Thyroxine Therapy Improves QoL in Subclinical Hypothyroidism

Pam Harrison

September 26, 2012

September 26, 2012 (Quebec City, Quebec) — Thyroxine therapy significantly improves quality of life in patients with subclinical hypothyroidism (SCH), researchers have shown.

Deshmukh Vaishali, MD, and colleagues from the Nair Hospital & Research Centre in Mumbai, India, found significant improvements in the domains of physical, affective, and social problems, as well as in overall quality of life in adults with SCH treated with L-thyroxine 50 µg/day for 6 months. The dose of L-thyroxine was titrated to achieve euthyroidism.

In contrast, about one third of patients whose SCH was not treated had disease progression and a subsequent worsening in their quality of life.

"The baseline score for quality of life increased significantly at 6 months for patients receiving active therapy, whereas untreated patients tended to deteriorate," Dr. Vaishali told Medscape Medical News.

"We clearly showed that thyroxine therapy not only reduced biochemical abnormalities and clinical mortality, it improved quality of life," she added.

The study results were presented here at the American Thyroid Association 82nd Annual Meeting.

Two Schools of Thought

As Dr. Vaishali pointed out that there are 2 schools of thought when it comes to SCH. "One school says there is no need to treat SCH because it is only a biochemical entity; the other school feels it is a clinical entity, that it is associated with symptoms, and that it should be treated," she explained.

In a group of 65 patients, the investigators initially tracked symptoms reported by SCH patients and by euthyroid control subjects.

When they evaluated quality-of-life scores in the 2 groups, they found that SCH patients had significantly lower scores than control subjects in physical, cognitive, social, ego, and overall quality-of-life domains.

Quality-of-Life (QoL) Scores in SCH and Control Subjects

Domain SCH Group Control Group P Value
Physical problems 59.6 80.56 2.18 × 10–⁵
Cognitive problems 83.8 95.6 .002
Social problems 90.7 96.7 .05
Ego problems 87.2 92.7 .011
Overall QoL 82.5 91.7 .001

Thyroxine Therapy

The investigators went on to study the effect of thyroxine therapy on quality-of-life outcomes in the same group of patients after 6 months of treatment.

Thirty were randomized to receive active therapy and 35 were randomized to receive only lifestyle intervention (control group). After 6 months of treatment, serum thyroid-stimulating hormone (TSH) levels had dropped significantly in the treatment group. TSH levels had not changed or had normalized in only 30% of the control group, had increased in 30%, and had decreased 40%.

Quality-of-life scores for physical problems also significantly improved at 6 months, from approximately 60.0 at baseline in both groups to 86.4 in the treatment group and 48.1 in the control group.

In the treatment group, ankle edema, irritability, and memory loss improved, and patients lost weight. In the control group, dry skin, constipation, irritability, cold intolerance, alopecia, dry hair, myalgia, and sweating abnormalities continued.

There was more improvement in menstrual dysfunction in women in the treatment group than in the control group (61% vs 16%). There was also a greater reduction in goiter size in the treatment group than in the control group (48% vs 14%).

Quality-of-life scores in the treatment group increased significantly, from 85.2 at baseline to 91.3 at 6 months. In contrast, overall quality-of-life scores did not change significantly in the control group, and remained at approximately 80.0 at both time points.

"Our study shows there are significant symptoms with SCH," Dr. Vaishali said, "and that these mostly physical symptoms improve with treatment."

David Cooper, MD, from the Johns Hopkins University School of Medicine in Baltimore, Maryland, thinks the study is problematic because the investigators did not indicate whether the 2 groups were equally matched for age, sex, and baseline thyroid function test. It's therefore difficult to determine if they were equally sick at study entry, he said.

He noted that the study, although randomized, was not a placebo-controlled trial, because "some people got medication and others got nothing. Every time you give people something, they are going to feel better," he explained.

Dr. Cooper also noted people who are hyperthyroid often feel better than those who are euthyroid, and that it's not clear whether those who received L-thyroxine in the study were overtreated.

"Therefore, we can't conclude from this study that treating SCH with L-thyroxine therapy is the best thing to do," Dr. Cooper said.

Dr. Vaishali and Dr. Cooper have disclosed no relevant financial relationships.

American Thyroid Association (ATA) 82nd Annual Meeting. Posters 124 and 125. Presented September 21, 2012.