(A) Effect of The Refitted CKD-EPI Race-Free Formula to Estimate Glomerular Filtration Rate on The Chronic Kidney Disease Prevalence and Mortality in The Danish Population

Sunday, August 28, 2022

8:00 AM – 6:00 PM CEST

Location: Hall E South

Publication Number: 1000

Presenting Author(s)

Uffe Heide-Jørgensen
– Aarhus N, Midtjylland, Denmark

Co-Author(s)

Søren Vestergaard, MD
– Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus N, Midtjylland, Denmark
Henrik Birn
– Department of Clinical Medicine, Aarhus University, Denmark, Denmark
Christian Christiansen, MD,PhD
– Professor, Consultant, Department of Clinical Epidemiology, Aarhus University and Aarhus University Hospital, Aarhus, Denmark, Aarhus N, Midtjylland, Denmark

Background: In clinical practice, kidney function (i.e., glomerular filtration rate, GFR) is often estimated (eGFR) using the CKD-EPI formula. The formula is derived from large studies comparing measured GFR with a number of clinical characteristics of which serum creatinine, sex, age, and race (black vs. non-black) have proven to be significant. The correction for race implies that people of black race will have a greater eGFR than non-black people with similar serum-creatinine, which may affect decisions on medical intervention, referrals, and drug dosing. To improve health equity a new refitted CKD-EPI formula, that does not include race has been proposed.

Objectives: To estimate and compare the prevalence of chronic kidney disease (CKD) in the predominantly non-black Danish population using the original and refitted CKD-EPI formula. To describe the characteristics and 1-year mortality in the resulting CKD populations.

Methods: Using nationwide Danish population-based registries, we identified all adults in Denmark on 1 January 2019; extracted all their outpatient creatinine tests in 2016-2018 from biochemical databases; computed eGFR based on the original and refitted formulas assuming non-black race; and identified individuals with CKD. CKD was defined as having eGFR < 60 ml/min/1.73m2 measured twice at least 90 days apart. We computed the prevalence of CKD using the original and refitted formulas and described the distribution of CKD stage, age, sex, and the prevalence of diabetes, liver disease, chronic pulmonary disease, connective tissue disease, heart failure, thromboembolic disease, and cancer within these populations. We used the Kaplan-Meier method to estimate 1-year mortality among persons with CKD, overall and by CKD stage.

Results: Among 4,768,234 adults, we identified 261,625 persons with CKD (prevalence: 5.5%) using the original formula, but only 198,367 (prevalence: 4.2%) using the refitted formula. The distribution of CKD stage, age, and sex were similar within the two CKD-populations. The CKD-population identified by the refitted formula had slightly higher comorbidity burden; most noticeably diabetes (27% vs 24%). The 1-year mortality was higher using the refitted formula (8.9%) than using the original (7.9%). The difference in mortality was most predominant for CKD stage 3a and decreased with increasing stage both in absolute and relative terms.

Conclusions: Compared with the original CKD-EPI formula, the refitted formula reduced CKD prevalence by 24% and resulted in a population with a slightly increased comorbidity burden and mortality.