Clinical Response to Intestine-targeted Steroid Therapy in Biopsy-proven Immunoglobulin A Nephropathy

Abstract

Primary immunoglobulin A (IgA) nephropathy is associated with a dysfunctional mucosal immune system, leading to renal deposition of IgA and injury. Fifty patients with biopsy-proven IgA nephropathy were included. All patients were initiated on renin-angiotensin-aldosterone system (RAAS) inhibitors, polyunsaturated fatty acids, and a controlled release formulation (CRF) of budesonide. All drugs were started together, as isolated RAAS inhibitors will not prevent the immunological damage caused by the ongoing deposition of IgA. Depending on the histology (mesangial hypercellularity, endocapillary proliferation, segmental glomerulosclerosis, tubular atrophy/interstitial fibrosis, and crescents score), the patients received 9 mg or 12 mg of budesonide. All patients were followed up every 4 weeks to monitor renal function, 24-h urinary protein, and adverse effects. Our primary outcome was a mean change in the estimated glomerular filtration rate (eGFR) and 24-h urinary protein from the baseline to the end of 6 months. The percentage of decline in mean 24-h protein at 6 months from the baseline was 33%. The mean decrease in serum creatinine from the baseline was 0.73 mg/dL. The mean gain in eGFR from the baseline was an increase of 9 mL/min/1.73 m2. Of 50 patients, 11 (22%) achieved complete remission, 20 (40%) achieved partial remission, and 16 (32%) were non-responders. Three patients (6%) were lost to follow-up. The early initiation of CRF budesonide with optimized supportive care led to reductions in proteinuria and improvements in eGFR at 6 months in patients with IgA nephropathy. Early lesions with minimal chronicity showed an excellent response to budesonide.