Primary membranoproliferative glomerulonephritis on the decline: decreased rate from the 1970s to the 2000s in Japan

A prolonged change in the rate of primary membranoproliferative glomerulonephritis (MPGN) was identified using a Japanese database of renal biopsies.

We retrospectively investigated 6,369 renal biopsies that were performed between 1976 and 2009. Primary MPGN patients were selected, and the clinical and pathological findings were examined. We also statistically analyzed the changing rate of the onset of primary MPGN according to each decade.

Seventy-nine cases with primary MPGN (1.2 % of total biopsies) were diagnosed. The age of the patients ranged from 6–79 years (average 34.6 years). There were 24 children and 55 adults, including 37 male and 42 female patients. Thirty-six cases of primary MPGN (45.6 %) showed nephrotic syndrome—8 childhood and 28 adult cases. In the pathological classification of 44 samples using electron microscopy, 29 cases were MPGN type I, 1 case was MPGN type II, and 14 cases were MPGN type III. The secular change of the rate of primary MPGN onset showed a statistically significant reduction from the 1970s to the 2000s. The rate of primary MPGN onset in the child population also significantly decreased, but not in the adult population. Among the clinical parameters, disease severity and prognosis remained unchanged. Regarding treatment in recent years, steroid pulse therapy became more available but the administration of warfarin and anti-platelet drugs significantly decreased.

We concluded that the rate of total primary MPGN and that of pediatric patients with primary MPGN decreased.