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

BACKGROUND: This 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.

METHODS: This 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.

RESULTS: The 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).

CONCLUSIONS: For 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.