Distribution of Biopsy-Proven Presumed Primary Glomerulonephropathies in 2000-2011 Among a Racially and Ethnically Diverse US Population

Background: The incidence and distribution of primary glomerulonephropathies vary throughout the world and by race and ethnicity. We sought to evaluate the distribution of primary glomerulonephropathies among a large racially and ethnically diverse population of the United States. Study Design: Case series from January 1, 2000, through December 31, 2011. Setting & Participants: Adults (aged >= 18 years) of an integrated health system who underwent native kidney biopsy and had kidney biopsy findings demonstrating focal segmental glomerulosclerosis (FSGS), membranous glomerulonephritis (MGN), minimal change disease (MCD), immunoglobulin A nephropathy (IgAN), and other. Outcomes: Rates and characteristics of the most common primary glomerulonephropathies overall and by race and ethnicity. Results: 2,501 patients with primary glomerulonephropathy were identified, with a mean age 50.6 years, 45.7% women, 36.1% Hispanics, 31.2% non-Hispanic whites, 17.4% blacks, and 12.4% Asians. FSGS was the most common glomerulonephropathy (38.9%) across all race and ethnic groups, followed by MGN (12.7%), MCD (11.0%), IgAN (10.2%), and other (27.3%). The FSGS category had the greatest proportion of blacks, and patients with FSGS had the highest rate of poverty. IgAN was the second most common glomerulonephropathy among Asians (28.6%), whereas it was 1.2% among blacks. Patients with MGN presented with the highest proteinuria (protein excretion, 8.3 g) whereas patients with FSGS had the highest creatinine levels (2.6 mg/dL). Overall glomerulonephropathy rates increased annually in our 12-year observation period, driven by FSGS (2.7 cases/100,000) and IgAN (0.7 cases/100,000). MGN and MCD rates remained flat. Limitations: Missing data for urine albumin and sediment, indication bias in performing kidney biopsies, and inexact classification of primary versus secondary disease. Conclusions: Among a racially and ethnically diverse cohort from a single geographical area and similar environment, FSGS was the most common glomerulonephropathy, but there was variability of other glomerulonephropathies based on race and ethnicity. (C) 2016 The Authors. Published by Elsevier Inc. on behalf of the National Kidney Foundation, Inc.