CHRONICITY INDEX AND MESANGIAL IGG DEPOSITION ARE RISK-FACTORS FOR HYPERTENSION AND RENAL-FAILURE IN EARLY IGA NEPHROPATHY

To determine the natural history in early immunoglobulin A (IgA) nephr opathy, we evaluated the long-term follow-up of 27 normotensive nonazo temic adult idiopathic IgA nephropathy patients with chronic hematuria who derived from a prospective regional epidemiological study of glom erulonephritis conducted between 1978 and 1984. As controls, 17 thin g lomerular basement membrane (GBM) patients, 24 patients with normal re nal tissue, and nine patients with miscellaneous nephropathies were fo llowed up. Median follow-up was 11 years (range, 8 to 14 years). Renal biopsies, performed within 2 years after patient identification, were scored semiquantitatively in terms of activity and chronicity indices , using a modified National Institutes of Health (NIH) scoring system. During follow-up, two patients with IgA nephropathy went into histolo gical remission, and 12 IgA nephropathy patients showed disease progre ssion, of whom three developed renal failure. Initial proteinuria over 1 g/d was associated with a high activity score, extracapillary lesio ns, and late onset of uremia. Mesangial IgG deposition and a higher in itial chronicity index were associated with development of hypertensio n during follow-up. In the multivariate analysis, a high initial chron icity index, erythrocyturia, and mesangial IgG deposition are independ ent determinants of progression of disease. We conclude that in patien ts with IgA nephropathy, identified early in the course of disease, er ythrocyturia, a high chronicity index, and mesangial IgG deposition in the presence of normal renal function are risk factors for decreased renal survival. Disappearance of hematuria is associated with remissio n of IgA nephropathy immunopathologically and low activity and chronic ity indices at initial biopsy. (C) 1998 by the National Kidney Foundat ion, Inc.