Correlation between insulin resistance surrogates and echocardiographic findings in asymptomatic patients with morbid...

To assess the relationship between insulin resistance (IR) and left ventricular diastolic dysfunction (LVDD) in asymptomatic patients with morbid obesity (MO).

The study cohort consisted of 231 patients (165 women and 66 men) with MO (mean body mass index [BMI] of 46.0 kg/m2) and a control group of 93 age-and sex-matched apparently healthy control subjects (56 women and 37 men; mean BMI of 24.1 kg/m2). Tissue Doppler imaging echocardiography was used to provide measurements of ejection fraction, LVDD (peak early tissue Doppler velocity/peak late tissue Doppler velocity or Em/Am ratio), left ventricular mass (LVM), and left ventricular hypertrophy (LVH). Adiponectin levels, the homeostasis model assessment index, and the ratio of triglycerides to high-density lipoprotein cholesterol (TG/HDL) were used as surrogate markers of IR.

The ejection fraction was normal and similar in the patient and control groups. LVDD (Em/Am ratio <1.0) and LVH prevalences were 52% and 30%, respectively, in the group with MO (significantly higher than in the control group; P<0.0005). The patients with MO displayed higher IR on the basis of all 3 surrogate markers (P<0.0005, respectively). Log-transformed adiponectin showed the strongest correlations with LVM and Em/Am ratios; log-transformed homeostasis model assessment index and TG/HDL ratio displayed less robust yet significant correlations. Stepwise multiple linear regression analysis identified hypertension and the TG/HDL ratio as independent predictors of 35.5% of the variance of LVDD. In contrast, LVM was mainly predicted by BMI, hypertension, and sex.

LVH and LVDD are highly prevalent in asymptomatic patients with MO. IR is significantly correlated with both variables. Furthermore, LVDD is independently predicted by the presence of hypertension and the TG/HDL ratio. The prognostic implications of these findings warrant further studies.