Kidney Week

Abstract: TH-PO780

Validation of the Novel "Race Free" CKD-EPI Equation in Persons Aged 70 and Older: The Berlin Initiative Study

Session Information

• Voices, Choices, and Outcomes of Older Adults with CKD
  November 03, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
  Abstract Time: 10:00 AM - 12:00 PM

Category: Geriatric Nephrology

• 1200 Geriatric Nephrology

Authors

• Ebert, Natalie, Charite Universitatsmedizin Berlin, Berlin, Berlin, Germany

Natalie Ebert,

• Pottel, Hans, KULeuven University, Kortrijk, Belgium

Hans Pottel,

• Delanaye, Pierre, Sart Tilman University, Liège, Belgium

Pierre Delanaye,

• van der Giet, Markus, Charite Universitatsmedizin Berlin, Berlin, Berlin, Germany

Markus van der Giet,

• Kuhlmann, Martin K., Vivantes Klinikum im Friedrichshain, Berlin, Berlin, Germany

Martin K. Kuhlmann,

• Schaeffner, Elke, Charite Universitatsmedizin Berlin, Berlin, Berlin, Germany

Elke Schaeffner,

Background

The creatinine-based CKD-EPI (ASR) equation from 2009 (ASR: age, sex, and race) has been replaced by the CKD-EPI (AS) equation using the same mathematical form without the race variable because the former has been considered a source of discrimination. NKF recently recommended using the "race free“ CKD-EPI (AS) equation for patients in the US. It is unclear whether this is favorable for older patients. Our study compares the performance of CKD-EPI (AS), CKD-EPI (ASR), and the European Kidney Function Consortium (EKFC) equation.

Methods

We analyzed data from 570 participants of the "Berlin Initiative Study“ (BIS), a community-dwelling cohort of white older adults. We measured GFR (mGFR) with iohexol plasma clearance as gold standard. We calculated bias as estimated GFR (eGFR) minus mGFR, precision (interquartile range, IQR), and accuracy (P30: percentage of eGFR values within +/- 30% mGFR). CKD-EPI (ASR), CKD-EPI (AS) and EKFC equations were validated using mGFR.

Results

Mean age was 78.5 yrs, 57% were male, and mean mGFR was 60.3 ml/min/1.73m². Mean Bias for CKD-EPI (AS) was highest with 13.0 compared to 8.4 and 1.6 ml/min/1.73m² for CKD-EPI (ASR) and EKFC (Tbl. 1). P30 value was lowest for CKD-EPI (AS) (67%) compared to CKD-EPI (ASR, 81%) and EKFC (92%). Stratified by age (≥80 yrs) and mGFR (mGFR <60), we found even worse P30 results for CKD-EPI (AS) with 58% and 52% (Fig. 1).

Conclusion

In the US, the novel "race-free“ CKD-EPI (AS) equation is recommended for diagnosing CKD. Our results suggest that CKD-EPI (AS) leads to a considerable systematic overestimation and worse prediction of eGFR in older patients. In pts. with GFR <60, P30 was even worse with only 52%, enhancing the risk of drug overdosing and delayed CKD diagnosis.

Funding

• Private Foundation Support