Racial Differences and Contributory Cardiovascular and Non-cardiovascular Risk Factors Towards Chronic Kidney Disease Progression In Young To Middle-Aged Black And White American Adults

Background The progression of chronic kidney disease (CKD) is higher in Black than in White Americans but studies have mainly focused on racial differences within advanced CKD. We evaluated CKD progression in Black and White participants over 20 years and the contribution of conventional cardiovascular and non-traditional risk factors to racial disparities in CKD progression. Methods This study was based on 2,175 Black and 2,207 White adults in the Coronary Artery Risk Development in Young Adults (CARDIA) study. Both estimated glomerular filtration rate (eGFR) and urinary albumin-to-creatinine ratio (UACR) were measured at study year 10 (age 27-41y) and every five years for 20 years. The outcome was CKD progression through No CKD into Low, Moderate, High, or Very High Risk that was based on categories of eGFR and UACR in combination. The association between race and CKD progression as well as the contribution of risk factors to racial differences were assessed in multivariable-adjusted Cox proportional hazards models. Results Black participants had higher CKD transition probabilities than White participants and more prevalent risk factors during the 20-year period studied. Hazard ratios for CKD transition for Black (vs White participants) were 1.38 from No CKD into ≥ Low Risk, 2.25 from ≤ Low Risk into ≥ Moderate Risk, and 4.49 for from ≤ Moderate Risk into ≥ High Risk. Racial differences in CKD progression from No CKD into ≥ Low Risk were primarily explained by forced vital capacity (54.8%), hypertension (30.9%), and obesity (20.8%). Similar findings were observed for the race difference in transition from ≤ Low Risk into ≥ Moderate Risk, but little of the race difference in transition ≤ Moderate Risk into ≥ High Risk was explained. Conclusions In this longitudinal study, Black compared to White participants had a higher risk of CKD progression, and this discrepancy may be partly explained by conventional cardiovascular and non-traditional risk factors. What Is New? What Are the Clinical Implications? ### Competing Interest Statement HK has served as a consultant for Bayer pharmaceuticals and CSL Vifor and was a past president of the National Kidney Foundation. AC has served as a consultant for Novartis, Reata, Amgen, and Relypsa. Other authors declare no relevant financial interest. ### Clinical Trial None ### Funding Statement The Coronary Artery Risk Development in Young Adults Study (CARDIA) is conducted and supported by the National Heart, Lung, and Blood Institute (NHLBI) in collaboration with the University of Alabama at Birmingham (HHSN268201800005I & HHSN268201800007I), Northwestern University (HHSN268201800003I), University of Minnesota (HHSN268201800006I), and Kaiser Foundation Research Institute (HHSN268201800004I). This manuscript has been reviewed by CARDIA for scientific content. The sponsor, NHLBI has a representative on the Steering Committee of CARDIA and participated in study design, data collection, and scientific review of this paper. The sponsor had no role in data analysis, data interpretation, or writing of this report. The data used in this study are available from the CARDIA Coordinating Center ([www.cardia.dopm.uab.edu][1]) on reasonable request. ### 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: Single IRB at the University of Alabama Birmingham 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 and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes Data used in this paper are available on reasonable request from the CARDIA Coordinating Center, [1]: http://www.cardia.dopm.uab.edu