Echocardiographic epicardial adipose tissue thickness and coronary artery disease: a population-specific analysis

Background: Epicardial adipose tissue (EAT) is associated with coronary artery disease (CAD), but whether this relationship is linear and consistent across different demographic and metabolic subgroups remains unclear. Therefore, we aimed to characterize the dose-response pattern of this association and to examine its variation across key demographic and metabolic subgroups. Methods: In this retrospective cross-sectional study, we enrolled 1,021 consecutive symptomatic patients who underwent coronary angiography (CAG) and echocardiography. EAT thickness was measured at end-systole using transthoracic echocardiography. Multivariable logistic regression models were used to assess the association between EAT thickness and CAD, and a trend analysis was performed by categorizing EAT thickness into quartiles. Restricted cubic spline (RCS) analysis was performed to further characterize the dose-response relationship and test the linearity assumption. Interaction analyses were conducted to identify potential effect modifiers, and stratified analyses were additionally performed according to sex, age, hypertension, smoking status, HbA1c level, and HDL-C level. Results: Among the 1,021 patients, 646 were diagnosed with CAD and had higher EAT thickness than those without CAD. In the fully adjusted model, each 1-mm increase in EAT thickness was associated with a 16% higher odds of CAD [odds ratio (OR): 1.16; 95% confidence interval (CI): 1.07–1.26]. Compared with the lowest quartile, the highest quartile showed a markedly increased odds of CAD (OR: 2.14; 95% CI: 1.41–3.25), with a significant linear trend (P for trend =0.0024). RCS analysis further supported a linear dose-response relationship, showing no significant deviation from linearity (P for nonlinearity =0.544). Interaction analysis revealed a significant interaction between EAT thickness and BMI (P for interaction=0.017). In subgroup analyses, the association was stronger in individuals with a BMI <24 kg/m 2 , whereas no significant association was observed in those with a BMI ≥24 kg/m 2 . Descriptive findings also suggested that the association was stronger among males, older adults (≥55 years), individuals with hypertension, non-smokers, and those with HDL-C ≥1.04 mmol/L. Conclusions: Echocardiographic EAT thickness demonstrated a significant positive linear association with CAD, which was significantly modified by BMI, with a notably stronger effect observed in individuals with BMI <24 kg/m 2 . Routine echocardiographic assessment of EAT thickness may help identify individuals at higher CAD risk, particularly among those with a normal BMI.