Kidney Disease Progression in Membranous Nephropathy among Black Participants with High-Risk APOL1 Genotype

Abstract

Visual Abstract

Background 

Disparity in CKD progression among Black individuals persists in glomerular diseases. Genetic variants in the apolipoprotein L1 (APOL1) gene in the Black population contribute to kidney disease, but the influence in membranous nephropathy remains unknown.

Methods 

Longitudinally followed participants enrolled in the Glomerular Disease Collaborative Network or Cure Glomerulonephropathy Network were included if they had DNA or genotyping available for APOL1 (Black participants with membranous nephropathy) or had membranous nephropathy but were not Black. eGFR slopes were estimated using linear mixed-effects models with random effects and adjusting for covariates and interaction terms of covariates. Fisher exact test, Kruskal–Wallis test, and Kaplan–Meier curves with log-rank tests were used to compare groups.

Results 

Among 118 Black membranous nephropathy participants, 16 (14%) had high-risk APOL1 genotype (two risk alleles) and 102 (86%) had low-risk APOL1 genotype (zero or one risk alleles, n=53 and n=49, respectively). High-risk APOL1 membranous nephropathy participants were notably younger at disease onset than low-risk APOL1 and membranous nephropathy participants that were not Black (n=572). eGFR at disease onset was not different between groups, although eGFR decline (slope) was steeper in participants with high-risk APOL1 genotype (−16±2 [±SE] ml/min per 1.73 m² per year) compared with low-risk APOL1 genotype (−4±0.8 ml/min per 1.73 m² per year) or membranous nephropathy participants that did not identify themselves as Black (−2.0±0.4 ml/min per 1.73 m² per year) (P<0.0001). Time to kidney failure was faster in the high-risk APOL1 genotype than low-risk APOL1 genotype or membranous nephropathy participants that were not Black.

Conclusions 

The prevalence of high-risk APOL1 variant among Black membranous nephropathy participants is comparable with the general Black population (10%–15%), yet the high-risk genotype was associated with worse eGFR decline and faster time to kidney failure compared with low-risk genotype and participants that were not Black.