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Abstract: SU-OR36

Grading System Utilizing Total Score of Oxford Classification for Predicting Renal Prognosis in IgA Nephropathy

Session Information

Category: Glomerular Diseases

  • 1203 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

  • Miyabe, Yoei, Department of Nephrology, Tokyo Women’s Medical University, 8-1 Kawada-Cho, Shinjuku-ku, Tokyo, Japan
  • Akiyama, Kenichi, Department of Nephrology, Tokyo Women’s Medical University, 8-1 Kawada-Cho, Shinjuku-ku, Tokyo, Japan
  • Karasawa, Kazunori, Department of Nephrology, Tokyo Women’s Medical University, 8-1 Kawada-Cho, Shinjuku-ku, Tokyo, Japan
  • Nitta, Kosaku, Department of Nephrology, Tokyo Women’s Medical University, 8-1 Kawada-Cho, Shinjuku-ku, Tokyo, Japan
  • Moriyama, Takahito, Department of Nephrology, Tokyo Women’s Medical University, 8-1 Kawada-Cho, Shinjuku-ku, Tokyo, Japan
Background

The Oxford classification of IgA nephropathy (IgAN) can evaluate each MEST-C score individually. However, no research has evaluated the prognosis of IgAN patients using the MEST-C score comprehensively. Therefore, we aimed to analyze the usefulness of a new grading system that utilized the total score of each MEST-C score in predicting renal prognosis.

Methods

A total of 871 IgAN patients were classified into three groups using the new Oxford classification system (O-grade) that utilized the total score of each MEST-C score (O-grade I: 0-1, II: 2-4, and III: 5-7 points) according to the renal survival rate (<10%, 10%-30%, >30%, respectively). The 20-year renal prognosis was analyzed, and the O-grade combined with the Japanese clinical classification (C-grade) was also evaluated.

Results

The clinical findings became significantly severer with increasing O-grades, and the renal survival rate by the Kaplan-Meier method was 78.5%, 74.9%, and 42.2% for O-grades I, II, and III, respectively (P<0.001). The hazard ratios (HRs) for O-grades II and III with reference to O-grade I were 1.7 (95% confidence interval [CI], 1.0-2.9; P=0.036) and 4.7 (95% CI, 2.6-8.4; P<0.001), respectively. In the multivariate analysis, mean blood pressure and renal function, proteinuria, and O-grade (HR, 1.39; 95% CI, 1.02-1.90; P=0.036) were the independent factors predicting the renal prognosis. The renal prognosis in the nine groups classified by the O-grade combined with the C-grade showed HR of 33.7 (P<0.001) in the severest group with reference to the mildest group.

Conclusion

The O-grade classified by the total score of the Oxford classification was associated with renal prognosis, and renal prognosis could be accurately predicted by combining the O-grade with the C-grade. The O-grade allows easier evaluation of the total activity and chronicity of IgAN and prediction of the renal prognosis of this disease.