Red Blood Cell Parameters Are Independent Risk Predictors of Allcause and Cardiovascular Mortality Among Healthy Us Adults

Meeting: Hospital Medicine 2012, April 1-4, San Diego, Calif.

Abstract number: 97644

Background:

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 long–term follow–up.

Methods:

We used the Third National Health and Nutrition Examination Survey III (NHANES III) to examine association between RBC parameters and all–cause and cardiovascular (CV) mortality. Cause–specific mortality status of participants was obtained by matching to the National Death Index with follow–up 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.

Results:

There were 3,029 all–cause deaths and 1,349 CV deaths during the follow–up (median follow–up 14.2 years, range 0–18). 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 all–cause mortality in unadjusted analysis. Hct, MCV, and RDW remained significantly associated with all–cause mortality after adjustment for age, sex, race, c–reactive 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 all–cause 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%).

Conclusions:

While Hct, MCV, and RDW are associated with all–cause mortality, only RDW is associated with both all–cause 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 all–cause and cardiovascular (CV) mortality

Variable All–cause Mortality CV Mortality
HR P–value HR P–value  
Unadjusted
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
Adjusted
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 1Kaplan–Meir survival curves of participants in the lowest (1st) and upper–most (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 December 13, 2019.

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