Racial and ethnic differences in mortality of hemodialysis patients: role of dietary and nutritional status and inflammation

Abstract

Background: Racial/ethnic disparities prevail among hemodialysis patients. We hypothesized that significant differences exist between Black and non-Hispanic and Hispanic White hemodialysis patients in nutritional status, dietary intake and inflammation, and that they account for racial survival disparities.

Methods: In a 6-year (2001-2007) cohort of 799 hemodialysis patients, we compared diet and surrogates of nutritional-inflammatory status and their mortality-predictabilities between 279 Blacks and 520 Whites using matched and regression analyses and Cox with cubic splines.

Results: In age-, gender- and diabetes-matched analyses, Blacks had higher lean body mass and serum prealbumin, creatinine and homocysteine levels than Whites. In case-mix-adjusted analyses, dietary intakes in Blacks versus Whites were higher in energy (+293 ± 119 cal/day) and fat (+18 ± 5 g/day), but lower in fiber (-2.9 ± 1.3 g/day) than Whites. In both races, higher serum albumin, prealbumin and creatinine were associated with greater survival, whereas CRP and IL-6, but not TNF-α, were associated with increased mortality. The highest (vs. lowest) quartile of IL-6 was associated with a 2.4-fold (95% CI: 1.3-3.8) and 4.1-fold (2.2-7.2) higher death risk in Blacks and Whites, respectively.

Conclusions: Significant racial disparities exist in dietary, nutritional and inflammatory measures, which may contribute to hemodialysis outcome disparities. Testing race-specific dietary and/or anti-inflammatory interventions is indicated.

Fig. 1

Cubic spline models of the Cox proportional regression analyses reflecting adjusted mortality-predictability (with 95% CI) according to predialysis serum albumin in African-American (upper panel) vs. White (Hispanic and non-Hispanic, lower panel) MHD patients over 6 years. Spline models are with 2 degrees of freedom. Case-mix includes age, gender, diabetes mellitus, Charlson comorbidity index score and dialysis vintage.

Fig. 2

Cubic spline models of the Cox proportional regression analyses reflecting adjusted mortality-predictability (with 95% CI) according to predialysis serum prealbumin in African-American vs. White (Hispanic and non-Hispanic) MHD patients over 6 years. Spline models are with 2 degrees of freedom. Case-mix includes age, gender, diabetes mellitus, Charlson comorbidity index score and dialysis vintage.

Fig. 3

Cubic spline models of the Cox proportional regression analyses reflecting adjusted mortality-predictability (with 95% CI) according to predialysis serum creatinine in African-American vs. White (Hispanic and non-Hispanic) MHD patients over 6 years. Spline models are with 2 degrees of freedom. Case-mix includes age, gender, diabetes mellitus, Charlson comorbidity index score and dialysis vintage.

Fig. 4

Cubic spline models of the Cox proportional regression analyses reflecting adjusted mortality-predictability (with 95% CI) according to predialysis serum CRP in African-American vs. White (Hispanic and non-Hispanic) MHD patients over 6 years. Spline models are with 2 degrees of freedom. Case-mix includes age, gender, diabetes mellitus, Charlson comorbidity index score and dialysis vintage.

Fig. 5

Cubic spline models of the Cox proportional regression analyses reflecting adjusted mortality-predictability (with 95% CI) according to predialysis serum IL-6 in African-American vs. White (Hispanic and non-Hispanic) MHD patients over 6 years. Spline models are with 2 degrees of freedom. Case-mix includes age, gender, diabetes mellitus, Charlson comorbidity index score and dialysis vintage.

Fig. 6

Cubic spline models of the Cox proportional regression analyses reflecting adjusted mortality-predictability (with 95% CI) according to predialysis serum TNF-α in African-American vs. White (Hispanic and non-Hispanic) MHD patients over 6 years. Spline models are with 2 degrees of freedom. Case-mix includes age, gender, diabetes mellitus, Charlson comorbidity index score and dialysis vintage.