Long-term prognosis of clinically early IgA nephropathy is not always favorable

Abstract

Background: The long-term prognosis of clinically early IgA nephropathy (IgAN) patients remains to be clarified. We investigated the long-term outcomes of IgAN patients with an apparently benign presentation and evaluated prognostic factors for renal survival.

Methods: We included patients with biopsy-proven IgAN who had estimated glomerular filtration rates (eGFR) ≥ 60 mL/min/1.73 m2, normal blood pressure, and proteinuria <0.5 g/day at the time of biopsy. The primary outcome was progression to end-stage renal disease (ESRD). The secondary outcome was a 50% increase in serum creatinine level or an increase in proteinuria to >1 g/day.

Results: The analysis included 153 patients who met the inclusion criteria. At diagnosis, their median systolic blood pressure was 120 (110-130) mmHg, eGFR was 85.9 (74.9-100.1) mL/min/1.73 m2, and proteinuria was 0.25 (0.13-0.38) g/day. Of these, 4 patients died and 6 reached ESRD. The 30-year renal survival rate was 85.5%. Three patients had increased serum creatinine levels and 11 developed proteinuria. Remission was observed in 35 (22.9%) patients. A moderate or severe degree of interstitial fibrosis (adjusted odd ratio [OR] 5.93, 95% confidence interval [CI] 1.44-24.45, P=0.014) and hypoalbuminemia (adjusted OR 6.18, 95% CI 1.20-31.79, P=0.029) were independent predictors of the secondary outcome.

Conclusions: This study showed that the prognosis of early IgAN was not always favorable, even resulting in progression to ESRD in some cases. Hypoalbuminemia and interstitial fibrosis should also be considered important prognostic factors in clinically early IgAN patients.

Figure 1

Participation flow diagram.

Figure 2

Cumulative renal and patient survival after kidney biopsy in early IgAN patients. The primary endpoint is free of death or end stage renal disease. The number of patients remaining at 60, 120, 180, 240, 300 and 360 months of follow–up are shown at the bottom.