Abstract
Current guidelines suggest treatment with corticosteroids (CS) in IgA nephropathy (IgAN) when proteinuria is persistently >1 g/d despite 3-6 months of supportive care and when eGFR is >50 ml/min per 1.73 m2. Whether the benefits of this treatment extend to patients with an eGFR50 ml/min per 1.73 m2, other levels of proteinuria, or different renal pathologic lesions remains unknown.
We retrospectively studied 1147 patients with IgAN from the European Validation Study of the Oxford Classification of IgAN (VALIGA) cohort classified according to the Oxford-MEST classification and medication used, with details of duration but not dosing. Overall, 46% of patients received immunosuppression, of which 98% received CS.
Treated individuals presented with greater clinical and pathologic risk factors of progression. They also received more antihypertensive medication, and a greater proportion received renin angiotensin system blockade (RASB) compared with individuals without immunosuppressive therapy.
Immunosuppression was associated with a significant reduction in proteinuria, a slower rate of renal function decline, and greater renal survival. Using a propensity score, we matched 184 subjects who received CS and RASB to 184 patients with a similar risk profile of progression who received only RASB.
Within this group, CS reduced proteinuria and the rate of renal function decline and increased renal survival. These benefits extended to those with an eGFR50 ml/min per 1.73 m(2), and the benefits increased proportionally with the level of proteinuria.
Thus, CS reduced the risk of progression regardless of initial eGFR and in direct proportion to the extent of proteinuria in this cohort.