Chi Wang, Wan He, QingYuan Zheng, Yuan Zhong, Meng Tang, ChunYing Zhang, Yong He
This routine urinalysis-based model may serve as an accessible laboratory-based risk stratification tool for identifying patients with relatively low or elevated predicted probability of IgAN in real-world hospital settings. It should be interpreted as an adjunct to clinical evaluation rather than as a stand-alone diagnostic test or replacement for renal biopsy.
BACKGROUND: IgA nephropathy (IgAN) is the most common primary glomerular disease worldwide. Routine urinalysis is universally accessible but underutilized for IgAN risk stratification. This study aimed to develop and validate a urinalysis-based risk stratification model for IgAN in a multicenter real-world hospital population.
METHODS: This retrospective multicenter study was based on routine urinalysis records from 8 hospitals. A total of 354 patients had biopsy-confirmed primary IgAN, and 18,002 controls had no documented IgAN diagnosis after electronic medical record (EMR) review. The dataset was randomly divided into a training cohort (70%) and a hold-out validation cohort (30%). LASSO penalized logistic regression was used for variable selection. Model performance was evaluated by discrimination, calibration, and decision curve analysis (DCA). Bootstrap validation with 1000 resamplings was performed. An 8-variable simplified model was additionally developed.
RESULTS: LASSO regression selected 13 variables for the primary full model. The primary model achieved an AUC of 0.849 (95% CI: 0.824-0.873) in the training cohort and 0.861 (95% CI: 0.833-0.890) in the validation cohort. Calibration was good in the training cohort (Brier score = 0.017), while moderate calibration deviation was observed in the validation cohort (Brier score = 0.020). The model yielded a high negative predictive value (>0.99). The 8-variable simplified model retained favorable discrimination with a validation AUC of 0.840.
CONCLUSIONS: This routine urinalysis-based model may serve as an accessible laboratory-based risk stratification tool for identifying patients with relatively low or elevated predicted probability of IgAN in real-world hospital settings. It should be interpreted as an adjunct to clinical evaluation rather than as a stand-alone diagnostic test or replacement for renal biopsy.