Nomogram for the prediction of crescent formation in IgA nephropathy patients: a retrospective study

Background The 2017 Oxford classification of immunoglobulin A nephropathy (IgAN) recently reported that crescents could predict a worse renal outcome. Early prediction of crescent formation can help physicians determine the appropriate intervention, and thus, improve the outcomes. Therefore, we aimed to establish a nomogram model for the prediction of crescent formation in IgA nephropathy patients. Methods We retrospectively analyzed 200 cases of biopsy-proven IgAN patients. Least absolute shrinkage and selection operator(LASSO) regression and multivariate logistic regression was applied to screen for influencing factors of crescent formation in IgAN patients. The performance of the proposed nomogram was evaluated based on Harrell’s concordance index (C-index), calibration plot, and decision curve analysis. Results Multivariate logistic analysis showed that urinary protein ≥ 1 g (OR = 3.129, 95%CI = 1.454–6.732), urinary red blood cell (URBC) counts ≥ 30/ul (OR = 3.190, 95%CI = 1.590–6.402), mALBU ≥ 1500 mg/L(OR = 2.330, 95%CI = 1.008–5.386), eGFR < 60ml/min/1.73m 2 (OR = 2.295, 95%CI = 1.016–5.187), Serum IgA/C3 ratio ≥ 2.59 (OR = 2.505, 95%CI = 1.241–5.057), were independent risk factors for crescent formation. Incorporating these factors, our model achieved well-fitted calibration curves and a good C-index of 0.776 (95%CI [0.711–0.840]) in predicting crescent formation. Conclusions Our nomogram showed good calibration and was effective in predicting crescent formation risk in IgAN patients.