Implications of Implementing the 2021 CKD-EPI Equation Without Race on Managing Patients With Kidney Disease in British Columbia, Canada

Abstract

Introduction: We investigated the implications of implementing race-free Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) 2021 equation among real-world patients with chronic kidney disease (CKD) from British Columbia (BC), Canada.

Methods: This study included nondialysis-dependent patients with CKD aged ≥19 years who were registered in the Patient Records and Outcome Management Information System (PROMIS) as of March 31, 2016 (index date) with ≥1 serum creatinine measurement within 1 year before the index date. Patients with a history of kidney transplantation before the index date were excluded. CKD-EPI 2021 versus 2009 equation was the exposure variable. Difference in mean estimated glomerular filtration rate (eGFR) and number (%) of patients reclassified to a different eGFR category were estimated. We used Fine and Gray subdistribution hazard model to investigate the association between change in eGFR category and progression to kidney failure (incident maintenance dialysis or kidney transplantation) within 2 years.

Results: A total of 11,604 patients (median age 73 years, 52% male) were included. Compared to the 2009 equation, eGFR from 2021 equation was on average 2.7 ml/min per 1.73 m² higher. Variation was higher among males. Overall, ∼17% of the study sample were reclassified to a category with higher eGFR by 2021 equation (switchers). The highest proportion (28%) of patients were reclassified from G5 to G4. The risk of progressing to kidney failure was 22% less among switchers compared to nonswitchers; adjusted subdistribution hazard ratio (HR) (95% confidence interval [CI]) is 0.78 (0.65, 0.94).

Conclusion: CKD-EPI 2021 equation appeared to provide higher eGFR compared to 2009 equation. This higher eGFR values appeared to be concordant with subsequent real-world CKD progression outcomes. Higher eGFR from the 2021 equation may have substantial clinical implications in both diagnosis as well as long-term care of patients with CKD.

Keywords: CKD-EPI equation; KFRE; chronic kidney disease; eGFR.

Graphical abstract

Figure 1

Study cohort derivation. CKD, chronic kidney disease.

Figure 2

Distribution of patients in various KDIGO risk categories by eGFR calculated using CKD-EPI 2009 versus 2021 equation. CKD-EPI, Chronic Kidney Disease Epidemiology Collaboration; eGFR, estimated glomerular filtration rate; KDIGO, Kidney Disease Improving Global Outcomes. (Green: low risk; Yellow: moderately increased risk; Orange: high risk; Red, very high risk).

Figure 3

Results from the Fine and Gray subdistribution hazard model stratified by sex. ∗Adjusted for age, sex, race, cause and vintage of CKD, baseline comorbidities including diabetes, CVD-related comorbidities, respiratory diseases and cancer, baseline usage of immunosuppressive medication, Renin-angiotensin-aldosterone system inhibitors (RAASi; angiotensin-converting-enzyme inhibitors and Angiotensin receptor blockers) and sodium-glucose cotransporter-2 (SGLT2) inhibitors. CKD-EPI, Chronic Kidney Disease Epidemiology Collaboration; eGFR, estimated glomerular filtration rate; KFRE, Kidney Failure Risk Equation.

Figure 4

Difference in KFRE 2-year risk score calculated using CKD-EPI 2009 and 2021 equations by age and sex. CKD-EPI, Chronic Kidney Disease Epidemiology Collaboration; eGFR, estimated glomerular filtration rate; KFRE, Kidney Failure Risk Equation.

Figure 5

Distribution of KFRE 2-year risk calculated using eGFR from CKD-EPI 2021 versus 2009 equation. CKD-EPI, Chronic Kidney Disease Epidemiology Collaboration; eGFR, estimated glomerular filtration rate; KFRE, Kidney Failure Risk Equation.