Long-term survival in idiopathic membranous glomerulonephritis: can the course be clinically predicted?

72 adult patients with idiopathic membranous glomerulonephritis (iMGN), 92% having proteinuria 3 g/24 h or more, were studied for the clinical evolution of the disease and factors which might be involved in the development of chronic renal insufficiency (CRI). At 10 years, 46% were in complete or partial remission, 4% had the nephrotic syndrome (NS), 26% had some degree of CRI, and 24% were dead or started on dialysis. The actuarial patient and kidney survival rates were 80% and 64%, respectively at 10 years. Patient survival rate was not affected by gender, age (after adjustment for age- and sex-matched population) or the severity of NS at diagnosis. 20 patients showed CRI and apart from the more frequent (p < 0.05) presence of CRI at diagnosis, no clinical features discriminated them from those having intact renal function. Furthermore, no clinical factors at diagnosis predicted the final renal function among the 72 patients. However, it appeared that the evolution of clinical status of iMGN was rapid CRI appearing 1.4 (median, range from 0 to 15.1) years after the diagnosis. At one and two years, renal function correlated significantly (r = 0.54, p < 0.0001 at two years) with the final renal function. What is more, the type of the evolution of proteinuria over the first two years gave valuable information on the eventual deterioration of renal function. Patients having stable non-nephrotic grade proteinuria and those in whom NS disappeared, had excellent renal outcome while those in particular showing an increased severity of NS had poor prognosis in terms of renal survival.(ABSTRACT TRUNCATED AT 250 WORDS)