RATIONALE & OBJECTIVES Few studies have investigated racial disparities in survival among dialysis patients in a manner that considers risk factors and mortality during the phase of kidney disease before maintenance dialysis. Our objective was to explore racial variations in survival among dialysis patients and relate them to racial differences in comorbid conditions and rates of death in the setting of kidney disease not yet requiring dialysis therapy. STUDY DESIGN Retrospective cohort study. SETTINGS & PARTICIPANTS 3,288 black and white participants in the Chronic Renal Insufficiency Cohort (CRIC), none of whom were receiving dialysis at enrollment. EXPOSURE Race. OUTCOME Mortality. ANALYTIC APPROACH Cox proportional hazards regression was used to examine the association between race and mortality starting at: (1) time of dialysis initiation and (2) entry into the CRIC. RESULTS During 7.1 years of median follow-up, 678 CRIC participants started dialysis. Starting from the time of dialysis initiation, blacks had lower risk for death (unadjusted HR, 0.67; 95% CI, 0.51-0.87) compared with whites. Starting from baseline CRIC enrollment, the strength of the association between some risk factors and dialysis was notably stronger for whites than blacks. For example, the HR for dialysis onset in the presence (vs absence) of heart failure at CRIC enrollment was 1.30 (95% CI, 1.01-1.68) for blacks versus 2.78 (95% CI, 1.90-4.50) for whites, suggesting differential severity of these risk factors by race. When we included deaths occurring both before and after dialysis, risk for death was higher among blacks (vs whites) starting from CRIC enrollment (HR, 1.41; 95% CI, 1.22-1.64), but this finding was attenuated in adjusted models (HR, 1.08; 95% CI, 0.91-1.28). LIMITATIONS Residual confounding. CONCLUSIONS The apparent survival advantage among blacks over whites treated with dialysis may be attributed to selected transition of a subset of whites with more severe comorbid conditions onto dialysis.

中文翻译：

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CKD和透析中的种族和死亡率：慢性肾脏功能不全队列研究（CRIC）的发现。

理由和目的很少有研究以维持透析前在肾脏疾病阶段中考虑危险因素和死亡率的方式调查透析患者的生存差异。我们的目标是探讨透析患者生存中的种族差异，并将其与尚无透析治疗的肾脏疾病的合并症和死亡率的种族差异相关联。研究设计回顾性队列研究。背景和参与者慢性肾功能不全队列（CRIC）的3,288名黑人和白人参与者，入选时均未接受透析。曝光种族。结果死亡率。分析方法Cox比例风险回归用于检查种族与死亡率之间的关联，起始于：（1）开始透析的时间和（2）进入CRIC的时间。结果在7.1年的中位随访期间，有678位CRIC参与者开始了透析。从透析开始起，黑人与白人相比具有较低的死亡风险（未经调整的HR，0.67； 95％CI，0.51-0.87）。从基线CRIC入组开始，白人的某些危险因素与透析之间的关联强度明显强于黑人。例如，在CRIC入组时有心力衰竭（相对于无心衰）透析开始的HR（黑人）为1.30（95％CI，1.01-1.68），而白人为2.78（95％CI，1.90-4.50），表明存在差异这些种族危险因素的严重程度。当我们包括透析前后发生的死亡时，从CRIC入组开始，黑人（与白人）的死亡风险较高（HR，1.41；而CRIC为1）。95％CI，1.22-1.64），但在调整后的模型中这一发现有所减弱（HR，1.08； 95％CI，0.91-1.28）。局限性残余混杂。结论透析治疗后的黑人比白人具有明显的生存优势，这可能归因于患有更严重合并症的白人子集选择透析后的选择。