Waist circumference is a strong predictor of regional left ventricular dysfunction in asymptomatic diabetic patients: the factor-64 study

Background: Obesity is major health problem. Abdominal obesity is associated with the metabolic syndrome, coronary artery disease (CAD) and heart failure (HF). It is unclear if abdominal obesity is associated with left ventricular (LV) dysfunction independently of hypertension (HTN), CAD and weight among diabetes mellitus (DM) patients. Methods: FACTOR-64 was designed to evaluate the effect of an active diagnostic approach in asymptomatic DM patients on total and event-free survival. Participants were randomized to screening coronary CT angiography or standard of care. Overall, 200 consecutive patients randomized to screening also underwent 2-D echo with speckle tracking. Using offline software global systolic longitudinal strain (Ell) and early diastolic strain (E') were determined from apical 2 and 4 chamber views. Relationship between waist circumference (WC) and regional LV function was studied. Results: Among the entire group (mean age = 60 years, females= 50%, HTN =79%), body mass index (BMI) was 32 kg/m2 and WC was 108 cm. Median coronary calcium score (CCS) was 27 Agatston units, ejection fraction 67%, global Ell: -12.9%, and peak E' was 0.81 sec- 1. Greater WC was associated with progressively worse global strain (Ell in the lowest WC quartile was -14.6% vs highest quintile: -11.4%, p<0.0001 for trend). This association was seen in both genders (in women p=0.001 and men p=0.0003, for trend). The relation between Ell and WC remained significant after multivariable adjustment for age, gender, CAD severity, CCS, DM type, HTN and systolic blood pressure (beta=0.1 %/cm, p<0.001). After including either weight or BMI in the regression model, only WC remained an independent predictor of global Ell (p=0.001, and 0.003 after including weight and BMI, respectively), while weight and BMI became non-significant (p= 0.81 and 0.65, respectively). Conclusions: Abdominal obesity expressed as increased waist circumference is associated with progressively lower global systolic strain in DM patients. This relation is independent of age, gender, risk factors, calcium score, and extent of CAD. Waist circumference appears to be stronger predictor of regional LV function than body weight or BMI.