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Abstract: SA-PO913

Impact of Using the 2021 CKD-EPI Creatinine Equation on Clinical and Surrogate End Points in Trials

Session Information

Category: CKD (Non-Dialysis)

  • 2202 CKD (Non-Dialysis): Clinical‚ Outcomes‚ and Trials

Authors

  • Chaudhari, Juhi, Tufts Medical Center, Boston, Massachusetts, United States
  • Miao, Shiyuan, Tufts Medical Center, Boston, Massachusetts, United States
  • Tighiouart, Hocine, Tufts Clinical and Translational Science Institute, Boston, Massachusetts, United States
  • Inker, Lesley Ann, Tufts Medical Center, Boston, Massachusetts, United States

Group or Team Name

  • Chronic Kidney Disease-Epidemiology Collaboration: Clinical Trials
Background

The new 2021 CKD-EPI creatinine GFR estimating equation that does not include a term for Black race is now recommended to replace the 2009 CKD-EPI creatinine equation in the US. We evaluated the impact of using the 2021 vs 2009 equation on treatment effects of GFR slope and on time-to-confirmed 40% decline in GFR in three past randomized trials.

Methods

In the SPRINT (low vs usual blood pressure control), IDNT (RAS blocker vs calcium channel blocker), and EMPA-REG Outcomes (SGLT2 inhibitor vs placebo) trials, we estimated GFR using the CKD-EPI 2009 and 2021 creatinine equations and computed total GFR slope (randomization to 3 years) as well as chronic slope (excluding the initial 3 months post-randomization) in the whole study as well as in Black and non-Black race groups. We estimated treatment effects on GFR slope as the mean difference in GFR slope between the randomized groups and treatment effects on a composite of time-to-confirmed 40% decline in GFR, GFR<15 mL/min per 1.73 m2 and end-stage kidney disease using Cox proportional hazard regressions.

Results

The mean baseline GFR using the 2009 and 2021 equations are shown in Figure 1, along with the treatment effects on GFR slopes and on the time-to-event outcome. As expected, GFRs were lower for Black individuals using the 2021 equation compared to 2009. The treatment effects on the three outcomes did not meaningfully differ when using the two equations for each study and for Black and non-Black race groups.

Conclusion

Substituting the 2021 CKD-EPI equation for the 2009 equation had minimal numerical impact on the estimated treatment effects on GFR slope and on time-to-confirmed 40% decline in GFR in three past studies as a whole or in the Black race subgroup. It is reasonable to apply the new GFR equation in the design of future trials.

Treatment effects on GFR slope and on time-to-event outcome (composite of confirmed 40% decline in GFR, GFR<15 mL/min per 1.73 m2 and end-stage kidney disease)

Funding

  • Private Foundation Support