Association of Impaired Glucose Regulation and Insulin Resistance with Cardiac Structure and Function: Results from ECHO-SOL (Echocardiographic Study of Latinos)

Background - We examined the relationship between glucose homeostasis and comprehensive measures of cardiac structure and function among a representative sample of US Hispanics. Methods and Results - ECHO-SOL (Echocardiographic Study of Latinos), an echocardiographic ancillary study of the HCHS/SOL (Hispanic Community Health Study/Study of Latinos), enrolled 1818 Hispanic/Latino men (43%) and women (57%) aged ≥45 years (mean=56). Glucose intolerance was defined as follows: (1) prediabetes: hemoglobin (HbA1c) ≥5.7 and <6.5% and (2) diabetes mellitus: fasting plasma glucose ≥126 mg/dL, 2-hour postload glucose ≥200 mg/dL, HbA1c ≥6.5%, or hypoglycemic agent use. Uncontrolled diabetes mellitus was defined as HbA1c ≥7.0%. Insulin resistance was defined using the homeostatic model assessment for insulin resistance. Echocardiography examinations assessed left ventricular structure and systolic/diastolic function. Multivariable linear and logistic regression models were used. Prediabetes prevalence was 42%, and diabetes mellitus prevalence was 28% (47% uncontrolled). Glucose intolerance was associated with increased left ventricular posterior wall and interventricular septal and relative wall thicknesses (all P<0.05), reduced ejection fraction (P<0.01), reduced stroke and end-diastolic volumes (both P<0.001), decreased peak E′ velocity (lateral and septal P<0.001), and increased E/E′ ratio (lateral and septal P<0.01). The odds ratios (95% confidence intervals) for diastolic dysfunction among individuals with prediabetes and diabetes mellitus (versus diabetes mellitus free) were 1.36 (0.96-1.9) and 1.90 (1.3-2.8), respectively(P=0.006). Results were consistent for uncontrolled diabetes mellitus versus diabetes mellitus. Homeostatic model assessment for insulin resistance was associated with increased E/E′ (P<0.001), and greater relative wall thickness and septal thickness (both P<0.05); lower stroke volume (P<0.0001); and lower peak lateral and septal E′ velocities (both P<0.01). Conclusions - Glucose intolerance and insulin resistance are associated with unfavorable cardiac structure and function, particularly worsened measures of diastolic function, even before the development of diabetes mellitus.