The Effect of Early Substitution of Subclinical Hypothyroidism on Biochemical Blood Parameters and the Quality of Life

Abstract

SummaryBackgroundSubclinical hypothyroidism (SCH) is defined as high TSH and normal thyroxine. Data on the effects of early substitution by levothyroxine on psychophysical health in SCH are still not consistent enough to support its introduction.MethodsClinical parameters, biochemical data and quality of life (Short Form 36 questionnaire) were measured before the intervention and 3 months after the euthyroid state had been achieved in SCH patients.ResultsSignificant reduction in body weight (p=0.030), systolic and diastolic blood pressure (p=0.024, p=0.019), homocysteine (p<0.001), leukocytes and neutrophils (p=0.011, p=0.001), INR (p=0.049), K levels (p=0.040, p=0.013), HbA1c (p=0.001), fasting insulin (p<0.001) and insulin resistance measured by HOMA index (p<0.001), lipid parameters (total cholesterol (p<0.001), LDL-cholesterol (p<0.001), triglycerides (p=0.007), apoB (p=0.022), Lp(a) (p<0.001), LDL/HDL (p=0.008), LAP (p=0.04) and apoB/apoA1 ratios (p<0.023)), TSH (p<0.001) and tAbs (p<0.001) was recorded. Frequency of fatty liver (20% to 2.9%, p=0.016), hyperlipidemia (85% to 65.7%, p=0.001) and metabolic syndrome (34.3% to 2.9%, p=0.070) significantly decreased. A statistically significant positive association was found between the average dose of levothyroxine and changes in physical functioning (r=0.391, p=0.020), vitality (r=0.393, p=0.020), mental health (r=0.374, p=0.027) and overall dimensions of mental health (r=0.376, p=0.026). With increasing doses of levothyroxine, the previously listed scores of SF 36 grew (r=0.296, p=0.084).ConclusionsEarly substitution of SCH improved the many clinical and biochemical parameters related to cardiovascular risk. Quality of life was also improved, and correlated only with thyroxine doses suggesting an indirect relationship between the degree of hypothyroidism and quality of life.

Lowered quality of life in mood disorders is associated with increased neuro‐oxidative stress and basal thyroid‐stimulating hormone levels and use of anticonvulsant mood stabilizers

“…While increased nitro‐oxidative stress appears to exert its negative effects from normal to moderately low HRQoL values, CMPAase activity and TSH levels may further decrease HRQoL to the very low HRQoL range. Previously, it was observed that thyroid disorders may negatively impact QoL and that treatment with thyroid hormones may improve QoL . One explanation is that thyroid hormones mediate symptoms that play a role in HRQoL, including fatigue, feeling cold, and weight gain .…”

“…Furthermore, hypothalamic‐pituitary‐thyroid activity shows modest changes in MDD (lowered serum basal thyroid‐stimulating hormone [TSH] levels) and BD (increase in basal TSH), while subclinical hyperthyroidism and hypothyroidism may impact HRQoL . Treatments for subclinical hypothyroidism with thyroxine may improve HRQoL . Nevertheless, there are no data as to whether increased nitro‐oxidative stress, increased MDA and AOPP levels, and alterations in basal TSH levels could impact HRQoL among patients with mood disorders.…”

The current debate over treatment of subclinical hypothyroidism to prevent cardiovascular complications

“…Also, controversial statements from some studies that “subclinical hypothyroidism is a mild thyroid failure and should be treated”, 65 and from other that “the treatment of subclinical hypothyroidism is seldom necessary”, 66 make the decision to treat or not to treat these patients difficult. At present, because of the lack of long‐term outcomes studies regarding the beneficial or not effects of treatment of patients with SCH we should err on the beneficial aspect of treatment, since treatment of SCH with levothyroxine is simple, cheap and easy to administer, and is also, associated with improvement in BP, lipid changes and decreased incidence of CHD and HF 33,48‐49,51‐53,65‐72 . Overall, treatment of SCH is more beneficial in younger patients, but les beneficial in older patients (≥75 years of age).…”

“…In contrast to the previous studies, there are several other studies that demonstrate a beneficial effect of treatment in patients with SCH 47‐53 . The data from these studies are summarised in Table 3 and they will be, briefly, discussed here.…”

“…This small study showed that patients with SCH have endothelial dysfunction, which is improved with treatment and suggest a beneficial CV effects long‐term. The study by Pandrc et al, 51 is a prospective open‐label study on the psychosomatic effects of levothyroxine in patients with SCH. In this study, 35 patients with SCH, mean age 51.6 years and TSH levels up 10 mIU/L with normal FT4 and positive thyroid antibodies, were treated with levothyroxine for 3 months to euthyroid state.…”