Predictors of poor outcomes in steroid therapy for immunoglobulin A nephropathy

Abstract

Steroid therapy appears to be beneficial in patients of immunoglobulin A nephropathy (IgAN), as it causes a reduction in the proteinuria and improves the renal survival. A retrospective review of the 5 year follow-up data of 60 patients with IgAN who were treated with steroids was conducted. Steroid non-responders were defined as patients in whom the primary end-point of a 30% decrease of the estimated glomerular filtration rate from baseline was reached. The patients were divided into two groups, namely, the steroid responder group (n = 47) and the steroid non-responder group (n = 13), and the clinicopathophysiological characteristics were compared between the two groups. Significant decrease of the proteinuria was observed in the responder group over the 5 year follow-up period, whereas no significant change of the urinary protein excretion was observed in the non-responder group during the same period. In regard to the pathological findings, significantly higher ratios of glomerular obsolescence and glomerular tuft adhesion to the Bowman's capsule, and significantly higher severity of interstitial fibrosis at the time of diagnosis in the non-responder group than in the responder group were found. The rates of glomerular obsolescence and glomerular tuft adhesion to the Bowman's capsule, the severity of interstitial fibrosis, serum albumin and urinary protein excretion were identified as independent risk factors influencing the rate of renal function deterioration. To develop effective therapeutic modalities, it is important to have a thorough understanding of the clinicopathophysiological characteristics of IgAN patients showing poor treatment response to steroids (non-responder group in this study).