Abstract: FR-OR020

Comparison of Estimated versus Measured GFR Decline in the Association with ESRD and Mortality

Session Information

Category: Chronic Kidney Disease (Non-Dialysis)

  • 302 CKD: Estimating Equations, Incidence, Prevalence, Special Populations

Authors

  • van Rijn, Marieke, Radboud Univ Medical Centre, The Netherlands; Inserm U1018, France, Nijmegen, Netherlands
  • Leffondre, Karen, University of Bordeaux, Bordeaux, France
  • Metzger, Marie, CESP U1018, INSERM, Villejuif, France
  • Flamant, Martin, APHP, Paris, France
  • Haymann, Jean-philippe, UPMC, INSERM UMRS 702, AH-HP, Paris, France
  • Stengel, Benedicte, Inserm – DRPA11, Le Kremlin-Bicêtre Cedex, France
  • van den Brand, Jan A.J.G., Radboud University Nijmegen Medical Center, Nijmegen, Netherlands

Group or Team Name

  • On behalf of NephroTest study group
Background

There is growing interest for GFR decline as an alternative endpoint for end-stage renal disease (ESRD), but whether using estimated GFR (eGFR) instead of measured GFR (mGFR) is appropriate has not been evaluated. We compared the association of eGFR and mGFR decline with risk for ESRD and mortality in patients with CKD.

Methods

We included 1734 adult patients with CKD stage 1 to 4 who had a total of 4790 simultaneous eGFR and mGFR measurements, over a median 3.3-year follow-up (IQR: 2.0-5.4). mGFR was measured with 51Cr-EDTA renal clearance and CKD-EPI eGFR was based on IDMS-traceable creatinine. We used shared parameter joint models to estimate the association between current value and slope of eGFR or mGFR and ESRD or death, adjusted for baseline age, gender, and albumin to creatinine ratio (ACR).

Results

Patients (mean age 59±15 yrs, 31% women) had a median of 2.0 (IQR 1.0-4.0) visits, a mean mGFR of 43.5 mL/min/1.73m2 , and a median ACR of 8.0 mg/mmol (IQR: 1.5-46.2). eGFR and mGFR decline was comparable, 1.87 (2.02-1.73) versus 1.88 (2.04-1.73) mL/min/1.73m2/year, respectively. HRs for death were similar for both current value and slope of mGFR or eGFR. In contrast, HRs for ESRD were lower when using current value and slope of mGFR than eGFR.

Conclusion

This study shows that the association of GFR slope with mortality is similar whether using eGFR or mGFR, but not that with ESRD. The hazard ratio of ESRD is lower with mGFR than eGFR. Therefore, mGFR decline may be considered as an alternative endpoint for ESRD rather than eGFR in clinical trials.

 HR for death (95% CI)HR for ESRD (95%CI)
 mGFRCKD-EPI eGFRmGFRCKD-EPI eGFR
Current GFR (ml/min/1.73m2)0,98 (0,97 – 0,99)0,98 (0,97 – 0,99)0,84 (0,81- 0,87)0,86 (0,83 – 0,88)
Current GFR slope (ml/min/1.73m2 per year)0,89 (0,78 – 1,02)0,89 (0,79 – 0,99)0,80 (0,66 – 0,97)0,85 (0,73 – 0,99)
2log ACR (mg/mmol)1,04 (0,99 – 1,09)1,05 (1,00 – 1,09)1,23 (1,14 – 1,33)1,26 (1,17 – 1,36)