Using corticosteroids (CS) to treat patients with IgA nephropathy decreases the risk of disease progression regardless of initial estimated glomerular filtration rate (eGFR), new research suggests.

Current guidelines suggest CS treatment in patients with IgA nephropathy (IgAN) when eGFR is higher than 50 mL/min/1.73 m² and proteinuria is persistently 1 g/day or more despite 3–6 months of supportive care. Whether the benefits of this treatment extend to patients with an eGFR of 50 mL/min/1.73 m² or below, other levels of proteinuria, or different renal pathologic lesions remains unknown, according to researchers.

In a retrospective study, Rosanna Coppo, MD, of Turin Hospital in Turin, Italy, and colleagues analyzed data from 1,147 patients with IgAN from the European Validation Study of the Oxford Classification of IgAN (VALIGA) cohort. Physicians prescribed immunosuppression for 46% of the patients. Of these, 98% received CS.

Using a propensity score, the investigators matched 184 patients who received CS and renin-angiotensin system blockade (RASB) to 184 patients with a similar risk profile of progression who received only RASB. At the time of biopsy, 115 of the 368 patients had an eGFR of 50 mL/min/1.73 m² or less (54 who received RASB alone and 61 who received CS and RASB) and 253 had an eGFR above 50 mL/min/1.73 m2 (130 who received RASB alone and 123 who received CS and RASB).

In the propensity score-matched subgroup, CS treatment decreased proteinuria and the rate of renal function decline and increased renal survival, Dr. Coppo's group reported online ahead of print in the Journal of the American Society of Nephrology. During the entire follow-up, mean proteinuria values declined by 0.8 g/day in the CS-RASB group compared with a decline of 3.2 g/day in the RASB group. Renal function declined by 1.0 mL/min/1.73 m² per year in the CS-RASB group versus a decline of 3.2 mL/min/1.73 m² per year in the RASB group. 

A total of 84 patients in the CS group experienced a reduction in proteinuria to less than 1 g/day compared with 54 patients in the RASB group. A reduction in proteinuria to ESRD developed in 7 patients in the CS-RASB group compared with 20 in the RASB group. All of these between-group differences were statistically significant.

These benefits extended to patients with an eGFR of 50 mL/min/1.73 m² or less, with the benefits increasing proportionately with the level of proteinuria. Among the patients in this subgroup, eGFR declined by 0.3 mL/min/1.73 m²per year in the CS-RASB recipients compared with a decline of 4.8 mL/min/1.73 m² per year in the RASB group. In addition, 74% in the CS group reached a proteinuria level below 1 g/day compared with 37% of the RASB group.

“Although this retrospective analysis cannot provide an explicit recommendation for the use of CS within this group until randomized trials confirm our findings, clinicians should consider this option, especially in those with an elevated proteinuria despite optimal conservative therapy,” the authors concluded.

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