performing routine risk assessment of PONV for patients with liver cancer in a clinical practice setting. Methods Patients diagnosed with liver cancer and undergoing hepatectomy were prospectively consecutively recruited. All enrolled patients received PONV assessments and PONV risk assessments via the Apfel risk score and the Koivuranta risk score. Receiver operating characteristic curves (ROC curves) and calibration curves were used to assess the external validity. This study was reported according to the TRIPOD Checklist. Results Among 214 PONV–assessed patients, 114 patients (53.3%) developed PONV. For the Apfel simplified risk score, the ROC area was 0.612 (95% confidence interval [CI]: 0.543–0.678) in the validation dataset, which demonstrated imperfect discrimination; the calibration curve showed poor calibration with a slope of 0.49. For the Koivuranta score, the ROC area was 0.628 (CI: 0.559–0.693) in the validation dataset, which showed limited discrimination; the calibration curve indicated an unsatisfactory calibration with a slope of 0.71. Conclusions The Apfel risk score and the Koivuranta risk score were not well validated in our study and disease-specific risk factors should be taken into account when updating or developing PONV risk stratification instruments.