Epicardial Adipose Tissue and Systemic Inflammation as Converging Signals of Subclinical Diastolic Dysfunction in Obesity

Objective: This study aimed to evaluate the association between epicardial adipose tissue (EAT) thickness, left ventricular diastolic dysfunction (LVDD), and hematological inflammatory indices—neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), systemic immune-inflammation index (SII), and systemic inflammatory response index (SIRI)—in obese individuals, to assess their discriminative performance for ASE/EACVI 2016–defined LVDD, and to interpret the findings within a subclinical phenotype consistent with obesity-related subclinical diastolic dysfunction (OSDDF). Methods: In this single-center cross-sectional study, 120 obese adults (BMI ≥30 kg/m²) and 110 normal-weight controls (BMI <25 kg/m²) were enrolled. NLR, PLR, SII, and SIRI were calculated from complete blood counts. EAT thickness was measured by transthoracic echocardiography, and LVDD was classified using the ASE/EACVI 2016 algorithm. Indeterminate cases were conservatively classified as LVDD-negative for binary analyses. The primary analysis focused on LVDD presence within the obese cohort. Correlation analyses, multivariable logistic regression, and ROC analyses were performed. Results: Obese participants had greater EAT thickness (6.2±1.1 vs 4.0±0.9 mm), higher E/e′ (9.8±2.1 vs 8.1±1.9), larger LAVI (31±6 vs 26±5 mL/m²), and higher LVDD prevalence (58.3% vs 20.9%) than controls (all p<0.001). NLR, PLR, SII, and SIRI were also increased in obesity (e.g., NLR 2.6±0.8 vs 1.9±0.6; SII 650±210 vs 470±180; p<0.001). Within the obese group, LVDD was associated with higher EAT, NLR, and SII (all p<0.001). EAT correlated positively with E/e′ (r=0.46), LAVI (r=0.41), NLR (r=0.38), and SII (r=0.42). EAT, NLR, and SII were independent predictors of LVDD. The combined EAT+NLR+SII model showed good discrimination (AUC 0.88). Conclusion: In obese adults, increased EAT thickness and systemic inflammatory burden—particularly NLR and SII—are independently associated with LVDD. Their combined assessment may provide a low-cost, accessible adjunct for identifying ASE/EACVI-defined subclinical diastolic dysfunction within an OSDDF-consistent phenotype.