Differentiating Primary and Secondary FSGS Using Non‑Invasive Urine Biomarkers
Clinical Kidney Journal – 2023
Clinical Characteristics and Histopathology in Adults with Focal Segmental Glomerulosclerosis
Journal article
Published on November 27, 2023
Contributors:
Tuttle KR, Abner CW, Walker PD, et al.
Tuttle KR, Abner CW, Walker PD, et al.
DOI:
10.1016/j.xkme.2023.100748
10.1016/j.xkme.2023.100748
Summary
Evidence on focal segmental glomerulosclerosis (FSGS) histology from a large United States (US) biopsy‑based study1
Background
Focal segmental glomerulosclerosis (FSGS) is a common histological pattern of kidney injury that contributes to proteinuria and progression to kidney failure.1,2
There are multiple histological types of FSGS that correlate with variable clinical outcomes.1,3,4
Real-world evidence on the distribution and severity of FSGS histology at diagnosis across diverse populations remains limited.1
Aim
This study aimed to characterize FSGS histology patterns, their severity, and clinical correlates among United States (US) adults at the time of kidney biopsy.1
Approach
A retrospective analysis of kidney biopsies from adults diagnosed with FSGS between 2016 and 2020 was conducted using data from Arkana Laboratories.1
Histological variables included1:
- Global glomerulosclerosis (GS)
- Interstitial fibrosis and tubular atrophy (IFTA)
- Foot process effacement
- FSGS lesion type (tip, perihilar, cellular, collapsing, or not otherwise specified [NOS])
Findings
Demographics at kidney biopsy
Among 2,011 patients with FSGS, most were male (56.4%), and the overall mean age at biopsy was 49.1 ± 17.2 years.1 Compared with White patients (40.6%, 817/2,011), Black patients (23.6%, 474/2,011) were younger (52.8 vs. 45.5 years) and had lower eGFR (53.5 vs. 43.1 mL/min/1.73 m²).1
Severe histological features were common at diagnosis1
Global GS ≥50% and IFTA ≥50% were each observed in 1 in 5 kidney biopsies, while diffuse foot process effacement (≥80%) was seen in 47.3%.1
Severe FSGS histology was associated with Black race, advanced chronic kidney disease (CKD) stage, and nephrotic proteinuria1
Severe histological disease was more likely in Black vs. White patients (odds ratio [OR]: 2.46; 95% confidence interval [CI]: 1.59-3.79; P<0.001). The odds of severe histological disease were also associated with more advanced CKD (OR for stage 5 vs. stage 1-2: 22.59; 95% CI: 9.36-54.49; P<0.001).1
Diffuse foot process effacement was more common in those with nephrotic vs. non-nephrotic proteinuria (60.1% vs. 23.7%; P<0.001).1
NOS lesions were the most common type in both groups but were more frequent in nephrotic patients (80.3% vs. 64.0%; P<0.001).1
Key takeaway
At the time of biopsy, Black patients were more likely to be younger and present with advanced CKD and more severe histological disease compared with White patients.1
Timelier identification of FSGS could increase the opportunity for therapeutic intervention, especially for high-risk patients.1
Related Content
Differentiating Primary and Secondary FSGS Using Non‑Invasive Urine Biomarkers
Clinical Kidney Journal – 2023
Footnotes
This study was funded by Travere Therapeutics, Inc. Please see the publication for the full list of disclosures.
CKD, chronic kidney disease; CI, confidence interval; eGFR, estimated glomerular filtration rate; FSGS, focal segmental glomerulosclerosis; GS, glomerulosclerosis; IFTA, interstitial fibrosis and tubular atrophy; NOS, not otherwise specified; OR, odds ratio.
- Tuttle KR et al. Kidney Med. 2024;6(2):100748.
- Reidy K and Kaskel FJ. Pediatr Nephrol. 2007;22(3):350-354.
- D’Agati VD et al. Clin J Am Soc Nephrol. 2013;8(3):399.
- Sprangers B et al. Biomed Res Int. 2016;2016:4632768.
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