IgA nephropathy is the most common primary glomerulonephritis, yet it had no disease-specific therapy until 2021 — and 30–40% of patients still progress to kidney failure.
IgA nephropathy is a primary glomerular disease driven by circulating galactose-deficient IgA1 (Gd-IgA1): autoantibodies form immune complexes that deposit in the glomerular mesangium, activate complement and drive progressive glomerular injury (PMID 21949093). It is the most common biopsy-proven primary glomerulonephritis. In a large racially and ethnically diverse US population, adult primary IgAN incidence was roughly 1.29–2.2 new cases per 100,000 per year, with the highest rates in patients of Asian ancestry and the lowest in Black patients (PMID 39496243). Because a confirmed diagnosis requires a kidney biopsy, milder disease managed as chronic kidney disease without biopsy is not formally captured — so the diagnosed pool understates true prevalence.
The disease is slow but rarely benign: 30–40% of patients progress to end-stage kidney disease over 20–30 years (PMID 27189177), and the RaDaR registry reports a median kidney survival of roughly 11 years from diagnosis for patients under nephrology follow-up (PMID 37055195). Proteinuria and eGFR trajectory are the validated levers of long-term outcome, and GFR slope is now an accepted surrogate for progression in kidney-disease trials (PMID 31292197). That evidence base underwrote a rapid therapeutic shift: from renin-angiotensin system (RAS) blockade plus an SGLT2 inhibitor as the supportive-care backbone to five FDA-approved disease-modifying agents across four mechanisms between 2021 and 2026.
IgA nephropathy — US epidemiology, diagnosis and progression at a glance
| Dimension | Measure | Detail | Source |
|---|---|---|---|
| Incidence (US) | ~1.29–2.2 / 100,000/yr | Adult primary IgAN in a racially/ethnically diverse cohort; highest in Asian, lowest in Black patients | Am J Nephrol (PMID 39496243) |
| Disease driver | Galactose-deficient IgA1 | Gd-IgA1 immune complexes deposit in the mesangium, activate complement, drive glomerular injury (multi-hit) | J Am Soc Nephrol (PMID 21949093) |
| Diagnosis | Kidney biopsy + Oxford MEST-C | Biopsy required to confirm primary IgAN; MEST-C histologic score carries prognostic weight | N Engl J Med review (PMID 23782179) |
| Risk stratification | Proteinuria (UPCR) + eGFR | Higher proteinuria and lower eGFR predict faster progression; GFR slope is an accepted trial surrogate | J Am Soc Nephrol (PMID 31292197) |
| Progression to ESKD | 30–40% over 20–30 yr | Lifetime risk of kidney failure without disease modification | Nat Rev Dis Primers (PMID 27189177) |
| Long-term outcome | ~11 yr median kidney survival | RaDaR registry, patients under nephrology follow-up | CJASN (PMID 37055195) |
Sources: American Journal of Nephrology diverse-population incidence study (PMID 39496243); Nature Reviews Disease Primers IgAN (PMID 27189177); RaDaR registry, CJASN (PMID 37055195); NEJM IgAN clinical review (PMID 23782179); JASN Gd-IgA1 pathophysiology (PMID 21949093); JASN GFR-slope surrogate meta-analysis (PMID 31292197); KDIGO 2025 IgAN/IgAV guideline.
What this assessment answers
Every section answers a named commercial question your team is asking, scoped to your asset.
Delivers
- • US incidence and racial/ethnic variation from a diverse-population cohort • The biopsy requirement as a diagnostic gate and its underdiagnosis implication • Proteinuria (UPCR) and eGFR risk stratification of the diagnosed pool • The progression-risk segment that anchors disease-modifying therapy eligibility
Delivers
- • Kidney-biopsy diagnostic standard and referral pathway • Oxford MEST-C histologic scoring and its prognostic weight • Gd-IgA1 as an emerging activity and treatment-response biomarker • Where proteinuria and eGFR thresholds sit in risk classification
Delivers
- • The 2021→2026 approval wave across endothelin, complement, APRIL and gut-directed mechanisms • KDIGO 2025 treatment pathway: RAS blockade + SGLT2i backbone plus disease-specific add-on • Where each mechanism layers onto optimized supportive care • Proteinuria vs eGFR as the evidence standard behind accelerated approvals
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Commission This AssessmentWhat's inside
- How galactose-deficient IgA1 autoantibodies form immune complexes that deposit in the glomerular mesangium and activate complement
- Why IgA nephropathy is classified as the most common biopsy-proven primary glomerulonephritis
- Why incidence in the same diverse US cohort is highest among patients of Asian ancestry and lowest among Black patients
- Why the diagnosed pool understates true prevalence, since a confirmed diagnosis requires a kidney biopsy
- Why a kidney biopsy remains the mandatory diagnostic standard for confirming primary IgA nephropathy
- How the Oxford MEST-C histologic classification score carries independent prognostic weight for disease course
- Why higher proteinuria (UPCR) and lower eGFR predict which patients face the fastest progression to kidney failure
- How GFR slope became an accepted trial surrogate even as 30–40% of patients still progress to ESKD over 20–30 years
- How five FDA-approved agents across four mechanisms (endothelin, complement, APRIL, gut-directed) reshaped treatment between 2021 and 2026
- Why KDIGO 2025 now layers a disease-specific add-on onto an optimized RAS-blockade plus SGLT2 inhibitor backbone
- Why the RaDaR registry puts median kidney survival at roughly 11 years from diagnosis for patients under nephrology follow-up
- How this real-world survival benchmark anchors the case for early disease-modifying intervention
Included with every brief
How AXLRx builds this assessment
Prepared by MoatRx analysts.
Every AXLRx assessment is built from primary sources: peer-reviewed literature, primary regulatory records (FDA Drugs@FDA, ClinicalTrials.gov) and guideline bodies, not secondary summaries or unverified estimates. Epidemiological figures are triangulated across sources and every factual claim is independently verified before inclusion; if a figure cannot be sourced to a live record, it does not ship.
US IgA nephropathy Disease Landscape sources: US incidence and racial/ethnic variation from the American Journal of Nephrology (PMID 39496243); disease mechanism from JASN (PMID 21949093); diagnosis and clinical course from the NEJM IgAN review (PMID 23782179); progression risk from Nature Reviews Disease Primers (PMID 27189177) and the RaDaR registry in CJASN (PMID 37055195); GFR-slope surrogacy from JASN (PMID 31292197); and the KDIGO 2025 IgAN/IgAV guideline for the treatment pathway.
- US incidence and racial/ethnic variation verified against the American Journal of Nephrology diverse-population study (PMID 39496243)
- ESKD progression rate verified against Nature Reviews Disease Primers IgAN (PMID 27189177)
- Long-term kidney survival verified against the RaDaR registry, CJASN (PMID 37055195)
- Gd-IgA1 disease mechanism verified against the JASN pathophysiology review (PMID 21949093)
- GFR-slope surrogacy verified against the JASN GFR-slope meta-analysis (PMID 31292197)
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