Comparative analysis of red cell distribution width and high sensitivity C-reactive protein for coronary heart disease mortality prediction in multi-ethnic population: findings from the 1999-2004 NHANES.

BACKGROUND: Red cell distribution width (RDW) has been shown to predict all-cause and cardiovascular (CVD) mortality. However, the predictive ability of RDW for future coronary heart disease (CHD) mortality in comparison to high sensitivity C-reactive protein (hs-CRP) has not been assessed in a population cohort free of CVD.

METHODS: Analysis was performed on 8,513 adult participants (age > 20 years) free of CVD from the National Health and Nutrition Examination Surveys 1999-2004. Cox-proportional hazard analyses were used to assess the role of RDW and hs-CRP in CHD mortality and in subgroups based on high and low RDW and hs-CRP.

RESULTS: On adjustment for traditional risk factors (age, sex, systolic blood pressure, anti-hypertensive medication use, total cholesterol, high density lipoprotein cholesterol, lipid lowering therapy, smoking, diabetes mellitus, anemia, mean corpuscular volume and nutritional deficiencies), RDW [hazard ratio (HR) 1.26 95% Confidence Interval (CI) [1.12-1.42] p < 0.001] remained an independent predictor, while hs-CRP [HR 1.18 95% CI [0.98-1.41] p = 0.077] did not. On comparative analysis, high RDW (> 12.6%) was predictive of CHD mortality irrespective of hs-CRP status [hs-CRP ≤ 3 mg/L (HR 1.17 95% CI [1.01-1.36] p = 0.031)] and hs-CRP > 3 mg/L (HR 1.44 95% CI [1.23-1.68] p < 0.001). Hs-CRP was not predictive in either high or low RDW subgroup.

CONCLUSION: RDW but not hs-CRP was associated with CHD mortality independent of traditional risk factors in a cohort with no pre-existing CVD. RDW may be considered a stronger biomarker for CHD death than hs-CRP and needs further prospective evaluation in CVD risk assessment.