IgA nephropathy in patients over 50 years of age: a multicentre, prospective study.

BACKGROUND: IgA nephropathy (IgAN) is considered as a disease of young men under 30 years of age. Findings on clinical and histological presentation and outcome in older patients have rarely been published.
METHODS: In a prospective cohort of IgAN patients, recruited over 3 years, 33 patients over age 50 were compared to 96 patients under age 50, according to clinical and histological findings. Actuarial renal survival rate was studied after a mean post-biopsy follow-up of 41 months.
RESULTS: Both groups of patients were comparable at baseline for frequency of proteinuria, microscopic haematuria and gross haematuria, but older patients had a significantly higher incidence of hypertension (65 vs 24%, P<0.01). Time between onset and diagnosis of IgAN was similar in both groups. Proteinuria/day, systolic blood pressure, and serum IgA levels were significantly higher, and Ccr was significantly lower in older patients at the time renal biopsy was performed, but serum creatinine and albumin were not. No difference was observed between the two groups for the presence of glomerular or tubulointerstitial lesions. Only endarteritis was significantly more common in older patients (75 vs 34%, P<0.01). End-stage renal failure (ESRF) was confirmed in five patients over 50 and 17 under 50. Renal actuarial survival curves did not show any significant difference between the two groups, even though the six patients who died were classified as ESRF.
CONCLUSIONS: When the histological diagnosis of IgAN was established, factors that carry a poor prognosis, i.e. proteinuria, high blood pressure, and decreased Ccr were more commonly present in patients over 50 than under 50. However, after the completion of a relatively short follow-up period, renal survival was identical in the two study groups. Prolonged follow-up is necessary to confirm this trend.