Development and validation of a novel death risk stratification scale in patients with hemorrhagic fever with renal syndrome: a 14-year ambispective cohort study

ObjectivesTo develop and validate a simple and effective death risk stratification scale for hemorrhagic fever with renal syndrome (HFRS).MethodsIn this ambispective cohort study, we investigated the epidemiological and clinical data of 2245 HFRS patients (1873 enrolled retrospectively and constituting the training cohort, 372 prospectively recruited as the validation cohort) from September 2008 to December 2021, and identified independent risk factors for 30-day death of HFRS. Using logistic regression analysis, a nomogram prediction model was established and was further simplified into a novel scoring scale. Calibration plot, receiver operating characteristic (ROC) curve, net reclassification index (NRI), integrated discrimination index (IDI), and decision curve analysis (DCA) were used to assess the calibration, discrimination, precision, and clinical utility in both training and validation cohorts.ResultsOf 2245 HFRS patients, 132 (5.9%) died during hospitalization. The nomogram prediction model and scoring scale were developed using six predictors: comorbid hypertension, hypotensive shock, hypoxemia, neutrophils, aspartate aminotransferase, and activated partial thromboplastin time. Both the scale and nomogram were well calibrated (near-diagonal calibration curves) and demonstrated significant predictive values (areas under ROC curves >0.9, sensitivity and specificity >90% in the training cohort and >84% in the validation cohort). The simplified scoring scale demonstrated equivalent discriminative ability to the nomogram, with NRI and IDI of 0.022 and 0.007 in the training cohort, 0.126 and 0.022 in the validation cohort. DCA graphically represented significant clinical utility and comparable net benefits of the nomogram and scoring scale across a range of threshold probabilities.ConclusionsThis evidence-based, factor-weighted, accurate score could help clinicians swiftly stratify HFRS mortality risk and facilitate the implementation of patient triage and tiered medical services during epidemic peaks.