Characteristics of IgA nephropathy in advanced-age patients.

Abstract

The susceptible age for IgA nephropathy (IgAN) is <30 years. However, IgAN sometimes develops in people aged >60 years, and its characteristics remain unknown. We divided 600 IgAN patients into three groups: advanced-age group (AAG, n=31, ≥60 years); middle-aged group (MAG, n=162, 40-59 years); and young-aged group (YAG, n=407, 20-39 years). We analyzed clinical and histological background, renal outcome, and risk of progression. In the AAG, mean arterial pressure (MAP) and the number of hypertensive patients were significantly higher than in the YAG. Total protein, serum albumin, and estimated glomerular filtration rate were significantly lower, and blood urea nitrogen, proteinuria, and N-acetyl-β-D-glucosaminidase were significantly higher in the AAG than in MAG and YAG. In histological findings, interstitial fibrosis/tubular atrophy by Oxford classification and arteriosclerosis were more severe in the AAG than the in YAG. Renal survival rate analyzed by Kaplan-Meier method was significantly lower in the AAG (22.9%/19 years in the AAG vs. 69.2 and 84.9%/20 years in the MAG and YAG, p<0.0001). The patients who progressed to end-stage renal disease (ESRD) in the AAG had higher MAP and more severe proteinuria compared with the patients who did not progress to ESRD in the AAG. The characteristics of IgAN in advanced-age were lower renal function, high levels of proteinuria, severe interstitial change, and arteriolosclerosis caused by glomerulopathy and concomitant diseases, such as hypertension, dyslipidemia, and hyperuricemia. Prognosis was poor, and >70% developed ESRD within 20 years.