A Study on Diastolic Dysfunction in Asymptomatic Type 2 Diabetes Mellitus with Normal Systolic Function

INTRODUCTION: The incidence of diabetes mellitus (DM) is on the raise across the world and it is turning out to be an epidemic of non communicable disease. Diabetic heart disease and Diabetic Cardiomyopathy as a separate entity has been proposed in the last couple of decades. Diastolic heart failure, otherwise called as heart failure with preserved ejection fraction, is common finding of hypertensive heart disease, but various studies report a high incidence of diastolic heart failure in patients with type 2 diabetes mellitus inspite of the absence of coronary artery heart disease and hypertension. AIM AND OBJECTIVES: 1. To determine the incidence of LV diastolic dysfunction in asymptomatic type 2 DM patients and to compare it with normal subjects. 2. To quantify the relation of LV diastolic dysfunction with age, duration of DM, obesity indices and other diabetic complications such as microangiopathies. MATERIALS AND METHODS: Settings and Design: This will be case control prospective study conducted at the tertiary care hospital during a one year period. Period of study: One year. Sample size: 50. Inclusion Criteria: All type 2 DM with patients with duration > 5 years with normal left ventricular systolic function (LVEF: ≥ 50%). Exclusion Criteria: 1. Subjects with evidence of coronary artery disease - CAD (excluded by history of angina, chest pain, Electrocardiogram (ECG) changes and abnormal Treadmill test (TMT) results). 2. Subjects with evidence of valvular disease. 3. Hypertensive patients on antihypertensive agents and/ or angiotensin-converting enzyme (ACE) inhibitors, with evidence of left ventricular hypertrophy on echocardiography. 4. Subjects with poor transthoracic echo window. METHOD OF STUDY: Detailed medical history was collected from each eligible subject; and, they underwent physical examination and biochemical investigations. Biochemical investigations of fasting sugar, lipid profile, HbA1C, anthropometric examination of waist hip ratio, height, weight and BMI were calculated. Echocardiogram was done to find out diastolic dysfucntiom. Diagnostic criteria: 1. Dyslipidemia: defined if TC ≥ 200 mg/dL; LDL cholesterol ≥ 130 mg/dL; HDL cholesterol 40 mg/dL; and, TG ≥ 150 mg/dL. 2. Obesity indices: Cut-off for high Body Mass Index (BMI) ≥ 25 for females and ≥ 27 for males. Cutoff for high waist to hip ratio (WHR) ≥ 0.9 for males, and ≥ 0.8 for females. Cut-off for high WC > 85 cm for females and > 90 cm for males. 3. Diabetes mellitus (DM): If a subject is a known diabetic on treatment, or with any fasting blood sugar level (F-BSL) ≥ 126 mg/dL. 4. Retinopathy: Microangiopathy to be assessed by fundoscopy (direct ophthalmoscopy). The ophthalmologist doing fundoscopy will be unaware of this study. Fundoscopic examination to be done after dilating the pupil with tropicamide (1%). Retinopathy status will be labeled as follow: a) no evidence of diabetic retinopathy, b) preproliferative diabetic retinopathy, c) proliferative diabetic retinopathy. 5. Diastolic dysfunction is labelled according to the standard guidelines. Diastolic dysfunction: LV diastolic dysfunction is considered to be present if any of the following findings is seen, • E/A ratio 2 • DT 220 ms, • IVRT 100 ms, or • E/e’ ratio > 15. RESULTS: Of the total 50 patients in the cases arm 30 had diastolic dysfunction which is 60% prevalence. On the control arm a total of 7 had diastolic dysfunction which equals to 14%. A total of 13 patients were of age 45 years. A total of 23 patients in this category had diastolic dysfunction which equals 62.16%.31 patients in cases arm had HBA1c less than 7.5 gm% and 19 had HBA1c greater than7.5gm%. 14 patients with HBA1c less than 7.5gm% had diastolic dysfunction with a prevalence of 45.2%. 16 patients with HBA1c greater than 7.5 gm% had diastolic dysfunction with a prevalence of 84.2%.38 patients had diabetes mellitus for 6-10 years and 12 had duration between11-15 years. 22 patients with duration 6-10 years had diastolic dysfunction with a prevalence of 57.9%. 8 patients with duration of diabetes 11-15 years had diastolic dysfunction with a prevalence of 66.67%. A total of 12 patients had diabetic retinopathy while the remaining 38 did not show features of diabetic retinopathy. Of the 12 patients 9 had diastolic dysfunction with a prevalence of 75%. A total of 12 patients had autonomic dysfunction and remaining 38 patients did not have autonomic dysfunction. Of the 12 patients with autonomic dysfunction 9 had diastolic dysfunction with an incidence of 75%. The incidence of diastolic dysfunction is more in age > 45 years with the Statistical ‘p’ value of 7.5 gm% with a statistical ‘p’ value of < 0.02. The incidence of diastolic dysfunction occurs more often after a 5 years duration with an incidence in 6-10 years of 73.33% of total and a stastical ‘p’ value of < 0.02. The incidence of diastolic dysfunction 75 % when the patient develops diabetic retinopathy. The incidence of diastolic dysfunction 75% when the patient develops diabetic autonomic neuropathy. CONCLUSION: Diabetes Mellitus causes serious morbidities one of which is cardiovascular. The occurrence of coronary artery disease and systolic dysfunction are well known. However the prevalence of a diastolic dysfunction even in asymptomatic patients independent of a CAD is a relatively new observation. It is also obvious that, diastolic dysfunction correlates well with diabetes duration, micro vascular abnormalities obesity index, lipid profile and HbA1c. Diastolic dysfunction, being a marker of Diabetic Cardiomyopathy, may be useful as the predictor of heart failure with preserved ejection fraction and mortality in the medium to long ter