Effects of thyroid function on blood pressure. Recognition of hypothyroid hypertension.

Abstract

SUMMARY Hypothyroid ism has been known to be associated, at times, with diastolic hypertension. We have found in 40 thyrotoxic patients that the induction of hypothyroid ism by radioiodine therapy significantly increased diastolic blood pressure, raising it above 90 mm Hg in 16 (40%) of the patients. Restoration of euthyroidism with thyroxine administration significantly reduced the systolic and diastolic blood pressures in these patients, with a fall in diastolic pressure below 90 mm Hg in nine of 16 patients. The prevalence of hypothyroid ism was determined by measurements of serum thyroxine and thyrotropin concentrations in 688 consecutive hypertensive patients, referred for evaluation and therapy of their hypertension. Hypothyroidism was found in 25 (3.6%) of the patients. Restoration of normal serum thyroxine and thyrotropin levels with thyroid hormone replacement therapy lowered diastolic blood pressure to levels below 90 mm Hg in 32% of these patients who could be followed up after withdrawal of all antihypertensive drug therapy when euthyroidism had been restored (i.e., 1.2% of the 688 patients). It is concluded that diastolic hypertension resulting from hypothyroidism is a relatively common disorder, present in 1.2% of our referred hypertensive patients, that should be sought and treated. (Hypertension 11: 78-83, 1988) KEY WORDS • hypothyroid hypertension • endocrine hypertension • thyroid in hypertension H YPERTHYROIDISM is usually associated with peripheral vasodilatation and reduction of the diastolic blood pressure (BP) and sometimes with systolic hypertension, while hypothyroidism may be accompanied by diastolic hypertension, as many clinicians are aware. Elevation of the diastolic BP was found to be common in patients with hypothyroidism 1 and has been reported in small groups of patients with hypothyroidism and myxedema by several investigators, 2 " 6 who have all found a fall in diastolic BP when the hypothyroidism was corrected with thyroid replacement therapy. The latter observations were preceded by a report that desiccated thyroid administration lowered the BP to normal levels in 14% of 334 patients with essential hypertension, at a time (in 1950) when virtually no effective forms of antihypertensive therapy were available. Received February 11, 1987; accepted August 13, 1987. were reported by Fuller et al. 2 However, in a comparison of BP measurements in 80 hypothyroid patients and 73 euthyroid subjects, Endo et al. 8 found no evidence that hypothyroidism predisposed to hypertension. Apart from this negative study, there have been no recent attempts to determine the frequency with which hypertension may be associated with and caused by hypothyroidism, the treatment of which will restore the BP to normal. We have sought to obtain this information 1) by studying the BP responses of a series of patients with thyrotoxicosis to therapy with radioiodine as they became euthyroid and, frequently, hypothyroid and during correction of the iatrogenic hypothyroidism with thyroxine therapy and 2) ...

The lack of association between hypertension and hypothyroidism in a primary care setting

“…Our findings are in concordance with previous work studying non-referred individuals 13,14 but contrast with reports from specialty clinics. [2][3][4][5][6] In our earlier cross-sectional study of post-menopausal women at a primary care office no association between hypothyroidism and hypertension was detected. 14 The second negative study was community-based and compared 81 hypothyroid women to 73 euthyroid women drawn from the surrounding community.…”

“…TSH was forced to remain within the regression model became hypothyroid following treatment with radioiodine. 3 Sixteen (40%) of these patients also developed hypertension but after receiving thyroid replacement nine of the 16 (56%) returned to a normotensive condition. These studies lacked control groups and it is possible that some of the individuals were demonstrating a placebo effect.…”

“…Streeten reported a case series of 25 patients, with a mean age of 49.8 years, referred to a specialty clinic for evaluation and treatment of hypertension who were found to be hypothyroid. 3 Following thyroid replacement therapy, 32% of the patients with hypothyroidism became normotensive. He reported that the responders tended to be younger than non-responders.…”

“…Several researchers have reported finding an association between hypothyroidism and hypertension, but these reports are largely based on referred middle-aged subjects. [2][3][4][5][6][7] While hypothyroidism is identified as a cause of diastolic hypertension in many medical textbooks [8][9][10][11] and in review articles 1,12 research based on non-referred subjects is contradictory about the association. [13][14][15] Hypothyroidism and diastolic hypertension are both common and have prevalences which increase with age.…”

Blood pressure in relation to serum thyrotropin: the Tromsø study

“…Thus, in a study by Streeten et al 20 on 688 hypertensive subjects the prevalence of hypothyroidism was 3.6%. Similarly, Gumieniak et al 5 found significantly higher serum TSH levels and significantly Blood pressure and TSH A Iqbal et al lower free T 4 index in 194 hypertensive subjects as compared with 90 normotensive subjects.…”