Cardiac Structural Remodeling, Longitudinal Systolic Strain, and Torsional Mechanics in Lean and Nonlean Dysglycemic Chinese Adults

Background: Diabetes mellitus and pre–diabetes mellitus are associated with lower body mass indices and increased risk of cardiovascular events (including heart failure) at lower glucose thresholds in Chinese compared with Western cohorts. However, the extent of cardiac remodeling and regulation on cardiac mechanics in lean and nonlean dysglycemic Chinese adults is understudied. Methods and Results: We studied 3950 asymptomatic Chinese (aged 49.7±10.7 years; 65% male; body mass index: 24.3±3.5 kg/m2 ) with comprehensive echocardiography including speckle tracking for left ventricular global longitudinal strain/torsion, with plasma sugar, glycosylated hemoglobin (HbA1c), and insulin resistance (homeostasis model assessment of insulin resistance) obtained. Participants were classified as (1) nondiabetic (fasting glucose <100 mg/mL; HbA1c <5.7%; n=1416), prediabetic (fasting glucose 100–126 mg/dL; HbA1c 5.7%–6.4%; n=2029), or diabetic (n=505) and (2) lean (body mass index <23 kg/m2 ; n=1445) or nonlean (n=2505). Higher sugar, HbA1c, and homeostasis model assessment of insulin resistance were independently associated with higher left ventricular mass, greater mass-to-volume ratio, more impaired diastolic indices, and worse global longitudinal strain even after adjusting for clinical covariates (adjusted coefficient value: 0.28/0.12 for global longitudinal strain per 1 U HbA1c/homeostasis model assessment of insulin resistance increment; bothP <0.001), with a consistent trend toward greater torsion (all trendP <0.001). The optimal cutoffs in identifying subclinical systolic dysfunction (global longitudinal strain more impaired than −18%) for lean versus nonlean individuals were 97 versus 106 mg/dL for fasting sugar, 130 versus 135 mg/mL for postprandial sugar, 5.62% versus 6.28% for HbA1c, and 1.81 versus 2.40 for homeostasis model assessment of insulin resistance, respectively.Conclusions: These data demonstrate the presence of preclinical cardiac remodeling and systolic dysfunction in prediabetic and diabetic Chinese adults, occurring at lower thresholds of glycemic indices than defined by international standards, particularly in lean individuals.