Prognosis of IgA Nephropathy with No Proteinuria on Routine Urinalysis

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/ ≥ 1.73m 2 ), 2 (GFR 60-89 ml/min/1.73m 2 ), 3 (GFR 30-59 ml/min/1.73m 2 ) 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.