PREVALENCE OF HYPOTHYROIDISM IN TYPE 2 DIABETES MELLITUS

Introduction : Thyroid hormone deficiency can lead to adverse health effects even death, if left untreated. It is a pathological condition known as hypothyroidism. Most common symptoms of hypothyroidism in adults are weight gain, fatigue, lethargy, cold intolerance, constipation, and dry skin. These clinical presentations can differ with age and sex, among other factors. Thyroid Stimulating Hormone (TSH), is associated with an increased risk of developing a number of clinical conditions, like cardiovascular diseases, diabetes, lung disease, malignant condition, and psychiatric disorders, both before and after the diagnosis of thyroid dysfunction. Type 2 Diabetes Mellitus (T2DM) is the chronic endocrine disease which is characterized by hyperglycemia resulting in impaired insulin secretion insulin resistance. Material and Methods : This prospective observational study was carried out at OPD of Dept. of Medicine at Govt. Doon Medical College and Hospital. The study period was between jan2019 to August 2019. The anthropometric measurements and demographic characteristics of patients included in the study were recorded. The clinical details and medications are entered into Excel sheet of Microsoft Excel 2013. Biochemical tests were done and reports were entered. Results : Prevalence of hypothyroidism in T2DM is found to be 10.94% in our study. Average BMI was observed to be 28.01 kg/m 2 with SD of 3.39 kg/m 2 . Level of T3 and T4 were observed to be 0.98(0.23) ng/ml and 1.24(0.29) ng/ml respectively. Fasting blood glucose level was 133.05(17.81) mg/dl and post prandial blood glucose level was 201.54(27.33) mg/dl. Among all 112 patients, 71(63.39%) of cases had a family history of diabetes. Conclusion : It is noted that one-tenth of patients with type 2 diabetes mellitus has hypothyroidism. BMI was noted to be more than 28 kg/m 2 among all patients. Hypothyroidism may be prevalent in T2DM patients due to duration of diabetes, obesity. To confirm the findings, more studies in this area are required.


Introduction:
Thyroid hormone deficiency is a pathological condition known as hypothyroidism, which can lead to adverse health effects even death, if left untreated. Definition of hypothyroidism is predominantly biochemical due to absence of specific symptom and variation in clinical presentation. A clinical manifestation of thyroid hormone deficiency ranges from life threatening to no symptoms or signs. Most common symptoms of hypothyroidism in adults are weight gain, fatigue, lethargy, cold intolerance, constipation, and dry skin. These clinical presentations can differ with age and sex, among other factors i . The thyroid hormones thyroxine (T 4 ) and triiodothyronine (T 3 ) are essential in the regulation of a number of vital pathways like lipolysis, gluconeogenesis and oxidative phosphorylation ii . Prevalence of hypothyroidism in India is about 11% iii .
Thyroid Stimulating Hormone (TSH), is associated with an increased risk of developing a number of clinical conditions, like cardiovascular diseases, diabetes, lung disease, malignant condition, and psychiatric disorders, both before and after the diagnosis of thyroid dysfunction. Whether this increased burden of morbidity also manifests as increased mortality in patients with thyroid dysfunction is controversial iv , v .there is chronic association of Diabetes and hypothyroidism. Both the diseases have chronic effects on cardiovascular system and increased mortality vi . Type 2 Diabetes Mellitus (T2DM) is the chronic endocrine disease which is characterized by hyperglycemia resulting in impaired insulin secretion insulin resistance vii . Due to increases prevalence of obesity, diabetes is also increasing. The global prevalence is estimated to be 11.1% in 2033, affecting 600 million people viii . In India diabetes is estimated to affect about 6.5% to 19.5% of adult Indians. ix Subclinical hypothyroidism sometimes is associated with higher risk of heart failure and stroke in the young adult population 1 . Also there is higher prevalence of subclinical hypothyroidism in patients with type 2 diabetes mellitus and higher prevalence of microvascular complications in the patients having both the conditions x . According to various studies the prevalence of hypothyroidism among patients with diabetes is reported from 4.8 to 31.4% xi .
This study was conducted with an aim to find the prevalence of hypothyroidism among T2DM.

MATERIALS AND METHODS:
This prospective observational study was carried out at OPD of Dept. of Medicine at Govt. Doon Medical College and Hospital Dehradun. The study period was between January 2019 to August 2019. The anthropometric measurements and demographic characteristics of patients included in the study were recorded. The clinical details and medications are entered into Excel sheet of Microsoft Excel 2013. Biochemical tests were done and reports were entered.
Patients included were diagnosed T2DM cases attending OPD of Medicine department. TSH test was done on all patients. History of diabetes (in years), family history of diabetes, blood pressure, pulse rate was recorded. History of smoking, alcoholism, drug abuse was noted. HbA1c, fasting blood glucose level tests were carried out.BMI of each patient was calculated.
Patients were labeled as hyperthyroid if they have been or are on antithyroid medications or have a TSH <0.5 μIU/ml.

RESULTS
A total of 1023 T2DM patients who attended Medicine OPD in study period were screened for hypothyroidism among which 112 were diagnosed as hypothyroidism and were included in the study.  In present study the mean (SD) age of cases was found to be 48.31(4.22) years. Average BMI was observed to be 28.01 kg/m 2 with SD of 3.39 kg/m 2 . Level of T3 and T4 were observed to be 0.98(0.23) ng/ml and 1.24(0.29) ng/ml respectively. Mean(SD) of TSH levels was 12.21(3.99)μIU/ml. Total Serum cholesterol levels were found to be 208.11 mg/dl on average with SD of 21.32mg/dl. Hb1Ac count is seen as 10.23(2.57) on average. Fasting blood glucose level was 133.05(17.81) mg/dl and post prandial blood glucose level was 201.54(27.33) mg/dl.  There is prolonged peripheral glucose accumulation, gluconeogenesis, diminished hepatic glucose output due to reduced glucose absorption from gastrointestinal tract xv . Insulin resistance leads to glucose stimulated insulin secretion in cases of overt or subclinical hypothyroidism xvi . There is diminished rate of insulin stimulated glucose transport rate caused by perturbed expression of glucose transporter type 2 gene (GLUT 2) translocation in subclinical hypothyroid cases. Anorectic conditions in hypothyroidism may also contribute to reduced insulin xvii .
In our study average years with diagnosed T2DM was 3.7 years on average with SD of 2.25 years. Among all 112 patients, 71(63.39%) of cases had a family history of diabetes. In a study by Nair A. noted that there was an association between duration of diabetes and hypothyroidism, which suggested contribution cumulative effect if hyperglycemia 13 .

CONCLUSION:
It is noted that one among 10 patients with type 2 diabetes mellitus has hypothyroidism. BMI was noted to be more than 28 kg/m 2 among all patients. Hypothyroidism may be prevalent in T2DM patients due to duration of diabetes, obesity. More studies in this area are required to confirm the findings.