Clinical course of immunoglobulin A nephropathy in children.

The clinical presentation, initial laboratory and renal biopsy findings, and subsequent clinical course of IgA nephropathy were studied retrospectively in 200 children, and findings in those with younger onset and older onset were compared. Eighty-three patients were 8 years of age or younger (group 1) and 117 were 9 years of age or older (group 2) at onset. There were no differences between the two groups with regard to sex, initial renal function, incidence of hypertension and macroscopic hematuria, degree of proteinuria, and pathologic findings. At the latest follow-up, two patients in group 1 and eight in group 2 had chronic renal failure, and five patients in group 1 and 21 in group 2 had heavy proteinuria with or without hypertension (P less than 0.01), whereas 36 (43%) patients in group 1 and 29 (25%) in group 2 had normal urine, blood pressure, and glomerular filtration rate (P less than 0.01); the disease followed a significantly more benign course in children with younger onset than in those with older onset. These observations suggest some age-related differences in the natural history of childhood IgA nephropathy.