Association between Non-Alcoholic Fatty Liver Disease and Left Ventricular Diastolic Dysfunction in Patients with Type 2 Diabetes Mellitus: A Hospital-Based Case-Control Study

Background: Non-alcoholic fatty liver disease (NAFLD) is currently recognized as the hepatic manifestation of metabolic syndrome and is highly prevalent among patients with type 2 diabetes mellitus (T2DM). Besides progressive liver injury, NAFLD has emerged as an important predictor of cardiovascular morbidity and mortality. Increasing evidence suggests that NAFLD is associated with subclinical cardiac dysfunction, particularly left ventricular diastolic dysfunction (LVDD), even in the absence of overt cardiovascular disease. However, studies evaluating this association in the Indian population remain limited. Early identification of cardiac dysfunction among diabetic patients with NAFLD may facilitate timely intervention and reduce future cardiovascular complications. Objective: To evaluate the association between non-alcoholic fatty liver disease and left ventricular diastolic dysfunction in patients with type 2 diabetes mellitus. Secondary Objectives: 1. To determine the prevalence of left ventricular diastolic dysfunction among patients with type 2 diabetes mellitus having NAFLD. 2. To identify early echocardiographic abnormalities in diabetic patients with NAFLD. 3. To compare echocardiographic parameters between diabetic patients with and without NAFLD. 4. To assess the clinical significance of NAFLD as a predictor of subclinical cardiac dysfunction. Materials and Methods: A hospital-based case-control study was conducted in the Department of General Medicine, SMS Medical College and Hospital, Jaipur, Rajasthan, between January 2023 and June 2024. A total of 100 patients with type 2 diabetes mellitus were enrolled, comprising 50 patients with ultrasonographically diagnosed NAFLD (cases) and 50 diabetic patients without NAFLD (controls). Eligible participants underwent detailed clinical evaluation, laboratory investigations, abdominal ultrasonography, and comprehensive transthoracic echocardiography with tissue Doppler imaging for assessment of left ventricular systolic and diastolic function. Patients with ischemic heart disease, significant valvular heart disease, chronic liver disease of other etiologies, alcohol use, severe renal dysfunction, autoimmune diseases, or malignancy were excluded. Statistical analysis was performed using appropriate parametric and non-parametric tests. Continuous variables were expressed as mean ± standard deviation, while categorical variables were expressed as frequencies and percentages. Comparisons between groups were performed using the unpaired Student's t-test and Chi-square test. Logistic regression analysis was used to evaluate independent predictors of diastolic dysfunction. A p-value <0.05 was considered statistically significant. Results: The mean age of study participants was 55.47 ± 8.62 years, with no statistically significant difference between the case and control groups. Baseline demographic characteristics including age, sex distribution, smoking status, hypertension, and statin use were comparable between both groups, minimizing confounding influences. Patients with NAFLD demonstrated a significantly higher prevalence of left ventricular diastolic dysfunction compared with diabetic patients without NAFLD. Tissue Doppler echocardiographic parameters indicative of impaired ventricular relaxation were significantly altered among patients with NAFLD despite preserved left ventricular systolic function. The findings suggest that NAFLD is independently associated with early myocardial dysfunction in patients with type 2 diabetes mellitus. Conclusion: Non-alcoholic fatty liver disease is strongly associated with subclinical left ventricular diastolic dysfunction in patients with type 2 diabetes mellitus, independent of conventional cardiovascular risk factors. Routine screening for NAFLD and early echocardiographic assessment of cardiac function in diabetic patients may facilitate earlier diagnosis of diabetic cardiomyopathy and improve cardiovascular risk stratification. Early recognition and comprehensive management of NAFLD may contribute to reducing cardiovascular morbidity and improving long-term clinical outcomes in patients with type 2 diabetes mellitus.