Endocrine Abstracts

Background: It is controversial whether symptoms of hypothyroidism and quality of life (QoL) in people with subclinical hypothyroidism (SCH) are impaired and whether treatment with L-thyroxine alleviates these. Previous studies of L-Thyroxine therapy have shown conflicting results. No previous study has simultaneously 1investigated effects of treatment on quality of life (QoL), health status, symptoms and treatment satisfaction.

Methods: One hundred patients, aged between 18 to 80 years with SCH were identified from the laboratory database and from primary care practices. Exclusion criteria were previous thyroid disease, pregnancy, psychiatric disorders, chronic diseases, and medications affecting thyroid hormone levels. Ethical committee approval was obtained. All the patients were randomised in a double-blind cross- over manner to either L-Thyroxine (100 mcg) or matching placebo for a period of 12-weeks each. Assessments were made by validated patient-completed2 questionnaires: disease-specific instruments for QoL (ThyDQoL), symptoms (ThySC), and treatment satisfaction (ThyTQ15), and generic health status (SF-36 v2).

Results: Ninety-nine patients completed the study. Compared to placebo, L-thyroxine reduced TSH from 6.1 to 1.5 mIU/L (P<0.001), free T4 and free T3 levels increased significantly (P<0.01)3, and both sex-life (ThyDQoL) and overall QoL (ThyDQoL) were less negatively impacted by hypothyroidism [difference in means (95%CI)] 0.41 (0.04 to 0.78, P<0.04) and 0.18 (0.01 to 0.35, P<0.05), respectively. ThySC symptom bother scores did not show any benefit of L-Thyroxine but there was a significant improvement in the frequency of tiredness (ThySC) - from 89% to 78%, P<0.04, NNT=54. Health status and treatment satisfaction did not show any significant change.

Conclusions: Treatment of individuals with SCH with 100 mcg of L-thyroxine improves overall QoL and sex-life. The number of patients feeling tired reduces significantly but there is no improvement in any respondent ratings for symptom bother, perceived health status or satisfaction with treatment with L-thyroxine over and above that of placebo.