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Kidney Week

Abstract: PO0448

Clinical Significance and Related Factors of GFR Slope in a Large Multicenter Observational Study in Japan

Session Information

Category: CKD (Non-Dialysis)

  • 2101 CKD (Non-Dialysis): Epidemiology, Risk Factors, and Prevention

Authors

  • Kamijo, Yuji, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
  • Hashimoto, Koji, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
  • Yamada, Yosuke, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
  • Harada, Makoto, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
  • Aida, Masatsugu, Nagano Kidney Evaluation Association, Matsumoto, Japan
  • Yamauchi, Shitotomo, Nagano Kidney Evaluation Association, Matsumoto, Japan

Group or Team Name

  • NKEA study group
Background

Recently, GFR slope has attracted attention as an important surrogate marker for the prognosis of CKD, with a reduction in slope of GFR decline by 0.75 mL/min/1.73 m2 per year reportedly having clinical significance. This investigation addresses the clinical significance of GFR slope and its related factors on Japanese CKD patients.

Methods

CKD patients in 15 general hospitals between January and March 2014 were surveyed using medical records. The selection criteria were age ≥20 years, eGFR <60 mL/min/1.73 m2, and receiving medical treatment for CKD. Baseline patient characteristics, eGFR changes, and hard endpoints (death or ESKD requiring RRT) were analysed. We calculated GFR slope using GFR data of 2 years by 2 calculation methods, the linear mixed model and least squares linear regression, and examined the relationship of GFR slope with the hazard ratio (HR) of the endpoints. The factors related to GFR slope were also assessed by multiple regression analysis.

Results

Among a total of 11233 patients, we analyzed the data of 7490 CKD G3 and G4 patients (60% male, mean age: 71 years, CKD G3a: 55%, G3b: 30%, G4: 15%, mean eGFR: 44 mL/min/1.73 m2, urine protein positive: 51%, diabetes mellitus: 49%, use of RAS-I: 57%). The mean observation period was 1040 days. Hard endpoints after the GFR slope measurement period occurred in 301 subjects. The GFR slope of the cohort was -0.948 mL/min/1.73 m2 per year (95% confidence interval [CI] -1.016, -0.880) in the linear mixed model and -0.982 mL/min/1.73 m2 per year (95% CI -1.075, -0.889) according to least squares linear regression. Both calculated GFR slopes were significantly related to the HR of the composite hard endpoints. HR decreased by 0.85 (linear mixed model) and 0.9 (least squares linear regression) times in case of a reduction in slope of GFR decline by 0.75 mL/min/1.73 m2 per year. Multiple regression analysis revealed strongly significant associations for GFR slope with urine protein and CKD stage and undetectable relationships for GFR slope with diabetes and age.

Conclusion

This study demonstrated the clinical significance of GFR slope as a surrogate marker for renal prognosis in Japanese CKD patients. In order to reduce slope of eGFR decline, active intervention for proteinuria before the progression to an advanced CKD stage appears to be effective.