Inherent suppression of thyroid stimulating hormone in newly diagnosed dyslipidemic patients - indication for use of thyromimetics?
BACKGROUND
Dyslipidemia triggers a sequel of metabolic derangements such as insulin resistance, hyperglycemia and oxidative stress via vicious cycle. Dyslipidemia is characterised by elevation of plasma cholesterol, triglycerides (TGs), or both, or a low level of high-density lipoprotein (HDL) which in turn can progress to atherosclerosis a forerunner for ischemic heart disease (IHD). Dyslipidemia is seen even in subclinical hypothyroid patients.


OBJECTIVE
The aim of the study was to look for thyroid & glycemic abnormalities in dyslipidemic patients and compare it with euthyroid, normolipidemic group.


METHODS
Thirty primarily dyslipidemic patients and 30 euthyroid normolipidemic subjects aged 25-55 years were tested for fasting plasma glucose (FPG), fructosamine, lipid profile, thyroid hormones - T3, T4 and thyroid stimulating hormone (TSH). The values were compared with those of age matched euthyroid normolipidemic control group.


RESULTS
The dyslipidemic pool showed small but significant decrease in the TSH levels with comparable T3, T4 levels as compared to euthyroid group. The group also had significantly higher FPG, total cholesterol (TC), triglycerides (TG), low density lipoprotein (LDL) levels and lower high density lipoprotein (HDL) levels as compared to the euthyroid normolipidemic group. The plasma fructosamine levels were similar in both the groups. The observed results reflected a picture of subclinical hyperthyroidism in dyslipidemic patients.


CONCLUSIONS
The observations of the present study preclude a need to assess the thyroid status in patients of primary dyslipidemia as both conditions per se have an increased risk of cardio vascular diseases. A subclinical hyperthyroid state may essentially be helpful in maintaining the lipid metabolism. The prevailing mild hyperthyroid status also makes it important to reconsider the accuracy of long term glycemic indicators like fructosamine and possibly glycated haemoglobin in these patients. Upon establishment of their efficacy and safety, thyromimetics may have a role in the treatment of dyslipidemia.
Assistant Professor, Department of Biochemistry, Subbiah Institute of Medical Sciences , Shimoga, India .
Sridevi V
SV
Udupa
Professor, Department of Biochemistry, Centre for Basic sciences, Kasturba Medical College , Mangalore, India .
Vivian
V
D'Souza
Assistant Professor, Department of Pathology, Subbiah Institute of Medical Sciences , Shimoga, India .
Vinit A
VA
Udupa
Professor and Head, Department of Biochemistry, Centre for Basic Sciences, Kasturba Medical College , Mangalore, India .
Poornima A
PA
Manjrekar
Dyslipidemia; Fructosamine; Lipid profile; Subclinical hyperthyroidism