European Journal of Cardiovascular Medicine

Diabetes mellitus has emerged as a major global health concern, with a rapidly rising prevalence in developing countries, including India. In addition to its well-recognized macrovascular and microvascular complications, diabetes exerts direct deleterious effects on the myocardium, a condition described as diabetic cardiomyopathy. This entity is characterized by myocardial structural and functional abnormalities occurring independently of coronary artery disease and hypertension, and often presents initially as left ventricular diastolic dysfunction.¹,²

Left ventricular diastolic dysfunction results from impaired myocardial relaxation and increased ventricular stiffness, leading to elevated left ventricular filling pressures. In its early stages, diastolic dysfunction is frequently asymptomatic and may remain clinically silent for prolonged periods. However, it represents an important pathophysiological substrate for the development of heart failure with preserved ejection fraction and is associated with adverse cardiovascular outcomes.³,⁴ Population-based studies have demonstrated that isolated diastolic dysfunction constitutes a significant proportion of subclinical cardiac dysfunction in the community and is linked to increased morbidity and mortality.⁵

Echocardiography is a widely available, non-invasive, and cost-effective modality for the evaluation of cardiac structure and function. Advances in Doppler and tissue Doppler imaging have substantially improved the assessment of left ventricular diastolic function. Current guidelines issued by the American Society of Echocardiography and the European Association of Cardiovascular Imaging recommend a multiparametric approach incorporating transmitral inflow velocities, mitral annular tissue velocities, left atrial volume index, and tricuspid regurgitation velocity for accurate diagnosis and grading of diastolic dysfunction.⁶

Several studies have reported a high prevalence of diastolic dysfunction among patients with type 2 diabetes mellitus, even in the absence of overt cardiovascular disease or systolic dysfunction.⁷,⁸ The reported prevalence varies across studies due to differences in patient demographics, duration of diabetes, glycaemic control, and echocardiographic criteria used. Indian studies have similarly demonstrated a substantial burden of diastolic dysfunction in patients with type 2 diabetes mellitus, highlighting the need for early cardiovascular evaluation in this population.⁹,¹⁰

Despite the high prevalence of diabetes in central India, data on echocardiographic assessment of diastolic dysfunction in diabetic patients from this region remain limited. The present study was therefore undertaken to evaluate left ventricular diastolic function in patients with type 2 diabetes mellitus using transthoracic echocardiography at a tertiary care centre in Nagpur, and to assess the prevalence and pattern of diastolic dysfunction in this population.

This hospital-based cross-sectional observational study was conducted in the Department of Medicine at Datta Meghe Medical College and Shalinitai Meghe Hospital and Research Centre, Wanadongri, District Nagpur, over a period of one year from October 2024 to September 2025. The study was conducted after obtaining approval from the Institutional Ethics Committee, and patient confidentiality was maintained throughout the study.

Adult patients aged 18 years and above with a confirmed diagnosis of type 2 diabetes mellitus according to the American Diabetes Association criteria, attending the outpatient department or admitted to the medicine wards during the study period, were screened for inclusion. Patients with a history of ischemic heart disease or prior myocardial infarction, moderate to severe valvular heart disease, atrial fibrillation or other significant arrhythmias, known cardiomyopathy or congenital heart disease, left ventricular systolic dysfunction with an ejection fraction less than 50%, advanced chronic kidney disease, or those with inadequate echocardiographic windows were excluded from the study. After explaining the study protocol, informed consent was obtained from all eligible participants prior to enrolment.

Detailed clinical and demographic data were collected using a structured proforma, including age, sex, duration of diabetes, treatment history, presence of associated comorbidities such as hypertension, and anthropometric measurements including height, weight, and body mass index. Blood pressure was measured using standard techniques. Laboratory investigations including glycated hemoglobin (HbA1c), fasting blood glucose, lipid profile, and serum creatinine were obtained either from hospital records or performed as part of routine clinical evaluation.

All enrolled patients underwent transthoracic echocardiographic evaluation using a standard echocardiography machine equipped with Doppler and tissue Doppler imaging. The examination was performed by an experienced cardiologist who was blinded to the clinical and laboratory details of the patients. Standard two-dimensional, M-mode, pulsed-wave Doppler, and tissue Doppler imaging were obtained in accordance with the recommendations of the American Society of Echocardiography. Left ventricular ejection fraction was calculated using the modified Simpson’s biplane method. Left ventricular diastolic function was assessed using mitral inflow parameters including peak early (E) and late (A) diastolic velocities and the E/A ratio, tissue Doppler-derived septal and lateral early diastolic velocities (e’), average E/e’ ratio, left atrial volume indexed to body surface area, and peak tricuspid regurgitation velocity where measurable. Diastolic dysfunction was diagnosed and graded into Grades I, II, and III using a multiparametric approach based on the 2016 recommendations of the American Society of Echocardiography and the European Association of Cardiovascular Imaging.

Data were entered into Microsoft Excel and analyzed using SPSS software version 20. Continuous variables were expressed as mean ± standard deviation, while categorical variables were expressed as frequencies and percentages. The chi-square test was used to assess associations between categorical variables, and the independent t-test was applied for comparison of continuous variables as appropriate. A p-value of less than 0.05 was considered statistically significant.

Table 1 shows that the baseline demographic and clinical characteristics were comparable between male and female patients. The mean age of males (55.0 ± 9.6 years) and females (54.0 ± 10.0 years) was similar, and there was no significant difference in the duration of diabetes between the two groups. Hypertension was present in nearly half of the study population, with a slightly higher prevalence among females (53.3%) compared to males (46.2%), though this difference was not statistically significant.

Female patients had a marginally higher mean body mass index than males (26.4 ± 3.6 vs 25.9 ± 3.2 kg/m²), while measures of glycaemic control, including HbA1c and fasting blood glucose levels, were comparable across genders. The prevalence of diastolic dysfunction was also similar in males (46.2%) and females (48.9%), with no significant gender-based difference observed. Overall, the table indicates that baseline characteristics were well balanced between male and female participants.

Table 1. Baseline demographic and clinical characteristics according to gender (n = 220)

Table 2 compares the clinical and laboratory parameters of patients with and without diastolic dysfunction. Patients with diastolic dysfunction were significantly older (58.3 ± 8.7 vs 52.0 ± 9.5 years) and had a longer duration of diabetes (9.2 ± 4.5 vs 6.2 ± 3.6 years) compared to those with normal diastolic function. Hypertension was also significantly more common in the diastolic dysfunction group (63.2% vs 38.4%). These patients had a significantly higher mean body mass index and poorer glycaemic control, as reflected by higher HbA1c levels.

In contrast, sex distribution did not differ significantly between the two groups. Fasting blood glucose levels were higher in patients with diastolic dysfunction, although the difference was not statistically significant. Lipid profile parameters, including total cholesterol, triglycerides, LDL and HDL cholesterol, were comparable between the two groups. Serum creatinine levels, smoking history, and family history of diabetes also did not show significant differences. Overall, the table indicates that age, duration of diabetes, hypertension, higher body mass index, and poor long-term glycaemic control were associated with diastolic dysfunction, while other metabolic and lifestyle variables were not significantly related.

Table 2. Comparison of clinical and laboratory parameters between patients with and without diastolic dysfunction (n = 220)

Grades of left ventricular diastolic dysfunction can be seen in table 3. More than half of the patients (56.8%) had normal diastolic function on echocardiographic evaluation. Among those with diastolic dysfunction, Grade I or impaired relaxation pattern was the most common finding, observed in 26.4% of patients. Grade II diastolic dysfunction was seen in 11.4% of patients, while Grade III or restrictive filling pattern was present in a smaller proportion (5.4%). Overall, the majority of patients with diastolic dysfunction had milder forms, with advanced grades observed in a relatively limited number of cases.

Table 3. Distribution of grades of left ventricular diastolic dysfunction (n = 220)

Echocardiographic assessment revealed that left ventricular systolic function was preserved in both groups, with a comparable mean ejection fraction in patients with diastolic dysfunction (59.8 ± 4.2%) and those with normal diastolic function (60.3 ± 3.8%), and this difference was not statistically significant (p = 0.35). In contrast, significant differences were observed in diastolic function parameters. Patients with diastolic dysfunction had markedly lower average mitral annular e′ velocities (6.2 ± 1.1 cm/s) compared to patients with normal diastolic function (8.4 ± 1.3 cm/s; p < 0.001). The average E/e′ ratio was significantly higher in the diastolic dysfunction group (15.6 ± 3.4) than in the normal group (9.8 ± 2.1; p < 0.001), indicating elevated left ventricular filling pressures. Additionally, the left atrial volume index was substantially increased among patients with diastolic dysfunction (38.2 ± 6.8 ml/m²) compared to those with normal diastolic function (28.6 ± 5.4 ml/m²; p < 0.001). These findings demonstrate that diastolic dysfunction in diabetic patients is associated with impaired myocardial relaxation and chronically elevated filling pressures despite preserved systolic function.

Table 4. Comparison of echocardiographic parameters between patients with and without diastolic dysfunction (n = 220)

Multivariate logistic regression analysis identified several independent predictors of left ventricular diastolic dysfunction. Increasing age was significantly associated with diastolic dysfunction, with the odds increasing by 6% for each additional year of age (adjusted OR 1.06; 95% CI 1.03–1.10; p < 0.001). A longer duration of diabetes also showed a strong independent association, with a 12% increase in odds of diastolic dysfunction for each additional year of disease duration (adjusted OR 1.12; 95% CI 1.06–1.18; p < 0.001). The presence of hypertension was associated with more than a two-fold higher risk of diastolic dysfunction (adjusted OR 2.14; 95% CI 1.22–3.74; p = 0.007). Poor glycaemic control, defined as HbA1c ≥8%, was also an independent predictor, increasing the likelihood of diastolic dysfunction by approximately 2.5 times (adjusted OR 2.48; 95% CI 1.41–4.36; p = 0.002). Additionally, higher body mass index was significantly associated with diastolic dysfunction, with an 8% increase in odds for each unit rise in BMI (adjusted OR 1.08; 95% CI 1.01–1.16; p = 0.03). These findings indicate that advancing age, longer diabetes duration, hypertension, poor glycaemic control, and increased BMI independently contribute to the development of diastolic dysfunction in patients with type 2 diabetes mellitus.

Table 5. Multivariate logistic regression analysis for predictors of diastolic dysfunction (n = 220)

In the present cross-sectional study, left ventricular diastolic dysfunction (LVDD) was detected in 43.2% of patients with type 2 diabetes mellitus despite preserved systolic function. The most frequent abnormality observed was Grade I diastolic dysfunction, indicating impaired myocardial relaxation. These findings support the concept that diabetic cardiomyopathy often manifests initially as subclinical diastolic dysfunction before the onset of overt heart failure.

The prevalence of LVDD observed in our cohort is comparable with several Indian studies conducted in different geographic regions. Sarkar et al. demonstrated a high prevalence of diastolic dysfunction among type 2 diabetic patients with normal systolic function, with significant correlations to duration of diabetes and poor glycaemic control [11]. Similar observations were reported by Ansari and Shaikh from Maharashtra, who noted that advancing age and longer disease duration were strongly associated with LVDD [12]. Kaushik et al. further highlighted that worsening grades of diastolic dysfunction were linked to microalbuminuria and prolonged diabetes, emphasizing the systemic nature of diabetic myocardial involvement [13].

In the present study, advancing age and longer duration of diabetes emerged as strong independent predictors of diastolic dysfunction. These findings are in agreement with Jain et al., who reported that even asymptomatic diabetic patients demonstrate progressive diastolic impairment with increasing age and disease duration [14]. Patel, Chauhan, and Amin also noted a rising prevalence of LVDD with longer duration of diabetes and worsening metabolic control, reinforcing the cumulative effect of chronic hyperglycaemia on myocardial structure and function [15].

Poor glycaemic control, reflected by elevated HbA1c levels, was independently associated with LVDD in our study. Pattnaik et al. reported a significant association between higher HbA1c levels and the presence as well as severity of diastolic dysfunction, suggesting that chronic hyperglycaemia contributes directly to myocardial stiffness and impaired relaxation [16]. Porel et al. further demonstrated that HbA1c could serve as a predictor of early diastolic dysfunction even in newly diagnosed normotensive diabetic patients, underscoring the importance of early metabolic control [17].

Hypertension was another significant determinant of LVDD in our cohort. The coexistence of diabetes and hypertension accelerates myocardial remodeling through pressure overload, interstitial fibrosis, and microvascular dysfunction. Similar associations have been reported by Metgudmath et al. and Mahesh et al., who observed higher rates of diastolic dysfunction among diabetic patients with concomitant hypertension [18,21]. Additionally, higher body mass index was independently associated with LVDD in the present study, consistent with prior reports linking obesity to increased ventricular stiffness and adverse myocardial remodeling [22].

From a mechanistic perspective, diabetic cardiomyopathy is driven by multiple interrelated pathways, including oxidative stress, accumulation of advanced glycation end products, altered myocardial energetics, and microvascular dysfunction. These changes impair calcium handling and myocardial relaxation, leading to elevated left ventricular filling pressures while systolic function remains preserved [8,10]. This pathophysiology is reflected in our echocardiographic findings of reduced mitral annular e′ velocities, increased E/e′ ratios, and enlarged left atrial volumes in patients with LVDD.

The clinical relevance of these findings lies in the silent nature of early diastolic dysfunction. Patients may remain asymptomatic for prolonged periods, yet are at increased risk of developing heart failure with preserved ejection fraction and other adverse cardiovascular outcomes. Routine echocardiographic screening in high-risk diabetic patients, particularly those with poor glycaemic control, longer disease duration, hypertension, and obesity, may therefore facilitate early detection and timely intervention [11–16].

While the present study provides valuable insight into the burden and determinants of diastolic dysfunction in diabetic patients from central India, certain limitations must be acknowledged. The cross-sectional design limits causal inference, and the single-centre setting may restrict generalizability. Advanced echocardiographic techniques such as myocardial strain imaging were not employed, which might have detected even earlier myocardial abnormalities.

Left ventricular diastolic dysfunction is a common echocardiographic abnormality among patients with type 2 diabetes mellitus, even in the presence of preserved systolic function. In the present study, nearly half of the diabetic patients demonstrated evidence of diastolic dysfunction, with impaired relaxation (Grade I) being the most frequently observed pattern. Advancing age, longer duration of diabetes, coexisting hypertension, poor glycaemic control, and higher body mass index were identified as independent predictors of diastolic dysfunction. These findings highlight the subclinical nature of diabetic cardiac involvement and underscore the importance of early cardiovascular evaluation in patients with type 2 diabetes mellitus. Routine echocardiographic assessment, particularly in high-risk individuals, may facilitate timely identification of diastolic dysfunction and allow for targeted interventions aimed at optimizing glycaemic control, managing blood pressure, and addressing modifiable risk factors. Early detection and appropriate management of diastolic dysfunction may help reduce progression to symptomatic heart failure and improve long-term cardiovascular outcomes in the diabetic population.

Funding: Nil.

Conflicts of interest: None

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