Optimal proteinuria target for renoprotection in patients with IgA nephropathy

Ki Heon Nam, Jeong Hae Kie, Mi Jung Lee, Tae Ik Chang, Ea Wha Kang, Dong Wook Kim, Beom Jin Lim, Jung Tak Park, Young Eun Kwon, Yung Ly Kim, Kyoung Sook Park, Seong Yeong An, Hyung Jung Oh, Tae Hyun Yoo, Shin Wook Kang, Kyu Hun Choi, Hyeon Joo Jeong, Dae Suk Han, Seung Hyeok Han

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Abstract

Background: Proteinuria is a target for renoprotection in kidney diseases. However, optimal level of proteinuria reduction in IgA nephropathy (IgAN) is unknown. Methods: 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. Results: 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 <0.3 g/g compared to 6 (2.7%) patients with TA-P of 0.3-0.99 g/g (hazard ratio, 2.82; P = 0.35). Risk of reaching a 50% decline in eGFR markedly increased in patients with TA-P of 1.0-2.99 g/g (P = 0.002) and those with TA-P≥3.0 g/g (P<0.001). ESRD did not occur in patients with TA-P<1.0 g/g compared to 26 (20.0%) and 8 (57.1%) patients with TA-P of 1.0-2.99 and ≥3.0 g/g, respectively. Kidney function of these two groups deteriorated faster than those with TA-P<1.0 g/g (P<0.001). However, patients with TA-P of 0.3-0.99 g/g had a greater decline of eGFR than patients with TA-P<0.3 g/g (-0.41±1.68 vs. -0.73±2.82 ml/min/1.73 m2/year, P = 0.03). Conclusion: In this study, patients with TA-P<1.0 g/g show favorable outcomes. However, given the faster eGFR decline in patients with TA-P of 0.3-0.99 g/g than in patients with TA-P<0.3 g/g, the ultimate optimal goal of proteinuria reduction can be lowered in the management of IgAN.

Original languageEnglish
Article numbere101935
JournalPloS one
Volume9
Issue number7
DOIs
Publication statusPublished - 2014 Jul 8

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All Science Journal Classification (ASJC) codes

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)
  • General

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Nam, K. H., Kie, J. H., Lee, M. J., Chang, T. I., Kang, E. W., Kim, D. W., Lim, B. J., Park, J. T., Kwon, Y. E., Kim, Y. L., Park, K. S., An, S. Y., Oh, H. J., Yoo, T. H., Kang, S. W., Choi, K. H., Jeong, H. J., Han, D. S., & Han, S. H. (2014). Optimal proteinuria target for renoprotection in patients with IgA nephropathy. PloS one, 9(7), [e101935]. https://doi.org/10.1371/journal.pone.0101935