Effects of Changes in Calculating GFR Using KDIGO Standards: Discordance in the Staging and Timing of Diagnosis of Chronic Kidney Disease

Introduction Chronic kidney disease (CKD) is a highly prevalent disease with disparities in diagnosis and treatment. Until recently, primary diagnosis for CKD was based on equations that incorporated race and have demonstrated racial bias. This study had two aims comparing outcomes for Black patients and their counterparts: 1) whether using the new 2021 CKD-EPI equation led to decreased disparity with time to diagnosis; and 2) whether there was discordance in the staging between the two equations at potential diagnosis point. Methods We evaluated patients aged 18 and over with non-hospitalization related serum creatinine laboratory results between January 1, 2016 and September 30, 2023. We estimated the GFR for each patient using the 2009 and 2021 CKD-EPI creatinine equations. We assessed stage discordance for stages 3a, 3b, 4, and 5 using chi-square tests and the Cochran-Mantel-Haenszel. We used multivariate logistic regression to assess a change in staging based on the equation used. Results 15.5% of the 8,080,889 patients included in this study were Black. The median age was 57 years and 15.3% of patients met the criteria for stage 3a CKD or higher using either equation. Discordance in staging by equation and by race existed, especially for Black patients at stages 3a and 3b. 40% of Black patients identified as stage 4 using the 2021 equation were 3b or lower using the 2009 equation. Discussion Well established medical algorithms with race components are being re-examined. We found more disparity with the initial staging of the disease. The disconnect in the timing of staging by equation for Black patients means a number of these patients may not have received the appropriate treatment. Future work should elucidate the impact of the change in CKD staging with the 2021 CKD-EPI creatinine equation on treatment. Conclusion Significant disparity exists in the timing and staging of CKD by CKD-EPI equation and by race. ### Competing Interest Statement All authors are employees of Truveta. ### Funding Statement This study did not receive any funding. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Normalized electronic health record data are de-identified by expert determination under the HIPAA Privacy Rule before being made available to researchers. In accordance with 46.101 Protection of Human Subjects, our study did not require Institutional Review Board approval because it used only deidentified medical records. All data used in this study are publicly available to all Truveta subscribers and may be accessed at studio.truveta.com. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data used in this study is available to subscribers at studio.truveta.com.