Corticosteroids in IgA Nephropathy: A Retrospective Analysis from the VALIGA Study

Area of Science:

• Nephrology
• Immunology
• Internal Medicine

Background:

• Current IgA nephropathy (IgAN) guidelines recommend corticosteroids (CS) for patients with persistent proteinuria (≥1 g/d) and eGFR >50 ml/min/1.73 m².
• The efficacy of CS in IgAN patients with eGFR ≤50 ml/min/1.73 m², varying proteinuria levels, or different MEST-Oxford classifications remains unclear.

Purpose of the Study:

• To evaluate the effectiveness of CS in IgA nephropathy (IgAN) patients, particularly those with reduced kidney function or different proteinuria levels.
• To determine if CS treatment improves proteinuria, renal function decline, and renal survival in IgAN.

Main Methods:

• Retrospective analysis of 1147 IgAN patients from the VALIGA cohort, classified using the Oxford-MEST criteria.
• Propensity score matching was used to compare patients receiving CS plus renin-angiotensin system blockade (RASB) with those receiving RASB alone.

Main Results:

• Immunosuppression, primarily CS, was associated with reduced proteinuria, slower eGFR decline, and improved renal survival.
• CS treatment, combined with RASB, significantly reduced proteinuria, slowed renal function decline, and increased renal survival, irrespective of initial eGFR.
• The benefits of CS were observed in patients with eGFR ≤50 ml/min/1.73 m² and increased proportionally with the level of proteinuria.

Conclusions:

• Corticosteroids (CS) offer significant benefits in IgA nephropathy (IgAN) management, including reduced proteinuria and slower progression, even in patients with impaired kidney function (eGFR ≤50 ml/min/1.73 m²).
• The positive impact of CS treatment is directly proportional to the level of proteinuria, suggesting broader application in IgAN.
• These findings challenge current guidelines and support considering CS for a wider range of IgAN patients based on proteinuria severity and renal function.