Long-term prognosis and prognostic indices of IgA nephropathy in juvenile and in adult Japanese.

For a comparative study of IgA nephropathy occurring in Japanese adolescents and adults, the clinical and histological findings and prognosis (follow-up period; 12 +/- 6 years for children and 10 +/- 5 years for adults) were compared. The subjects studied included 98 children and 86 adults. Development into renal failure occurred in 9 children (9.2%) and in 20 adults (23.3%), (p less than 0.01). The actuarial renal survival rate at year 10 after the onset of glomerulonephritis in children and adults was 95% and 80%, respectively, and at year 20, 82% and 50%, respectively. The prognosis was definitely better in the children and this was attributable to the observation that (1) the glomerular injury at the initial biopsy in children was less extensive than in adults; (2) the frequency of complication with hypertension was lower in children (27.6%) than in adults (41.9%), (p less than 0.05); (3) hypertension was one prognostic indice, even in children, after age 30; (4) after age 40, aging and arteriosclerosis were more contributory than hypertension to the progress of IgA nephropathy; and (5) the quantity of intraglomerular immune deposits and the period of deposition were not related of prognostic indices. Thus, in the long-term prognosis of IgA nephropathy in both children and adults, immunological disorders seem to have little influence while factors such as hypertension, arteriosclerosis and aging play important roles.