Evaluation of biochemical, hematological, and thyroid function parameters in nondipper and dipper hypertensive patients.

AIM OF THE STUDY: In this study we investigated the effects of biochemical, hematologic, and thyroid function parameters on the circadian rhythm of hypertensive patients whose 24-h ambulatory blood pressure was being followed.
METHODS: We studied the fasting glucose, urea, creatinine, uric acid, aspartate transaminase, alanine aminotransferase, gamma-glutamyl transferase, total protein, albumin, lipid profiles, sodium, potassium, hemoglobin, white blood cell count, platelet count, mean platelet volume, thyroid stimulating hormone, free thyroid hormone values obtained simultaneously with 24-h ambulatory blood pressure results, as documented in the case records of 470 patients. PATIENTS: Of the patients, 398 were in the nondipper hypertensive group and 72 in the dipper hypertensive group. Differences in serum biochemical, hematologic, and thyroid function parameters were compared between the groups.
RESULTS: No statistically meaningful difference was detected between the age, gender, biochemical and hematologic parameters of the two groups. When the two were compared with respect to thyroid function tests, thyroid stimulating hormone levels in the nondipper hypertensive group were significantly higher, while free triiodothyronine and thyroxine levels were significantly lower.
CONCLUSIONS: Thyroid function disorders are associated with hypertension. However, there are not enough data on the effects of thyroid hormones particularly on the nighttime blood pressure decrease in hypertensive patients. Although the exact mechanism between low thyroid hormone levels and nondipping hypertension development is not known, relatively low thyroid hormone levels in the nondipper group may be related to the decrease in vein wall compliance, considering the vascular effect of overt hypothyroidism.