Mean platelet volume in patients with subclinical hypothyroidism

Abstract

Subclinical hypothyroidism (SCH) is frequently encountered in the general population. Since it is generally asymptomatic, these patients are mostly identified through routine screening or evaluation of non-specific symptoms. It has been suggested as a risk factor for cardiovascular disease. On the other hand, mean platelet volume (MPV), which is a determinant of platelet function, is an independent risk factor for cardiovascular disease. The aim of this study was to evaluate MPV values in subclinical hypothyroidic patients when they were subclinical hypothyroidic and became euthyroidic after 12 weeks of levothyroxine replacement therapy. Sixty patients with subclinical hypothyroidism and 78 euthyroid healthy subjects matched for age, gender and body mass index were enrolled in the study. None of the study subject had diabetes, hypertension or dyslipidemia. All the study subjects were evaluated by biochemical and platelet parameters. Subclinical hypothyroidic patients were then reevaluated with the same parameters when they became euthyroid after 12 weeks of levothyroxine treatment. Platelet counts and metabolic parameters, except serum triglyceride and high density lipoprotein cholesterol (HDLC) levels, were similar between the two groups. Serum triglyceride and MPV values were significantly higher (pTG=0.007 and pMPV<0.001) while HDLC levels were lower (pHDLC=0.008) in the subclinical hypothyroidic group. MPV was found to be correlated with only antithyroid peroxidase (anti-TPO) antibody levels (P<0.001). MPV values were decreased after subclinical hypothyroidic patients became eythyroid. However, post-treatment MPV values were still higher (p=0.035) in the patient group than in control group. These results suggest that subjects with SCH are susceptible to increased platelet activation and increased MPV values which contribute to increased risk of cardiovascular complications.

Koncentracja hormonu tyreotropowego jako niezależny czynnik ryzyka żylnych powikłań zakrzepowo-zatorowych bez względu na czynność tarczycy

“…Recent reports showed that in subjects with subclinical hypothyroidism defined by elevated TSH levels above the normal rage, there was an increase in the mean platelet volume (MPV). Thus, in cases with TSH above the normal range, and even among subjects with upper TSH tertiles, the increased risk of VTE could be explained by larger and more activated platelets [20,21]. However, in our study we measured the platelet count and the mean platelet volume and we did not observe any significant differences.…”

The Mean Platelet Volume Is Positively Correlated with Serum Thyrotropin Concentrations in a Population of Healthy Subjects and Subjects with Unsuspected Subclinical Hypothyroidism

“…Currently, limited and conflicting data regarding the relationship between thyroid function and MPV have been reported in small-scale case-control studies (17)(18)(19)(20)(21)(22). To our knowledge, no study has been based on a general population, particularly in those who were thought to be healthy and euthyroid.…”

“…Van Doormaal et al (17) found small-sized platelets in overt hypothyroidism, whereas Ford et al (18) did not show smallsized platelets in overt hypothyroidism. Coban et al (19), Erikci et al (20), and Yilamz et al (21) reported an increased MPV in the SCH group compared with the euthyroid states. In premenopausal women with a low cardiac risk, overt hypothyroidism and SCH did not influence MPV (22).…”

Remarkable Hematological Laboratory Findings in Patients with Fibromyalgia Syndrome

“…These common problems between FMS and cardiovascular diseases suggest to investigate the relationship between FMS and cardiovascular diseases. Mean platelet volume (MPV) is a useful and important parameter because of its relationship with cardiovascular disorders (10,11). MPV is a parameter which is easy to access and an important finding of the platelet size, hereby of its prothrombotic potential.…”