A recent study published in JAMA examines the appropriateness of administering thyroid hormone therapy to patients with subclinical hypothyroidism.
Subclinical hypothyroidism describes the beginning stages of a condition when the thyroid does not produce enough hormones. This condition mostly affects older individuals and women, and is associated with symptoms such as weight gain and tiredness. One potential treatment for subclinical hypothyroidism is thyroid hormone replacement therapy. It aims to compensate for reduced production of thyroid hormone and to normalize their levels.
Few large-scale clinical trials have been conducted on subclinical hypothyroidism
There has been insufficient evidence and few large-scale clinical trials, however, to guide decision-making for physicians treating subclinical hypothyroidism. Hence, a group from Switzerland performed a systematic review and meta-analysis to consolidate the available evidence in order to improve clinical decision-making. They published their findings in JAMA.
The group searched for relevant randomized clinical trial studies and initially identified 3088 publications. This large number of studies was then filtered based on important criteria such as the presence of a thyroid hormone analyzed 21 randomized clinical trials for clinical hypothyroidism, across which included 2192 non-pregnant adults with the condition. For greater reliability, the selection process was independently done by two different reviewers.
No noticeable benefits and did not improve quality of life in general
Among these 21 studies, thyroid hormone replacement therapy was not associated with any noticeable benefit in outcomes. More specifically, the therapies overall did not improve general quality of life nor thyroid-related quality of life for the participants. Moreover, other outcomes such as depressive symptoms, cognitive function, muscle strength, blood pressure, and body mass index did not show any significant change when treated with hormone therapy as compared to a placebo control.
Treatment guidelines may have to be altered
This study, compared to previous ones, included the two largest randomized clinical trials to date that were recently published. With the additional data, the authors of the study provided evidence that thyroid hormone replacement therapy is no better than the absence of treatment. These results could have impact all over the world for physicians who encounter patients with subclinical hypothyroidism. Treatment guidelines may have to be altered and the resulting changes may save on health spending without impacting the health of patients.
Written by Branson Chen, BHSc
Reference: Feller M, Snel M, Moutzouri E, Bauer DC, de Montmollin M, Aujesky D, Ford I, Gussekloo J, Kearney PM, Mooijaart S, Quinn T. Association of thyroid hormone therapy with quality of life and thyroid-related symptoms in patients with subclinical hypothyroidism: a systematic review and meta-analysis. JAMA. 2018 Oct 2;320(13):1349-59.