The purpose of this study is to evaluate whether low-level Laser therapy is effective in ameliorating the thyroid function of patients with hypothyroidism caused by chronic autoimmune thyroiditis.
Chronic autoimmune thyroiditis (CAT) is the most common cause of hypothyroidism in iodine-replete areas. An autoimmune dysfunction causes humoral and cellular responses that lead progressively to thyroiditis. There is no effective therapy available that can change the natural history of CAT, which presents a high incidence of hypothyroidism and requires continuous treatment with levothyroxine (LT4). Laser light can be valuable since the local and systemic actions of low-level laser therapy (LLLT) have been shown to be effective in treating autoimmune diseases, such as rheumatoid arthritis and Sjogren's syndrome. There is also evidence suggesting that LLLT can facilitate regeneration of various tissues and, in animal thyroids, can lead to improvement in microcirculation and increases in serum triiodothyronine (T3) and thyroxine (T4) levels. Since the LLLT is a non-invasive, cost-effective and painless procedure, the objective of this randomized clinical trial was to evaluate the effectiveness of LLLT in patients with hypothyroidism caused by chronic autoimmune thyroiditis, based on patients' thyroid function, their concentration of thyroid autoantibodies, and the parameters of their ultrasonography study.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
43
A continuous wave (CW) diode laser device (830nm, infrared) with a beam area of 0.2827cm2 and using the punctual method, continuous emission mode, output power of de 50mW and fluence of 70J/cm2 (40 seconds at the point of application).
University of Sao Paulo General Hospital
São Paulo, São Paulo, Brazil
The main outcome measure was to gauge the effectiveness of applying LLLT in patients with hypothyroidism caused by CAT evaluated by a significant reduction of the levothyroxine (LT4) mean dose (µ/day) 9 months post-LT4 withdrawal.
All patients enrolled in the study were undergoing LT4 treatment. They received 10 applications of LLLT or placebo. Thirty days after intervention, LT4 was discontinued in all patients and, if required, reintroduced. T3, T4, free T4 and TSH levels (all laboratory personnel was blinded), were assessed pre-LLLT and then 1, 2, 3, 6 and 9 months post-LT4 withdrawal. The LT4 mean dose pre-LLLT and 9 months post-LT4 withdrawal was compared both in face of normal levels of T3, T4, free T4 and TSH to evaluate LLLT effectiveness.
Time frame: LT4 dose, concentrations of T3, T4, free T4 and TSH were evaluated and compared before intervention and 9 months post-LT4 withdrawal.
Evaluate the LLLT efficacy in reducing thyroid autoantibodies concentrations.
Thyroid peroxidase (TPOAb) and thyroglobulin (TgAb) autoantibodies were both determined prior to LLLT and in the 1st, 2nd, 3rd, 6th and 9th months after LT4 withdrawal. All laboratory personnel was blinded to treatment assignment throughout the study.
Time frame: Thyroid autoantibodies were determined and compared pre-intervention and 9 months post-LT4 withdrawal.
Evaluate the LLLT efficacy by quantitative and qualitative ultrasonography parameters.
B-mode sonography (volume, texture and echogenicity using computerized histogram) as well as power Doppler (vascularization) and pulsed Doppler (maximal systolic peak velocity and resistance index for the thyroid arteries) were performed and compared pre- and 30 days post-intervention by only one experienced and blind investigator, during the use of the same doses of LT4.
Time frame: The ultrasonography parameters observed pre-LLLT were compared with those observed 30 days post-LLLT.
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