A proposed Oxford classification-based clinicopathological nomogram for predicting short-term renal outcomes in IgA nephropathy after acute kidney injury

Abstract

BackgroundThis study aimed to investigate the effect of acute kidney injury (AKI) on the progression of renal disease and to develop a clinico-pathological nomogram to predict the renal outcome of IgA nephropathy (IgAN) patients, based on Oxford classification score. MethodsThis is a retrospective observational study. A total of 988 IgAN patients treated at our hospital between 2006 and 2011 were included and divided into AKI (n = 82) and non-AKI group (n = 906). The primary outcome measure was the composite renal endpoint. The secondary outcome measure was all-cause mortality. Clinical and pathologic features were assessed with multivariable Cox regression to predict the outcome in IgAN patients. A nomogram was developed to predict the renal outcome. ResultsThe median follow-up time was 48.6 months (range: 34.4 to 62.7). The incidence of AKI was 8.30%. The AKI group had more severe pathological characteristics and a significantly poor survival outcome than the non-AKI group. The multivariate Cox regression analysis showed that the AKI group had a 2.84 times higher risk of the composite renal endpoint as compared with the non-AKI group (P < 0.001). A clinico-pathological nomogram was developed using the seven predictors for the primary renal composite endpoint. The AUC for the nomogram model was 0.81 (sensitivity = 0.78, specificity = 0.85), and the C-index was 0.91 (95% CI = 0.85–0.97). ConclusionsFor IgAN patients, AKI is an independent risk factor for the progression of renal disease. Our nomogram model has good prediction power for the renal outcome of IgAN patients.