IgA nephritis with nephrotic range proteinuria.

Nephrotic range proteinuria is uncommon in patients with IgA nephritis. For this reason we compared the clinical and pathologic features in 63 non-nephrotic patients with those in 8 patients who had nephrotic range proteinuria at the time of biopsy. Both the mean age and the mean duration of the disease at the time of diagnosis were not significantly different in the 2 groups of cases. Significant associations were found between nephrotic range proteinuria and the following: the extent of glomerular hyalinization, the severity of interstitial fibrosis and tubular atrophy and the degree of foot process effacement and mesangial matrix increase. A significant association was also noted with nephrotic range proteinuria had elevated levels of serum creatinine on follow-up compared with 20% of non-nephrotic cases. The results of our study suggest that patients with nephrotic range proteinuria have a more severe type of IgA nephritis from the outset and that a marked degree of proteinuria is not merely a consequence of the duration of disease.