Endocrine Abstracts

‘Nondippers’ are individuals with absence of anticipated nocturnal decrease in blood pressure (BP) and increased incidence of target organ damage. The pathogenesis of nondipper hypertension is not clear at present. We aimed to investigate the effect of overt and subclinical hypothyroidism on the development of nondipper blood pressure pattern via 24-hour ambulatory blood pressure monitoring. One hundred and nine normotensive patients with overt and subclinical hypothyroidism were evaluated and 95 of these patients without reverse dipping and masked hypertension were included in the study. Seventy-five out of 83 normotensive and euthyroid individuals were included in the control group. Median serum TSH levels were 7.61 and 1.59 in patient and control groups, respectively. The number of dipper individuals according to systolic (SBP), diastolic (DBP) and mean arterial pessure (MAP) measurements were 28/95 (29.5%), 55/95 (57.9%) and 38/95 (40%) in the patient group and 43/75 (57.3%), 61/75 (81.3%) and 54/75 (72%) in the control group, respectively. The differences between groups were significant for all 3 parameters (P<0.001). When patients with overt hypothyroidism and subclinical hypothyroidism were individually compared with control group, the differences were still significant for dipping pattern in SBP,DBP and MAP measurements. Spearman’s test was used to analyze the correlations between nondipper pattern and serum TSH, fT3, fT4 levels, smoking status, BMI, age and sex; the only significance was a negative correlation between TSH and dipping in SBP, DBP and MAP. Consequently, despite the fact that how hypothyroidism affects nondipper BP pattern is not known, this pattern is more frequent in patients with hypothyroidism. It has an increased frequency even in patients with subclinical hypothyroidism. When the adverse effects of nondipper BP profile is taken into consideration, the necessity of thyroid hormone replacement therapy in patients with subclincal hypothyroidism becomes more clear.