Red blood cell (RBC) parameters (hemoglobin [Hgb], hematocrit [Hct], mean corpuscular volume [MCV], and red cell distribution width [RDW]) are reported in complete blood count reports and have been hypothesized to be associated with cardiovascular diseases. However, these association have not been reported in a large cohort of healthy US adults with longterm followup.
We used the Third National Health and Nutrition Examination Survey III (NHANES III) to examine association between RBC parameters and allcause and cardiovascular (CV) mortality. Causespecific mortality status of participants was obtained by matching to the National Death Index with followup through December 31, 2006. Participants younger than 20 years of age, with cardiovascular diseases, or with abnormal hemoglobin levels (17.2>Hgb<13.8 g/dL for men, 12.1>Hgb<15.1 g/dL for women) were excluded. We used Cox proportional hazards model to calculate univariate and multivariable hazard ratios (HR) and 95% confidence interval (CI) in 12,050 participants. All analyses were performed in STATA (version 10.1 for Windows) taking into account the complex probability sampling survey design.
There were 3,029 allcause deaths and 1,349 CV deaths during the followup (median followup 14.2 years, range 018). The mean (SD) age of the participants was 48 (19) years, 52% were females, 26% were active smokers at baseline, and 37% had history of hypertension. Mean (SD) Hgb was 14.2 (1.2) g/dL, HCT 42.3(3.4)%, MCV 89.9(4.7) fL, and RDW 13.0 (0.89)%. All RBC parameters were significantly associated with allcause mortality in unadjusted analysis. Hct, MCV, and RDW remained significantly associated with allcause mortality after adjustment for age, sex, race, creactive protein, diabetes, hypertension, smoking status, glomerular filtration rate, and LDL cholesterol. For CV mortality, Hgb, Hct, and RDW were statistically significant with CV mortality in unadjusted analysis but only RDW remained statistically significant after adjustment for confounding variables. In adjusted analysis, subjects with RDW in the fourth quartile (mean RDW=14.1%) were at 46% higher risk for allcause mortality and 59% higher for CV mortality (HR =1.46, 95%CI = 1.21 to 1.76 and 1.59, 95%CI = 1.24 to 2.02 respectively) than subjects in the first quartile (mean RDW =12.1%).
While Hct, MCV, and RDW are associated with allcause mortality, only RDW is associated with both allcause and CV mortality independent of traditional CV risk factors. Role of RDW in predicting future cardiovascular events in healthy individuals needs further study.
Table 1Hazard ratios (HR) of red blood cell parameters for allcause and cardiovascular (CV) mortality
|Variable||Allcause Mortality||CV Mortality|
|Hemoglobin (g/dL)||1.20 (1.14, 1.26)||<0.001||1.19 (1.10, 1.28)||<0.001|
|Hematocrit (%)||1.07 (1.05, 1.08)||<0.001||1.07 (1.04, 1.10)||<0.001|
|Mean Corpuscular volume (fL)||1.02 (1.01, 1.03)||<0.001||1.00 (0.99, 1.02)||0.57|
|Red cell distribution width (%)||1.24 (1.15, 1.34)||<0.001||1.25 (1.14, 1.37)||<0.001|
|Hemoglobin (g/dL)||1.07 (0.99, 1.15)||0.09||1.00 (0.91, 1.10)||0.96|
|Hematocrit (%)||1.03 (1.00, 1.06)||0.02||1.02 (0.99, 1.05)||0.17|
|Mean Corpuscular volume (fL)||1.02 (1.01, 1.03)||0.004||1.00 (0.97, 1.02)||0.67|
|Red cell distribution width (%)||1.16 (1.07, 1.25)||<0.001||1.19 (1.09, 1.29)||<0.001|
Figure 1KaplanMeir survival curves of participants in the lowest (1st) and uppermost (4th) quartile of red cell distribution width.
To cite this abstract:Adomaityte J, Qayyum R. Red Blood Cell Parameters Are Independent Risk Predictors of Allcause and Cardiovascular Mortality Among Healthy Us Adults. Abstract published at Hospital Medicine 2012, April 1-4, San Diego, Calif. Abstract 97644. Journal of Hospital Medicine. 2012; 7 (suppl 2). https://www.shmabstracts.com/abstract/red-blood-cell-parameters-are-independent-risk-predictors-of-allcause-and-cardiovascular-mortality-among-healthy-us-adults/. Accessed June 17, 2019.