Targeted-release budesonide versus systemic corticosteroids in IgA nephropathy: a real-world comparative study

Background: Targeted-release budesonide (Nefecon) has demonstrated efficacy in randomized trials for IgA nephropathy (IgAN), yet direct comparative real-world evidence against systemic corticosteroids is scarce, limiting clinical decision-making. Methods: We conducted a longitudinal real-world study of adult patients with biopsy-proven IgAN treated with either Nefecon or systemic corticosteroids. Renal outcomes, including estimated glomerular filtration rate (eGFR), urinary albumin-to-creatinine ratio (UACR), 24-hour urinary protein excretion (24hUP), and urinary red blood cell count (URBC), were assessed at baseline and at 3, 6, and 9 months. Longitudinal associations were evaluated using linear mixed-effects models adjusted for age, sex, systolic and diastolic blood pressure, with multiple imputation for missing data. Results: A total of 82 patients were included (Nefecon, n=32; systemic corticosteroids, n=50). Both treatments were associated with significant reductions in proteinuria-related outcomes over time. Compared with systemic corticosteroids, Nefecon showed a trend toward greater early reduction in UACR at 3 months after expanded adjustment and an adjusted exploratory short-term favorable difference in eGFR at 6 months. However, this eGFR difference was not sustained at 9 months, and the primary outcome (24hUP) showed no significant between-group difference at any time point.Severe infections and steroid-related adverse events were numerically less frequent in the Nefecon group. Conclusions: In routine clinical practice, Nefecon showed antiproteinuric efficacy comparable to systemic corticosteroids, with no significant difference in the primary outcome (24hUP) between groups. An exploratory short-term favorable eGFR signal was observed at 6 months, but this was not sustained at 9 months and should not be interpreted as evidence of sustained renal protection. Severe infections and steroid-related adverse events were numerically less frequent in the Nefecon group, but limited event counts warrant cautious interpretation. Longer follow-up is required to determine whether these exploratory findings are clinically meaningful.