Research Information System
Thesis Type: Expertise In Medicine
Institution Of The Thesis: Gazi University, Tıp Fakültesi, Turkey
Approval Date: 2008
Thesis Language: Turkish
Student: Salih İnal
Supervisor: MEHMET AYHAN KARAKOÇ
Abstract:“Nondippers” are individuals with absence of anticipated nocturnal decrease in blood pressure and increased incidence of target organ damage and a worse outcome cardiovascular events have been reported in this group of people. 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. 109 normotensive patients with overt and subclinical hypothyroidism, that had been diagnosed at internal medicine and endocrinology outpatient units between December 2007 and June 2008, were evaluated and 95 of these patients without reverse dipping and masked hypertension were included in the study. 75 out of 83 normotensive and euthyroid individuals, who attended for a routine internal medicine outpatient visit, were included in the control group. Median serum TSH levels were 7.61 and 1.59 in patient and control groups, respectively. Office measurements of systolic and diastolic blood pressure and day time systolic, diastolic and mean blood pressure levels in patient group were significantly higher than levels in control group. There was no statistically significant difference in ambulatory blood pressure measurements, other than daytime, between patient and control groups. Serum triglyceride (p=0.02) and LDL (p=0.03) levels were significantly higher in the hypothyroid group. The number of dipper individuals according to SBP, DBP and 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 blood pressure 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 blood pressure profile is taken into consideration, the necessity of thyroid hormone replacement therapy in patients with subclincal hypothyroidism becomes more clear.