VALUE OF PATHOLOGICAL GRADING IN PREDICTION OF RENAL SURVIVAL IN IGA NEPHROPATHY

In order to clarify the most reliable risk factor to predict renal out come, 206 patients with IgA nephropathy were studied for mean period o f 9.2 years. The histopathological changes of this disease using light microscopy were divided into four grades (grade 1-4). These grades in cluded glomerular, interstitial and vascular lesions. The cumulative r ate of kidney survival progressing to end stage renal failure (ESRF) i n 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 wa s 94% at 5 years, 79% at 10 years and 75% at 15 years. In grade 4 it w as 53% at 5 years, 33% at 10 years and 22% at 15 years after renal bio psy. 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 albu min; 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 re ciprocal of serum creatinine. These factors were: (i) the levels of to tal protein; (ii) the degree of our pathological grading; and (iii) th e amount of proteinuria. It was concluded that our pathological gradin g was useful as a prognostic parameter because of its simplicity and a vailability in routine clinical activities.