Prognosis of IgA Nephropathy with No Proteinuria on Routine Urinalysis

Korean Journal of Nephrology 2010;29(6):702-707.

Jong Bin Kim, M.D., Jung Min Kim, M.D., Young Ki Son, M.D., Su Mi Lee, M.D., Hye In Kim, M.D., Won Suk An, M.D., Seong Eun Kim, M.D. and Ki Hyun Kim, M.D.

Department of Internal Medicine, Dong-A University College of Medicine, Busan, Korea

원저 : 일반 요검사상 단백뇨가 없는 IgA 신병증의 예후

김종빈, 김정민, 손영기, 이수미, 김혜인, 안원석, 김성은, 김기현

동아대학교의료원 내과학교실

Abstract

Purpose: In patients with IgA nephropathy, more than 1 g/day of proteinuria is a risk factor to develop end-stage renal failure. Uncommonly, patients with IgA nephropathy exhibit negative proteinuria on routine dipstick test during follow-up examination, spontaneously or after use of ACEI or ARB. We evaluated whether no proteinuric patients have good prognosis or not. Methods: 41 patients who had no proteinuria on routine urinalysis for more than 6 months, were classified into spontaneous remission group (25 cases, SR) without any treatment and drug-induced remission group (16 cases, DR) with treatment of ACEI/ARB or both, were analyzed for clinical findings and renal function, retrospectively. We examined spot urine protein/creatinine ratio (Up/c) to evaluate exact amount of proteinuria and GFR was estimated by MDRD equation. Results: Twenty eight percent of cases in SR and 50 percent in DR showed spot Up/c 0.3-1 g/g. After follow-up of 58±41 (9-192) months in SR and 79±56 (35-192) months in DR, the stages of CKD shifted to advanced levels as follows; in SR group, 11, 10, 4 patients in stage 1 (GFR≥90 ml/min/1.73m2), 2 (GFR 60-89 ml/min/1.73m2), 3 (GFR 30-59 ml/min/1.73m2) to 7, 13, 5 patients, respectively; in DR, 7, 8, 1 patients in stage 1, 2, 3 to 3, 8, 5 patients, respectively. There was a tendency of slow decreasing GFR in both groups but no case progressed to CKD stage 4 and 5. Conclusion: Of IgA nephropathy patients with no proteinuria on routine urinalysis, 30-50% of patients have proteinuria 0.3-1.0 g/g on spot Up/c and there was also a risk of progression.

Key Words: IgA nephropathy, Remission, Proteinuria, Prognosis