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 < 60 ml/min per 1.73 m2 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 > or = 65 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.

Figure 1.

Flow diagram illustrating how the cohort was built for analyses for this study from the 18,825 participants who were ≥20 yr of age in the NHANES III.

Figure 2.

(A) Effect of age on the differences in outcomes among whites and black individuals with CKD enrolled in the NHANES III. The HR for all-cause mortality, adjusted for age and gender, among black individuals in different age categories were as follows: <65 yr 1.78 (95% CI 1.14 to 2.78); 65 to 75 yr 1.12 (95% CI 0.89 to 1.42) and >75 yr 0.94 (95% CI 0.76 to 1.17). (B) Effect of age on the differences in outcomes among white and Mexican American individuals with CKD enrolled in the NHANES III. The HR for all-cause mortality, adjusted for age and gender, among Mexican Americans in different age categories were as follows: <65 yr 1.35 (95% CI 0.94 to 1.94); 65 to 75 yr 1.03 (95% CI 0.76 to 1.40); and >75 yr 0.72 (95% CI 0.44 to 1.17).