This proposal represents our continuing efforts to contribute to NIDDK's Strategic Plan to eliminate racial and ethnic disparities in chronic kidney disease (CKD), including end-stage renal disease (ESRD; stage 5 CKD). Despite extensive research over the last two decades, critical knowledge gaps persist. First, African Americans (AAs) and Hispanics continue to have 2-3 times higher incidence of ESRD than non-Hispanic whites (whites), but paradoxically have much better survival than whites after reaching ESRD and undergoing dialysis. Speculation is that this apparent survival advantage is related to survival disadvantage and inadequate care for AAs and Hispanics during the pre-ESRD period, but confirming this has been hampered by methodological challenges. Second, we still do not understand how differences in mortality between minorities and whites evolve over time as the disease advances. And third, we do not fully grasp how processes of care, which are potentially modifiable and vital to improving outcomes, affect survival selections among minorities (vs. whites). To close these longstanding knowledge gaps, we propose to conduct the first event-history analysis of national incident CKD populations to examine in-depth racial/ethnic disparities in outcomes and processes of care over the full course of CKD. Our central hypothesis is that differences in mortality between minorities (AAs and Hispanics) and whites are time-dependent over the course of CKD, and that differences in ESRD are related to the differences in pre-ESRD, which result from differential survival-selection processes between the groups. The analyses proposed under our three Specific Aims will test this and other specific hypotheses and examine a range of factors for the differential survival selections, particularly the processes of care.
Aim 1 will yield a detailed characterization of how racial/ethnic differences in mortality evolve over the full course of CKD.
Aim 2 will examine the effect of processes of care on differential survival selections among racial/ethnic groups, which drives the time-dependent changes found in Aim 1.
Aim 3 will assess the role of unexplained risks in these differential survival-selection processes. In addition to our novel hypotheses and innovative analytic approaches, this study will foster methodological advances in CKD research, which include the use of 1) two national incident CKD cohorts with >15 years of follow-up that connect the pre-ESRD and ESRD periods?the national veteran CKD population (>1.3 million) for primary analyses, and the Medicare CKD population (>790,000) for further understanding of processes of care across the nation; and 2) advanced statistical techniques, including time-dependent multi-state survival models and frailty models. This study will offer novel understanding of why differential survival rates among AAs and Hispanics vs. whites exist and how they can be addressed. Our results for real-world processes of care among AAs and Hispanics can be directly translated into actionable initiatives to enhance care for minority CKD patients. Building on our team's outstanding record, we anticipate that our efforts will continue to be novel, productive and highly impactful. .
Racial/ethnic disparities have persisted in multiple aspects of chronic kidney disease (CKD), including end- stage renal disease (ESRD), from processes and quality of care to incidence of ESRD and outcomes. We will perform event-history analyses of large incident CKD cohorts to critically examine the causes of the racial/ethnic disparities along the entire spectrum from pre-ESRD to ESRD. Understanding the sources of these disparities will serve to minimize them and improve the care of minority patients with CKD/ESRD.