Optimal proteinuria target for renoprotection in patients with IgA nephropathy

Proteinuria is a target for renoprotection in kidney diseases. However, optimal level of proteinuria reduction in IgA nephropathy (IgAN) is unknown. We conducted a retrospective observational study in 500 patients with biopsy-proven IgAN. Time-averaged proteinuria (TA-P) was calculated as the mean of every 6 month period of measurements of spot urine protein-to-creatinine ratio. The study endpoints were a 50% decline in estimated glomerular filtration rate (eGFR), onset of end-stage renal disease (ESRD), and slope of eGFR. During a median follow-up duration of 65 (12-154) months, a 50% decline in eGFR occurred in 1 (0.8%) patient with TA-P of