Time to Hyperkalemia and Other Outcomes Post-Implementation of the 2021 CKD-EPI Creatinine Equation: An Observational Cohort Study

BackgroundTimely diagnosis can delay progression to poor clinical outcomes and biomarker endpoints in CKD. Our objective was to analyze how the implementation of the 2021 CKD-EPI Creatinine Equation (CKD-EPI 2021) affected time to the doubling of serum creatinine, prescription or dispense of potassium-lowering drugs, hyperkalemia, and creation of arteriovenous graft fistula for dialysis within one year of CKD diagnosis. MethodsWe used retrospective EHR data to create two cohorts of adult patients based on date of diagnosis. We followed patients from their CKD diagnosis to the occurrence of each outcome, their last medical encounter, or 1-year post diagnosis, whichever occurred first. The first cohort was diagnosed in 2021 when the CKD-EPI 2009 Creatinine Equation (pre-update cohort) was recommended. The second cohort was diagnosed in 2022 when CKD-EPI 2021 (post-update cohort) was recommended. Multivariable models for the time relationship between cohort and each outcome were adjusted for demographics, social determinants of health, and comorbidities. As CKD-EPI 2021 was race-free, we also considered the interaction between cohort and race. ResultsWe found 261,774 patients with a first-time CKD diagnosis. After implementation of CKD-EPI 2021, patients were less likely to have a diagnosis of hyperkalemia, potassium-lowering drug prescription, a doubling of serum creatinine, or an arteriovenous graft fistula placement within a year of CKD diagnosis. Black patients in the post-update cohort were less likely to be diagnosed with hyperkalemia compared to Black patients in the pre-update cohort (AHR 0.83; CI 0.80, 0.86), but Black patients overall were significantly more likely than non-Black patients to have hyperkalemia. ConclusionsTime to poor clinical outcomes and biomarkers differs by the date of CKD diagnosis. Future work should elucidate the mechanisms driving these differences, whether there have been significant changes in treatment practices since the CKD-EPI 2021 recommendation, and long-term effects of each outcome.