Serum immunoglobulin A/C3 ratio predicts progression of immunoglobulin A nephropathy

Nephrology (Carlton). 2013 Feb;18(2):125-31. doi: 10.1111/nep.12010.

Abstract

Aim: The serum immunoglobulin A (IgA)/C3 ratio has been shown to be a good predictor of histological lesions and prognosis for patients with IgA nephropathy (IgAN) in Japanese. But its validity in the Chinese population is unclear. We sought to explore the long-term outcomes of IgAN, its clinical and histopathological predictors in Chinese patients. In particular, the role of serum IgA/C3 ratio in the course of IgAN was addressed.

Methods: A total of 217 biopsy-diagnosed IgAN patients were recruited into this prospective cohort with a mean follow-up of 36 months (25-75th percentile, 27-48). Sociodemographics, serum IgA/C3 level, other clinical examinations and Lee's histological grade were measured. The patients with a decline of estimated glomerular filtration rate (eGFR) > 50% or developing end-stage renal disease (ESRD) were defined as progression.

Results: A total of 21 patients was found to progress (9.7%). In multivariate analysis, renal end point of IgAN was significantly predicted by proteinuria ≥1 g/day (relative risk (RR) = 2.65, 95% confidence interval (CI) 1.01-7.68), hypertension (RR = 3.15, 95% CI 1.07-9.29), higher Lee's histological grade (RR = 4.67, 95% CI 1.43-15.25) and serum IgA/C3 ratio ≥ 3.32 (RR = 4.31, 95% CI 1.33-13.96).

Conclusion: A proportion of patients with IgAN developed end stage renal disease in a Chinese group. In addition to some traditional risk factors, we also confirmed that IgA/C3 ratio is a useful predictor of poor outcomes of IgAN in Chinese patients.

MeSH terms

  • Adult
  • Asian Continental Ancestry Group
  • Biomarkers / blood
  • Biopsy
  • Chi-Square Distribution
  • China / epidemiology
  • Complement C3 / analysis*
  • Disease Progression
  • Female
  • Glomerular Filtration Rate
  • Glomerulonephritis, IGA / blood
  • Glomerulonephritis, IGA / ethnology
  • Glomerulonephritis, IGA / immunology*
  • Glomerulonephritis, IGA / pathology
  • Glomerulonephritis, IGA / physiopathology
  • Humans
  • Immunoglobulin A / blood*
  • Kaplan-Meier Estimate
  • Kidney / pathology
  • Kidney / physiopathology
  • Kidney Failure, Chronic / ethnology
  • Kidney Failure, Chronic / immunology
  • Male
  • Multivariate Analysis
  • Predictive Value of Tests
  • Prognosis
  • Proportional Hazards Models
  • Prospective Studies
  • Proteinuria / ethnology
  • Proteinuria / immunology
  • Risk Factors
  • Time Factors
  • Young Adult

Substances

  • Biomarkers
  • Complement C3
  • Immunoglobulin A