[Clinicopathological study of IgA nephropathy: the influence of age on renal histological changes and prognosis]

Clinicopathological features and prognosis were studied in 291 Japanese patients (4 to 60 years of age) with IgA nephropathy to investigate the influence of age on this disease. Histological assessment was done using the semiquantitative scoring system consisting of the activity index (A1) and chronicity index (C1). 1) Cl scores, especially global glomerulosclerosis and tubulointerstitial change, markedly increased with age, while Al scores slightly increased. 2) The Cl scores and rate of chronic renal failure (CRF) increased, especially in patients beyond 30 years of age. 3) A higher rate of CRF or regular hemodialysis was found in patients with Cl > or = 4 compared to those with Cl < 4 (21.7%, 2.9% respectively). These results suggest that chronic, irreversible histologic changes increase with age, especially beyond the age of 30 years, which worsens the prognosis of patients with IgA nephropathy.