Whole blood viscosity is associated with reduced myocardial mechano-energetic efficiency in nondiabetic individuals

Introduction: This cross-sectional study aimed to investigate the association between myocardial mechano-energetic efficiency (MEE) and whole blood viscosity (WBV) in nondiabetic adults participating in the CATAnzaro MEtabolic RIsk factors (CATAMERI) study. Methods: 1143 participants underwent an oral glucose tolerance test and an echocardiogram for myocardial MEE per gram of left ventricular mass (MEEi) measurement. WBV was measured as: [0.12 × h] + [0.17 × (p-2.07)], where h is haematocrit and p is plasma protein levels. Results: Study population includes 595 males and 548 females with a mean age of 46 ± 12 years and a mean BMI of 30.0 ± 6.2 kg/m2 . Individuals with normal glucose tolerance were 63%, while those with impaired fasting glucose, impaired glucose tolerance and or the combination of both were 14.3%, 13% and 9.7%, respectively. A univariate analysis showed that MEEi was significantly associated with sex, age, smoking, BMI, waist circumference, total cholesterol, HDL, triglycerides, fasting glucose, fasting insulin, HOMA-IR index, glucose tolerance, C-reactive protein, haematocrit, haemoglobin, plasma protein and WBV. In a multivariable regression model including variables that were significantly associated with MEEi in univariate analysis, MEEi was associated with HOMA-IR (β = -0.144, p < .001), age (β = -0.140, p < .001), WBV (β = -0.129, p < .001) and glucose tolerance (β = -0.064, p = .04). The independent association between WBV and MEEi remained statistically significant (β = -0.122, p < .001) when antihypertensive therapy and lipid-lowering therapy were included in the model. Conclusion: WBV is associated with decreased myocardial MEE independently of other cardiovascular risk factors.