While whole blood viscosity (WBV) has been shown to be related to the pathogenesis of various diseases, including cardiovascular diseases, laboratory measurement of WBV is time consuming and tedious. WBV can be estimated reliably from simple and frequently used laboratory tests. However, whether estimated WBV is also associated with increased allcause mortality and cardiovascular (CV) mortality has not been examined.
We used the Third National Health and Nutrition Examination (NHANES III) Survey (19881994) to examine association between estimated WBV and allcause and cardiovascular mortality. Vital status and cause of death until Dec 31, 2006 were obtained from the National Death Index. We estimated WBV at six shear rates (208/sec to 0.1/sec) using equations reported by de Simone et al. We used Cox proportional hazards model to calculate hazards ratio (HR) and 95% confidence interval (CI) in 6,940 participants who were older than 20 years and were free of clinical CV disease at baseline. We further validated our results in an independent sample (N=4946) from the Continuous NHANES (19992002).
There were 2,305 (33%) allcause deaths and 960 (14%) CV deaths during the followup (median followup 13.7 years; range 0 to 18). The mean (SD) age of the participants was 59 (13) years, 51% were females, 50% were Caucasians, 23% were current smokers, and 35% had history of hypertension. Unadjusted analyses found a significant association between WBV at all shear rates and allcause and CV mortality (HR: 1.23, 95%CI: 1.17 to 1.30 and HR: 1.26, 95%CI: 1.16 to 1.38 respectively for each 1SD increase in WBV at shear rate of 208/sec). This association remained statistically significant after adjusting for age, sex, race, CRP, diabetes, systolic blood pressure, smoking status, glomerular filtration rate, LDL cholesterol, red cell distribution width, and ALT; HR for all cause mortality: 1.10, 95%CI: 1.01 to 1.19 and HR for CV mortality: 1.15, 95%CI: 1.04 to 1.27. In the independent validation sample, there were 550 (11%) all cause deaths and 211 (4.3%) CV deaths. WBV was associated with allcause mortality and CV mortality in unadjusted analysis and with CV mortality in adjusted analysis; WBV was not associated with allcause mortality in the adjusted analysis although the effect estimate was in the similar direction (Table).
WBV, even when estimated from routine laboratory tests, remains an independent predictor of allcause and CV mortality and may identify highrisk individuals. The utility of WBV in predicting mortality needs further study.
Table 1Hazard ratios of allcase and cardiovascular mortality per one standard deviation increase in whole blood viscosity (WBV) in the discovery (NHANES III) and in the validation (Continuous NHANES) samples at two extreme shear rates
|WBV shear rate||Discovery Sample (6940)||Validation Sample (N=4946)|
|Allcause (2305)||Cardiovascular (960)||Allcause (550)||Cardiovascular (211)|
|208/sec||1.23 (1.17, 1.30)||1.26 (1.16, 1.38)||1.16 (1.06, 1.26)||1.25 (1.01, 1.55)|
|0.1/sec||1.24 (1.17, 1.31)||1.27 (1.16, 1.39)||1.16 (1.06, 1.26)||1.26 (1.01, 1.56)|
|208/sec||1.10 (1.01, 1.19)||1.15 (1.04, 1.27)||1.03 (0.94, 1.13)||1.23 (1.0, 1.51)|
|0.1/sec||1.10 (1.01, 1.20)||1.16 (1.05, 1.28)||1.03 (0.94, 1.13)||1.23 (1.0, 1.51)|
To cite this abstract:Adomaityte J, Qayyum R. Whole Blood Viscosity Is an Independent Predictor of Allcause and Cardiovascular Mortality. Abstract published at Hospital Medicine 2012, April 1-4, San Diego, Calif. Abstract 97646. Journal of Hospital Medicine. 2012; 7 (suppl 2). https://www.shmabstracts.com/abstract/whole-blood-viscosity-is-an-independent-predictor-of-allcause-and-cardiovascular-mortality/. Accessed July 22, 2019.