Insulin resistance influences the impact of hypertension on left ventricular diastolic dysfunction in a community sample

Abstract

Background: Although obesity-associated metabolic abnormalities (insulin resistance-IR) may not play as marked a role in determining left ventricular (LV) diastolic dysfunction (DD) as hypertension, the impact of combinations of these risk factors on DD is unknown.

Hypothesis: We hypothesized that IR influences the impact of hypertension on DD.

Methods: In 704 randomly selected participants from a community sample with a high prevalence of hypertension (50.6%) and obesity (46.5%), we determined adiposity indices, IR from the homeostasis model (HOMA-IR) and LV diastolic function using standard echocardiographic techniques.

Results: HOMA-IR was independently associated with lateral wall e' and E/e' (P < 0.05 to P < 0.005) as well as a diagnosis of DD (P < 0.02). Importantly, however, an enhanced relationship between HOMA-IR and E/e' in hypertensives (n = 356, partial r = 0.15, P < 0.005) as compared to normotensives (n = 348, partial r = 0.02 P = 0.75) was noted. Consequently, as compared to normotensives, with adjustments for confounders, hypertension was independently associated with DD only in those with the highest tertile of HOMA-IR (odds ratio = 2.65, 95% confidence interval = 1.29-5.42, P < 0.01), while in those with the lowest tertile of HOMA-IR, hypertension failed to show a higher prevalence of DD (P = 0.22).

Conclusions: Insulin resistance enhances the impact of hypertension on LV DD. Thus, DD is more likely to occur with the combination of hypertension and IR.

Keywords: hypertension; insulin resistance; left ventricular diastolic function; obesity.

Figure 1

Multivariate adjusted indices of left ventricular diastolic function in normotensives and across tertiles of the homeostasis model of insulin resistance (HOMA‐IR) (upper panel), waist circumference (WC) (middle panel) or body mass index (BMI) (lower panel) in hypertensives of a community sample. Adjustments are for age, sex, systolic blood pressure, pulse rate, regular smoking, regular alcohol consumption, and diabetes mellitus. Tertiles of HOMA‐IR, WC, and BMI are defined Table S3. *P < 0.02, **P < 0.001, ***P < 0.0001 vs normotensives. †P < 0.05 vs hypertensives HOMA‐IR tertile 1 or vs hypertensives waist circumference tertile 1. e', myocardial tissue lengthening in early diastole at the mitral annulus; E/e', transmitral early blood flow velocity/velocity of the mean value of lateral and septal wall myocardial tissue lengthening in early diastole at the mitral annulus; LV, left ventricle

Figure 2

Impact of insulin resistance (homeostasis model‐homeostasis model of insulin resistance [HOMA‐IR]), waist circumference (WC) or body mass index (BMI) on the odds of independent associations between hypertension and left ventricular diastolic dysfunction. Adjustments in the left panels are for age, sex, pulse rate, regular smoking, regular alcohol consumption, and diabetes mellitus. Tertiles of HOMA‐IR, WC, and BMI are defined in Table S3