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Levothyroxine fails to benefit elderly patients with subclinical hypothyroidism
Older adults with subclinical hypothyroidism treated with levothyroxine did not experience an improvement in symptoms or quality of life measures compared with similar adults assigned placebo, according to findings published in JAMA.
“Individuals aged 80 years and older with subclinical hypothyroidism have been underrepresented in clinical trials and outcomes such as quality of life have not been reported for this age group,” Simon P. Mooijaart, MD, PhD, an internist and geriatrician in the department of gerontology and geriatrics at the Leiden University Medical Center in the Netherlands, and colleagues wrote. “The lack of evidence for older patients may have contributed to significant treatment variation by primary care clinicians.”
Mooijaart and colleagues analyzed data from 251 adults aged at least 80 years with subclinical hypothyroidism (mean age, 84.6 years; 47% women) who took part in the Institute for Evidence-based Medicine in Old Age (IEMO) trial or the Thyroid Hormone Replacement for Untreated Older Adults with Subclinical Hypothyroidism Trial (TRUST). Researchers in each trial randomly assigned a daily regimen of levothyroxine or placebo to participants. At baseline and at 12 months, participants completed the Thyroid-Related Quality of Life Patient-Reported Outcome (ThyPRO) questionnaire, which included questions about hypothyroid symptoms and fatigue. The researchers noted that higher scores indicate more symptoms.
Mooijaart and colleagues found that participants who were assigned to levothyroxine treatment experienced a 1.9 mIU/L greater decrease in thyrotropin levels from baseline to 12 months compared with those who were assigned placebo (P < .001). However, based on scores to the ThyPRO questionnaire, the researchers noted that both hypothyroid symptoms and fatigue were not significantly affected by levothyroxine treatment vs. placebo. In addition, measure of general quality of life, thyroid-specific quality of life, activities of daily living and executive cognitive function and physical function did not differ by a significant margin when comparing levothyroxine treatment with placebo. Among those assigned to levothyroxine treatment, at least one serious adverse event was reported in 33 participants. Among those assigned to placebo, at least one serious adverse event was reported in 40 participants.
Between baseline and 12 months, the researchers found that BMI was increased by 0.38 kg/m2 more (P = .01) and that waist circumference was increased by 1.52 cm more (P = .04) among those assigned to levothyroxine compared with those assigned to placebo.
“Treatment with levothyroxine, compared with placebo, was not significantly associated with improvement in hypothyroid symptoms or fatigue,” the researchers wrote. “These findings do not support routine use of levothyroxine for treatment of subclinical hypothyroidism in adults aged 80 years and older.”
In an editorial published in JAMA, Anne R. Cappola, MD, ScM, of the division of endocrinology, diabetes and metabolism at the Perelman School of Medicine at the University of Pennsylvania, wrote that these findings “should change clinical practice,” particularly when it comes to thyrotropin assessment.
“The most consequential implication of this study is that the upper limit of the thyrotropin range should be raised to 7 mIU/L among individuals aged 80 years and older,” Cappola wrote. “If the reference range were changed for individuals aged 80 years and older, it would eliminate the need for clinicians to explain why a test result that is outside the reference range can be ignored without additional follow-up. It would help protect against polypharmacy in a vulnerable population.”
Cappola also noted that due to the “frequently transient” nature of subclinical hypothyroidism, confirmatory assessments are necessary.
“Subclinical hypothyroidism that resolves without intervention does not need treatment,” Cappola wrote. “Patients with subclinical hypothyroidism should have thyroid function testing repeated, without initiating treatment, at least 1month after initial testing to confirm persistent subclinical hypothyroidism.” – by Phil Neuffer
Disclosures: Mooijaart reports he has received grants from ZonMW and nonfinancial support from Merck. Please see the study for all other authors’ relevant financial disclosures. Cappola reports no relevant financial disclosures.
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