WASHINGTON – according to a new study.
Jennifer Reising/MDedge News
Dr. Mirah Stuber
The double-blind, randomized, placebo-controlled, parallel-group trial used subsets of data from the TRUST study. This new research, which was presented at the Annual Meeting of the Society of General Internal Medicine, provides further evidence that prescribing levothyroxine to older patients with subclinical hypothyroidism will not reduce fatigue.
Like the findings in the TRUST study, the new study, “Effect of Thyroid Hormone Replacement on Fatigability in Older Adults with Subclinical Hypothyroidism: A Randomized Placebo Controlled Trial,” showed that the use of levothyroxine in subclinical hypothyroidism was not effective in changing physical and mental fatigability in older adults.
“This study shows that levothyroxine treatment may not be necessary and results in high costs and side effects,” noted Mirah Stuber, MD, during her presentation of the findings at the meeting.
The new study examined the effect of levothyroxine on the tiredness of older adults but with a more detailed analysis of fatigue than the full TRUST study provided. In this new study, investigators used a new assessment tool, called the Pittsburgh Fatigability Scale (PFS), a 10-item self-administered questionnaire that can measure both physical and mental fatigability. Perceived fatigability anchors tiredness to a set of activities and has been shown to be a more sensitive measure than global fatigue, explained Dr. Stuber of the University of Chicago.
The scores range from 0-50, with higher scores indicating higher fatigability. The scales were divided between mental and physical activities and measured fatigue in relation to a defined activity of a specific duration and intensity. These activities included a leisurely 30-minute walk and participation in a 1-hour social activity.
This study involved 230 participants from Switzerland and Ireland, with a mean age of 73.4 years, who had persistent hypothyroidism. The population was randomized to 119 patients who were administered levothyroxine and 111 patients who received a placebo.
At baseline, the levothyroxine group had a mean physical PFS score of 14.7 ± 9.3, and the placebo group had a score of 11.1 ± 9.1. The baseline mean mental PFS score for the levothyroxine group was 7.4 ± 8.0, while it was 5.1 ± 6.9 for the placebo group.
After 12 months of the participants’ use of levothyroxine or placebo, the physical PFS scores increased for both the treatment and placebo groups. For the levothyroxine group, the mean physical PFS score was 14.8 ± 9.6, while it was 12.4 ± 9.3 for the placebo group (P = 0.88). The investigators found no significant differences between these scores for the levothyroxine and placebo groups.
The mean mental PFS score slightly decreased to 6.0 ± 7.8 for the levothyroxine group, while it slightly increased to 6.0 ± 8.0 for the placebo group (P = 0.26) at 12 months. The difference between the mental fatigability scores for the levothyroxine and placebo arms at 12 months was also not significant.
The physical fatigability between-group difference was 0.2 (95% confidence interval, –1.8 to 2.1; P = 0.88), while the mental fatigability difference was –1.0 (95% CI, –2.8 to 0.8; P = 0.26).
The study was funded by the European Union FP7 and the Swiss National Science Foundation. Merck KGaA, Darmstadt (Germany) provided levothyroxine and the placebo. Dr. Stuber has no conflicts of interest.