|Year : 2017 | Volume
| Issue : 1 | Page : 30-33
Prevalence of asymptomatic left ventricular diastolic dysfunction in type 2 diabetic patients and healthy controls: A comparative study
G Suresh1, Rhea Alva2, PS Prakash1, Rama Prakasha Saya2
1 Department of General Medicine, K. S. Hegde Medical Academy, Mangalore, Karnataka, India
2 Department of General Medicine, Kanachur Institute of Medical Sciences and Research Center, Mangalore, Karnataka, India
|Date of Web Publication||16-Jun-2017|
Rama Prakasha Saya
Department General Medicine, Kanachur Institute of Medical Sciences and Research Center, Natekal, Mangalore - 575 018, Karnataka
Source of Support: None, Conflict of Interest: None
Background and Objective: Type 2 diabetes increases the risk of heart failure independently of other risks factors such as coronary artery disease and hypertension. The objective of the study is to assess the prevalence of asymptomatic left ventricular diastolic dysfunction in patients with type 2 diabetic and in healthy controls. Materials and Methods: This is a cross-sectional comparative study conducted over a period of 1½ years. The study group included 50 diabetics and 50 healthy controls recruited from both in- and out-patient departments; age- and sex-matched. The analysis was done using proportions, Z test to see the difference in prevalence between two groups, odd's ratio to assess the risk and Chi-square test to see the statistical significance. Results: Diastolic dysfunction was found in 36 (72%) of the diabetic patients and in 15 (30%) of the healthy controls. Odds ratio was 6, indicating a 6 times higher risk of developing diastolic dysfunction among diabetic patients compared to the healthy controls. The prevalence of diastolic dysfunction showed no significant difference among the gender and age in both groups. Diastolic dysfunction was more prevalent in diabetic patients with fasting blood glucose value greater than 167 mg/dL and postprandial blood glucose value more than 199 mg/dL; with a sensitivity of 72.2% and specificity of 64.3%. Furthermore, glycated hemoglobin (HbA1c) value greater than 8.1% showed increased the prevalence of diastolic dysfunction in diabetic patients with a sensitivity of 80.6% and specificity of 71.4%. Conclusion: There was a significantly higher prevalence of diastolic dysfunction in diabetic patients with 6 times higher risk of developing diastolic dysfunction as compared to the healthy controls. Both fasting and postprandial blood sugars, as well as HbA1c, were found to be good indicators of diastolic dysfunction in diabetic patients.
Keywords: Diabetes mellitus, diastolic dysfunction, heart failure, prevalence
|How to cite this article:|
Suresh G, Alva R, Prakash P S, Saya RP. Prevalence of asymptomatic left ventricular diastolic dysfunction in type 2 diabetic patients and healthy controls: A comparative study. Arch Med Health Sci 2017;5:30-3
|How to cite this URL:|
Suresh G, Alva R, Prakash P S, Saya RP. Prevalence of asymptomatic left ventricular diastolic dysfunction in type 2 diabetic patients and healthy controls: A comparative study. Arch Med Health Sci [serial online] 2017 [cited 2020 Aug 6];5:30-3. Available from: http://www.amhsjournal.org/text.asp?2017/5/1/30/208211
| Introduction|| |
Several epidemiologic studies reported the frequent coexistence of type 2 diabetes mellitus and heart failure (HF). Furthermore, it has been proved that type 2 diabetes increases the risk of HF independently of other risks factors such as coronary artery disease (CAD) and hypertension.,, Dilated cardiomyopathy has been attributed as an important cause of HF in diabetic patients. Left ventricular diastolic dysfunction (LVDD) represents the first stage of dilated cardiomyopathy in diabetic patients. Hence, the early identification of type 2 diabetes patients with asymptomatic LVDD might have relevant clinical, prognostic, and economic implications for preventing or delaying the evolution of overt HF.
With this in the background, the study is done to assess the prevalence of asymptomatic LVDD in subjects with type 2 diabetes and to compare it with the healthy controls.
| Materials and Methods|| |
This cross-sectional comparative study was done in a tertiary care hospital in south India. The study duration was from January 2014 to June 2015. The institutional ethical clearance was obtained before the study. Sample sizes were 50 patients with a confirmed diagnosis of type 2 diabetes mellitus and 50 age- and sex-matched controls. Both groups were normotensive and included patients with blood pressure of <140/90 mm of Hg. Study subjects were recruited from both in- and out-patient departments, and were age- and sex-matched.
The inclusion criteria were normotensive subjects (blood pressure <140/90) aged >30 years, with normal ejection fraction, and with a diagnosis of type 2 diabetes mellitus based on current criteria of the American Diabetes Association, 2010. Those patients with any overt symptoms of HF such as dyspnea and edema were excluded from the study. Those patients with history, investigation findings or a documented evidence of ischemic heart disease were excluded from the study. The study also excluded subjects with valvular and congenital heart disease and congestive HF of any cause. Control group included 50 apparently healthy age- and sex-matched controls.
LV diastolic dysfunction is defined as (1) an inability to fill the left ventricle, during rest or exercise, to a normal end-diastolic volume without an abnormal increase in LV end diastole or mean left atrial pressure; or (2) failure to increase LV end diastolic volume and therefore cardiac output during exercise. The diagnosis of diabetes was based on current criteria of the American Diabetes Association, 2010 (Random blood glucose concentration >200 mg/dL or Fasting plasma glucose >126 mg/dL or 2-h plasma glucose >200 mg/dL). Glycated hemoglobin (HbA1c) was estimated by direct enzymatic HbA1c assay (DiaSys, Holzheim, Germany). HbA1c of <6% was defined as nondiabetic level, and 6%–7% as near normal glycemia in our laboratory.
Statistical analysis was done using proportions and Z test to see the difference in prevalence of two groups. Odd's ratio, Chi-square test, and receiver operating characteristic (ROC) analysis tests were performed. P < 0.05 was considered statistically significant.
| Results|| |
The baseline study characteristics of cases (50) and controls (50) are given in [Table 1]. About half (52%) of the cases and controls were between the age group of 40 and 60 years. Among 50 diabetic patients, 16 were on oral hypoglycemic agents, 6 were on insulin, and 28 were on insulin and oral hypoglycemic agents. None of the patients were on angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers, and 23 cases were using statins. The mean diabetes duration was 5.64 ± 4.28 years in this study. Among 50 cases, 36 had diastolic dysfunction. Of the 50 controls, 15 patients had diastolic dysfunction. There was a significantly higher prevalence of diastolic dysfunction among diabetics as compared to healthy controls (χ2 =17.647; P ≤ 0.001). The prevalence of diastolic dysfunction among the different age groups of cases and controls is shown in [Table 2].
Diastolic dysfunction was present in 68.18% of diabetic males and in 75% of diabetic females (P = 0.753). Among the healthy controls, 33% of females and 34.61% of males had diastolic dysfunction (P = 0.459). Among the cases, 41.7% subjects had Grade I, 36.1% subjects had Grade II and 22.2% subjects had Grade III diastolic dysfunction. Among the controls, 46.7% subjects had Grade I, 33.3% subjects had Grade II, and 20% subjects had Grade III diastolic dysfunction [Figure 1].
Mean fasting blood glucose (FBS) value of diabetic patients with and without diastolic dysfunction were 197.33 mg/dL and 155.21 mg/dL respectively (P = 0.007, highly significant). Mean postprandial blood sugar (PPBS) value of diabetic patients with and without diastolic dysfunction were 245.03 mg/dL and 193.00 mg/dL respectively (P = 0.006, highly significant). Mean HbA1c value of diabetic patients with and without diastolic dysfunction were 10.21 and 7.81, respectively (P < 0.001, highly significant) [Table 3].
|Table 3: Correlation of fasting blood sugar, postprandial blood sugar, and glycosylated hemoglobin with diastolic dysfunction|
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Receiver operator characteristic curve is plotted with the FBS, PPBS, HbA1c variables to calculate the sensitivity and specificity of this test for the detection of diastolic dysfunction. P value for the area under the ROC curve is statistically significant (P < 0.001). From the coordinates of ROC curve plotted, diastolic dysfunction was more prevalent in diabetic patients with FBS value greater than 167 mg/dL, with a sensitivity of 72.2% and specificity of 64.3%; PPBS value greater than 199 mg/dL, with a sensitivity of 72.2% and specificity of 64.3% and HbA1c value greater than 8.1%, with a sensitivity of 80.6% and specificity of 71.4% [Figure 2].
| Discussion|| |
Myocardial damage in patients with diabetes affects diastolic function before systolic function., Diastolic dysfunction may be the earliest marker of diabetes-induced dilated cardiomyopathy, which leads to the progressive development of HF. In diabetes, along with increased collagen deposition, there is also an increase in the cross-linking of collagen fibers which contributes to a reduction in ventricular compliance., Apart from diabetes, diastolic dysfunction may also be seen in patients with ischemic heart disease, systemic hypertension, cardiomyopathy, and valvular heart diseases. Hence, in this study, patients with the above conditions were excluded. None of these subjects had clinical symptoms suggestive of overt cardiac disease. Clinical examination, electrocardiography as well as X-ray chest were normal. In this study, odds ratio was 6, indicating a 6 times higher risk of developing diastolic dysfunction among cases compared to the control group subjects (95% confidence interval: 2.528–14.240).
Age is a known indicator in impaired diastolic function. However, in this study, the prevalence of diastolic dysfunction among the age groups and gender did not show any significant difference in both groups. Grades of diastolic dysfunction also showed no relation to age and gender.
Kahn et al. detected abnormalities of LV diastolic function by radionuclide ventriculography in young asymptomatic diabetic patients, free of clinical heart disease. Of the 28 diabetic patients studied, 21% had abnormal diastolic filling as judged by abnormally low peak filling rates or prolonged time to peak filling, compared with healthy controls. Cioffi et al. conducted a study on 960 diabetic patients without overt cardiac disease from 2006 to 2008 and found asymptomatic diastolic dysfunction in 66.5% of diabetics. Faden et al. conducted a study on 386 diabetic patients without overt cardiac disease and showed asymptomatic LV dysfunction in 262 patients (68%). Another study by Poirier et al. showed LVDD in 28 subjects (60%) of 46 men with type 2 diabetes who were aged 38–67 years; without evidence of diabetic complications, hypertension, CAD, congestive HF, or thyroid or overt renal disease.
In this study, diastolic dysfunction was more prevalent in diabetic patients with FBS and PPBS value greater than 167 mg/dL and 199 mg/dL, respectively. Furthermore, diastolic dysfunction was more prevalent in diabetic patients with HbA1c value greater than 8.1%. Studies by Cioffi et al. and Liu et al. indicated HbA1c as a predictor of the occurrence of diastolic dysfunction in diabetics., This study also shows that FBS, PPBS, and HbA1c can be used to assess the prevalence of diastolic dysfunction in diabetics. Further evaluation of the significance of these parameters in prevalence and prognosis of diastolic dysfunction in diabetic patients is needed. This may help us identify the diabetic patients at risk of developing diastolic dysfunction and eventually HF. Diastolic dysfunction if left untreated can progress to clinically significant HF. Hence, early detection of asymptomatic diastolic dysfunction will allow us to start early treatment for the same and arrest the progression of diastolic dysfunction. Doppler echocardiography is a reliable noninvasive means to assess early diastolic dysfunction of the left ventricle. It identifies diastolic dysfunction of the left ventricle before abnormalities are detected clinically or by electrocardiogram.
The assessment of LV diastolic filling in adults of the American Indian Communities with Type 2 diabetes mellitus in a population-based sample of middle-aged and older adults by Liu et al., revealed that diabetic patients with abnormal LV diastolic filling had worse glycemic control as indicated by higher levels of hemoglobin A1C and fasting glucose than diabetic patients with normal LV diastolic filling. Suggesting that, diabetes mellitus, especially with worse glycemic control, is independently associated with abnormal LV relaxation. A case–control study by Patil et al., conducted at a tertiary care hospital in Karad, from January 2009 to December 2009, showed 69 (54.33%) of the total 127 cases had diastolic dysfunction, and 11% among 100 in the control group population showed diastolic dysfunction. Patients with a longer duration of diabetes (of 11–15 years) had a higher prevalence of diastolic dysfunction. Subjects with HbA1c >7.5% had a higher prevalence of diastolic dysfunction than subjects with HbA1c <7.5%. At the end, the therapeutic management of diastolic HF is, at least partially, empirical and several studies, ongoing or completed, have been planned to test the effects of ACE inhibitors, angiotensin inhibitors, and β-blockers.
The present study had potential limitations, including a small sample size, lack of randomization, and the lack of detailed evaluation of other causes of HF like thyroid function tests. Furthermore, the study population includes patients from the selected region only. Coronary angiogram was not done to rule out CAD, and this may lead inclusion of subclinical or undiagnosed CAD cases. Cutoff value for HbA1c for diabetes was >7% in this study, and thus, a significant proportion with undiagnosed pre-diabetes might have been included in the control group, which may alter the results.
| Conclusion|| |
This study found a significantly higher prevalence of diastolic dysfunction in diabetic patients with a 6 times higher risk of developing diastolic dysfunction as compared to the healthy controls. No correlation between age and gender with diastolic dysfunction was noted in the study. FBS, PPBS, and HbA1c were found to be good indicators of diastolic dysfunction.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3]