(162) Decreased Hazard of Potassium Lowering Drug Prescription Receipt Following Implementation of the 2021 CKD-EPI Creatinine GFR Equation

Background: Chronic kidney disease (CKD) affects 14.8% of the US population; patients with CKD are at high risk for hyperkalemia, which can lead to arrythmias and cardiac arrest. The hyperkalemia risk is highest in patients with comorbid type 2 diabetes (T2D) and/or hypertension; management with potassium-lowering drugs is essential to decrease poor cardiovascular outcomes and allow patients to continue CKD treatment. Changes to the CKD-EPI creatinine GFR calculation in 2021 influenced time to diagnosis, especially for Black patients.

Objectives: To understand changes in time to prescription of potassium-lowering drugs after vs. before the implementation of the race-free 2021 CKD-EPI creatinine GFR calculation.

Methods: Using a subset of EHR data from Truveta, we identified a cohort of adult patients with a CKD diagnosis after December 2020, at least one encounter before diagnosis, and no medication dispense of a potassium lowering drug at or before diagnosis. EHR data from Truveta included conditions, prescriptions, and medication dispensing for a collective of US healthcare systems. We used 12/31/2021 as a proxy for the GFR calculation change. Patients diagnosed at or before this date (Group A) and after this date (Group B) were followed for one year after first CKD diagnosis, first prescription of a potassium-lowering drug, or until their last encounter, whichever occurred first. We used Cox proportional hazards models to compare time to first prescription for the two groups, adjusting for sex, age, race, income, education, T2D, hypertension, obesity, hyperlipidemia, and renal failure.

Results: 261,774 patients met the study criteria. 15% were Black and 52% were female. In adjusted models, Group B patients had a lower hazard of receiving a potassium-lowering drug (HR 0.87; CI 0.82, 0.93) than Group A patients. Black patients (HR 1.27; CI 1.17,1.38) and patients with diabetes (HR 1.82; CI 1.70,1.95) had a greater risk and patients with hypertension (HR 0.73; CI 0.68, 0.78) had a lower risk of being prescribed a potassium-lowering medication than their counterparts.

Conclusions: In the study population, the use of potassium-lowering drugs decreased after removing race from the CKD-EPI creatinine GFR calculation. One possible explanation is patients were more likely to be diagnosed with CKD at an earlier stage (especially among Black patients) after the formula change, and thus had a longer time to poor outcomes such as hyperkalemia, initiation of potassium-lowering drugs, or dialysis, among others. Further evaluation and of these trends should be a priority.