Value of pathological grading in prediction of renal survival in IgA nephropathy

Summary: In order to clarify the most reliable risk factor to predict renal outcome, 206 patients with IgA nephropathy were studied for mean period of 9.2 years. the histopathological changes of this disease using light microscopy were divided into four grades (grade 1–4). These grades included glomerular, interstitial and vascular lesions. the cumulative rate of kidney survival progressing to end stage renal failure (ESRF) in all patients was 94% at 5 years, 87% at 10 years and 80% at 15 years after renal biopsy. None of the patients in grade 1 reached ESRF. the cumulative rate of kidney survival in grade 2 was 99% at 5 years, 98% at 10 years and 89% at 15 years after renal biopsy. In grade 3, it was 94% at 5 years, 79% at 10 years and 75% at 15 years. In grade 4 it was 53% at 5 years, 33% at 10 years and 22% at 15 years after renal biopsy. Forward stepwise multivariate regression analysis revealed that, in addition to the histopathological findings, three more risk factors were found to influence actuarial renal survival rate. These factors were: (i) the levels of serum creatinine; (ii) the level of serum albumin; and (iii) the amount of proteinuria at the time of renal biopsy. In parallel studies, forward stepwise multivariate regression analysis isolated three risk factors that influenced the progression of the reciprocal of serum creatinine. These factors were: (i) the levels of total protein; (ii) the degree of our pathological grading; and (iii) the amount of proteinuria. It was concluded that our pathological grading was useful as a prognostic parameter because of its simplicity and availability in routine clinical activities.