Utility of remission criteria for the renal prognosis of IgA nephropathy

Background Novel criteria for the remission of Immunoglobulin A nephropathy (IgAN) based on an opinion survey of Japanese nephrologists and literature review were proposed in 2013. This single-center, longitudinal retrospective cohort study was conducted to validate this criteria. Methods Present study included the IgAN patients diagnosed between 2001 and 2005 in the Juntendo University Hospital. Remission of hematuria was defined as three consecutive dipstick test results of ( -) to ( +/-) or a red blood cell count < 5 in urinary sediment per high-power field during at least 6 months. Remission of proteinuria was defined as three consecutive dipstick results of ( -) to ( +/-) during at least 6 months. We categorized four groups according to the remission status which was assessed 2 years after the renal biopsy. The primary outcome was a 50% increase in the serum creatinine over the baseline. We evaluated the slope of eGFR decline (mL/min/1.73 m(2)/year) and a decrease in the eGFR of 30% from baseline eGFR as the secondary outcome, respectively. Results A total of 74 patients (male: 47.3%, median age: 30 years) were included and were followed for a median of 86.5 months. During the period, forty-one patients achieved neither remission of proteinuria nor hematuria (NR). Twelve patients met the primary study outcome. A survival analysis revealed that the NR had the worst prognosis and the steepest slope of eGFR decline. Conclusion Although further validation in a large cohort is necessary, these novel remission criteria for IgAN patients appear to predict the renal prognosis.