The Effect of Thyroid Hormone Replacement on the Level of Blood Pressure in the Cases of Subclinical Hypothyroidism

Background: Hypothyroidism (both subclinical and overt) is associated with increased cardiovascular morbidity. About 3% hypertensive patients found to have hypothyroidism during the routine investigations. Objectives: To assess the effect of thyroid hormone replacement on the level of blood pressure in the cases of newly diagnosed subclinical hypothyroidism. Methods: Patients above the age of 15 years admitted to various wards (Indoor) or attending Endocrinology OPD at teriatary care health centre of north India were enrolled during the period of one year. The cases were divided into two groups, normotensive and hypertensive. Cases with subclinical hypothyroidism after evaluation were prescribed thyroxine replacement therapy to achieve euthyroid function. Each group followed periodically at 1 ½, 03 and 06 month with measurement of blood pressure and serum TSH, T3 and T4 level. Results: The prevalence of hypertension in cases of subclinical hypothyroidism in this study was 33.4 per 100 populations. There was no correlation between serum TSH level and blood pressure level in hypertensive group (p>0.05). In hypertensive group mean fall in blood pressure after thyroxine replacement therapy was systolic blood pressure 20.10±11.2 diastolic blood pressure 13.16±3.8 and in mean arterial pressure 15.2±4.7. With replacement of thyroxine hormone, the blood pressure was normalized in 47.4% (45 out of 95 cases) cases with elevated blood pressure. Conclusion: The effect of thyroxine replacement therapy in cases of hypertension with subclinical hypothyroidism on blood pressure was significant reduction in blood pressure after achieving normal thyroid function.