Modifying influence of subclinical hypothyroidism on arterial hypertension: relationship to masked treatment failure, circadian blood pressure profile and target organs status

Abstract

Aim. The study aimed to investigate the modifying influence of subclinical hypothyroidism (SH) on arterial hypertension (AH), the prevalence of masked uncontrolled hypertension, circadian blood pressure (BP) profile and cardiovascular disorders. Materials and methods. We investigated twenty-four hours BP monitoring data and cardiovascular parameters in 101 hypertensive patients with normal thyroid function ( n = 45) or SH ( n = 56). Then, we observed 44 patients with AH and SH within six months; 24 of them received levothyroxine. Results. Patients with AH and SH had higher risk of masked uncontrolled hypertension (for TSH ≥ 5 mU/L, OR 1.9 [1.11, 3.26], p = 0.016); increased pulse BP, daily BP variability, non-dippers rate as well as more marked myocardial hypertrophy, arterial dysfunction and microcirculation deterioration ( p < 0.05 for all parameters). Levothyroxine therapy reduced the incidence of masked uncontrolled hypertension, ambulatory BP value, non-dippers rate and intensified microcirculation ( p < 0.05 for all parameters). Conclusion. SH is a risk factor for masked failure of antihypertensive therapy. SH impairs the profile of ambulatory BP and target organs damages in patients with AH. These disorders can be partly corrected by the use of levothyroxine.