Glomerular disease frequencies by race, sex and region: results from the International Kidney Biopsy Survey

Abstract

Background: Large-scale studies comparing glomerular disease frequencies across continents are lacking.

Methods: We surveyed 29 nephropathology laboratories in four continents using a standardized data collection form. We obtained recent consecutive kidney biopsy diagnosis frequencies at each center and summary demographics for each diagnosis. This report focuses on glomerular disease frequencies by region and race/ethnicity.

Results: Among 42 603 glomerular disease diagnoses reported (median age 47 years, 52% male, 57% white), from a total of 60 340 diagnoses, glomerular disease subtype frequencies differed considerably by continent. Diabetic glomerulosclerosis (GS; 19.1%) and focal segmental glomerulosclerosis (FSGS; 19.1%) predominated in North America; lupus nephritis (38.1%) and FSGS (15.8%) predominated in Latin America; IgA nephropathy (IgAN; 22.1%) and FSGS (14.9%) predominated in Europe; and IgAN (39.5%) and lupus nephritis (16.8%) predominated in Asia. After stratifying by race, diabetic GS (17.4% versus 4.3%, P < 0.001) and FSGS (17.3% versus 11.8%, P < 0.001) were more, and lupus nephritis less (15.8% versus 45.6%, P < 0.001), frequent among Latinos in North versus Latin America; FSGS was more (13.1% versus 7.1%, P < 0.001), and IgAN less (27.4% versus 40.5%, P < 0.001), frequent among Asians in North America versus Asia; and FSGS (18.9% versus 13.5%, P < 0.001) and diabetic GS (18.7% versus 6.5%, P < 0.001) were more, and IgAN less (14.4% versus 25.4%, P < 0.001), frequent among whites in North America versus Europe.

Conclusions: We determined that glomerular disease frequencies differed by continent, even among patients of similar race/ethnicity. Regional environmental and lifestyle factors, and local biopsy policies, might influence glomerular disease epidemiology independently of race/ethnicity.

FIGURE 1

Glomerular disease subtype kidney biopsy frequencies, by geographic region, showing the 13 most common glomerular disease diagnoses only. CAN, Canada; LAM, Latin America; HSP, Henoch Schonlein purpura; C3GP, C3 glomerulopathy; TMA, thrombotic microangiopathy; TTP, thrombotic thrombocytopenic purpura; HUS, hemolytic uremic syndrome.

FIGURE 2

Glomerular disease subtype kidney biopsy frequencies, by race, comparing regions of ancestral origin to USA/Canada. Showing the 13 most common glomerular disease diagnoses only. *P < 0.004. HSP, Henoch Schonlein purpura; C3GP, C3 glomerulopathy; TMA, thrombotic microangiopathy; TTP, thrombotic thrombocytopenic purpura; HUS, hemolytic uremic syndrome.

FIGURE 3

Male sex frequencies among glomerular disease subtypes. Remaining patients female (missing sex excluded). *P < 0.002. ^#0.002 < P < 0.05. NOS, not otherwise specified; TMA, thrombotic microangiopathic anemia; TTP, thrombotic thrombocytopenic purpura; HUS, hemolytic uremic syndrome; GBM, glomerular basement membrane; C3GP, C3 glomerulopathy; MIDD, monoclonal immune deposition diseases; HSP, Henoch Schonlein purpura. ‘Other GN’ includes diagnoses with <100 cases overall (diffuse mesangial sclerosis, Finnish type congenital nephrotic syndrome, immunotactoid glomerulopathy, collagenofibrotic glomerulopathy, fibronectin glomerulopathy, IgM nephropathy, polyarteritis nodosa, preeclampsia/eclampsia, Fabry disease, lipoprotein glomerulopathy, sickle cell glomerulopathy).