#567 Early application of treatment to patients with IgA nephropathy who were supposed to have steroid regimen predicts good renal outcome

Abstract

Abstract Background and Aims Progressive deterioration of proteinuria and glomerular filtration rate (GFR) is notified in 20-30% of patients with IgA nephropathy during 20-30 years follow-up period. Popular traditional approach for patients with rapid deterioration of renal function is the immunosuppressive treatment with steroid, which efficacy is still remained in debate. We searched the factors related to renal outcomes among patients presumed to need steroid treatment. Method Among 472 adult patients with IgA nephropathy diagnosed by renal biopsy during 2003-2017 in a tertiary hospital, we selected 86 patients with initiation of steroid treatment for more than 1 months and with dose of more than 1000 mg of prednisolone after renal biopsy. We excluded patients with steroid treatment started one month or more before renal biopsy. The renal outcome was defined as decrease of GFR more than 50% from GFR at renal biopsy, decrease of GFR to less than 15 ml/min/1.73 m2, or a status to need renal replacement therapy during follow-up period after renal biopsy. Results At admission for renal biopsy, estimated GFR by CKD-EPI 2009 equation was 68.5 ± 33.3 ml/min/1.73 m2 and urine protein to creatinine ratio (UPCR) was 2.81 ± 2.23 g/g creatinine (no missing data). The renin-angiotensin-aldosterone inhibitor was used in 80 patients (93.0 %) after renal biopsy. Steroid was started at 8.4 ± 23.1 months after renal biopsy. Majority of patients (63 patients) had been prescribed steroid medication within 2 months after renal biopsy. Total dose of steroid was 13.5 ± 13.1 g. The results of eGFR and UPCR before starting steroid medication were 63.7 ± 31.2 ml/min/1.73 m2 and 2.82 ± 2.01 g/g creatinine, respectively. During 63.6 ± 48.8 months of follow-up period after renal biopsy, there were 39 patients (45.3 %) developed the renal outcome. Factors related to development of the renal outcome searched by correlation coefficient were eGFR and UPCR at renal biopsy, medications of anti-diabetic agent, anti-hypertensive agent, immunosuppressive agent other than steroid, dose of steroid, or vitamin D3 agent after renal biopsy, pathologic findings of segmental sclerosis, interstitial inflammation, and tubular atrophy on light microscopic examination, deposition of C3 and IgA on immunofluorescent staining, and Oxford classification of T, period of starting steroid treatment after renal biopsy, and eGFR before starting steroid medication. With Cox's hazard proportional model, the independent factors to predict the renal outcome were eGFR before steroid treatment or eGFR at renal biopsy, immunosuppressive medication other than steroid, pathologic finding of C3 deposition, and period of starting steroid treatment. Hazard ratio to estimate the renal outcome (HR) was 1.025 (95% CI: 1.010-1.039, p = 0.001) for one-month delay of starting steroid medication after renal biopsy. The HR for the renal outcome in patients started steroid medication at 2 months after renal biopsy was 2.353 (95% CI: 1.140-4.856, P = 0.021) compared to patients started steroid within 2 months after renal biopsy. Conclusion For the patients supposed to have indications for steroid treatment at renal biopsy, early initiation of steroid treatment would indicate better renal outcome.