Incidences of membranous nephropathy versus focal segmental glomerulosclerosis: increase in the former or decline in the latter?

Abstract

During the last three decades of the 20th century, a significant development in the field of glomerular diseases was an increased frequency of focal segmental glomerulosclerosis (FSGS) among patients presenting with proteinuria and a primary glomerular disease [1–10]. This increase in FSGS, initially noted in Chicago and other urban areas of the USA [1–7], was subsequently documented in rural areas of the USA and outside of North America [8–10]. The increase was reported in both adults and children and in different racial and ethnic groups, although the greatest overall incidence of FSGS was consistently found in individuals of African descent [1–5, 7, 11–13]. As a result, over a period of 20–30 years, FSGS overtook membranous nephropathy (MN) as the leading cause of nephrotic-range proteinuria in American adults when all races were considered [3, 4, 6] (Table 1). Furthermore, by the early 1990s, two independent studies from Chicago found FSGS to account for 50–70% of African-American adults with nephrotic-range proteinuria [3, 4].