Racial Differences in Mortality Among Those with CKD

Abstract

Compared with white individuals, black individuals have a significantly higher risk for death in the general population but seem to have a survival advantage in the ESRD population. Data on the relationship of race to survival in early stages of chronic kidney disease (CKD) are inconsistent. This study evaluated racial differences in mortality among the adult participants of the Third National Health and Nutrition Examination Survey, a population-based survey of community-dwelling individuals. CKD was defined either by an estimated GFR Ͻ60 ml/min per 1.73 m 2 or by the presence of albuminuria, and this status was determined for 14,611 individuals, 2892 of whom were found to have CKD. Adjusting for age, gender, and race, risk for all-cause mortality among individuals with CKD was more than double that of individuals with normal renal function. In the subgroup with CKD, adjusting for age and gender, black individuals had a significantly higher risk for death, and this risk was modified by age; specifically, black individuals who were younger than 65 yr were 78% more likely to die than white individuals, whereas no significant differences in mortality were observed among individuals who were Ն65 yr of age. Further adjustment for cardiovascular risk factors and CKD stage did not materially change the results, but the hazard ratios were significantly attenuated after adjustment for socioeconomic factors. In conclusion, these data demonstrate racial/ethnic disparities in mortality among individuals with CKD. This higher risk for death in early stages of CKD may explain the apparent survival advantage observed among black individuals who live long enough to reach stage 5 CKD. 19: 140319: -141019: , 200819: . doi: 10.1681 In the general population, the cardiovascular and noncardiovascular mortality rates for black individuals are persistently higher than those for white individuals. [1][2][3] In contrast, studies among individuals who have stage 5 chronic kidney disease (CKD) and are undergoing maintenance dialysis have consistently shown that black individuals have a survival advantage compared with white individuals. 4,5 Even though some studies in the general population have shown lower mortality rates among Mexican Americans despite a higher prevalence of cardiovascular risk factors and lower socioeconomic status ("Hispanic paradox"), studies with more complete follow-up demonstrated poorer outcomes in this ethnic group when compared with non-Hispanic white individuals. 2,6,7 In contrast, Hispanic individuals with stage 5 CKD also seem to have a survival advantage. 5,8 Despite various hypotheses, these paradoxic disparities with survival advantages for racial/ethnic minorities undergoing maintenance dialysis have not been satisfactorily explained. J Am Soc Nephrol

Cardiovascular Disease Among Hispanics and Non-Hispanics in the Chronic Renal Insufficiency Cohort (CRIC) Study

“…However, the composition of the HCRIC cohort is reflective of the heterogeneity of the U.S. Hispanic population in terms of country of origin and education (1,8,41). Moreover, the socioeconomic disadvantages observed in HCRIC are similar to those found in Hispanics with CKD in a recent NHANES III analysis (8). Also, findings from our cohorts may not be generalizable to all types to kidney disease, such as glomerulonephritis.…”

“…However, this methodology is commonly used in clinical research, and the excellent or substantial agreement between self-reported CHD and the medical record has been previously demonstrated in patients with ESRD (42). Third, we estimated GFR using the MDRD formula, which has not been validated in Hispanics; however, this formula has been used in other studies of Hispanics with CKD (8,43).…”

“…In a large group of individuals with stage 3 or 4 CKD enrolled in Kaiser Permanente of Northern California, Hispanic ethnicity was associated with a lower risk of cardiovascular events and death relative to non-Hispanic Caucasians despite experiencing a higher risk of ESRD (7). In contrast, a study of a nationally representative sample of the U.S. population, the third National Health and Nutrition Examination Survey (NHANES III), demonstrated a nonsignificant trend toward higher mortality in Mexican Americans with CKD than non-Hispanic Caucasians (8). These heterogeneous findings may be due to differences in the populations studied and methodology but underscore the need for further investigation.…”

Interstate Variation in Receipt of Nephrologist Care in US Patients Approaching ESRD

“…The lower rate of receiving nephrologist care by the younger black patients with CKD, as described in this study, may be responsible, in part, for their poor outcomes reported in the literature (44)(45)(46)(47). Novel strategies aimed at improving pre-ESRD care for younger black patients and implemented both nationally and at the state level could have far-reaching effects.…”

Prevalence and Predictive Value of Hypoalbuminemia in Appalachians With Chronic Kidney Disease

“…Thus, geographic distance from health care may be a contributing factor, though the high incident rate of non-diabetic ESRD among West Virginians remains largely unexplained. Studies associating CKD with poverty in the US largely invoke race as a contributing factor with African Americans and other ethnic minorities generally faring worse than whites, particularly when of lower affluence [14][15][16][17][18][19][20][21]. As reflected in our CKD cohort, a high proportion of West Virginia's population is non-Hispanic white (93.5% vs 65.6% for US) with a low prevalence of African Americans (3.6% vs 12.8% for US) [5,6].…”