Background: Primary hypothyroidism affects about 3% of the general population (5.1% women and 0.9% men). The majority of people are treated adequately with levothyroxine. However about 510% of hypothyroid patients (representing between 75 000 and 150 000 adults in the UK) continue to experience profound and sometimes disabling symptoms, such as fatigue/depression/impaired cognition, in spite of being adequately replaced biochemically. Before any trial of alternatives to levothyroxine (eg natural desiccated thyroid (NDT)) it is important to evaluate the appropriateness of health outcome measures, estimate how patient self-reported outcomes compare with other chronic disorders, and assess variability in response to inform sample size calculations.
Methods: Individuals were recruited with the help of Thyroid UK. All were judged to be clinically resistant to levothyroxine despite being biochemically euthyroid (TSH within laboratory reference range). They were invited to complete on-line a validated multi-attribute health utility instrument, the EuroQol EQ-5D-5L questionnaire and accompanying EQ-VAS (visual analogue scale. EQ-5D-5L index values (utilities, a preference-weighted measure of patients health valuation) were estimated based on the EQ-5D-5L cross walk value set for the UK.
Results: Responses were available from 31 people. Mean (S.D., min, max) EQ-5D-5L utility was 0.54 (0.23, 0.00, 0.84); and EQ-VAS was 49.4 (16.2, 10.0, 80.0). 26/31 (84%) individuals reported having moderate problems in at least one attribute, most often their ability to perform usual activities, and anxiety or depression; 10/31 (32%) reported severe problems; and 4/31 (13%) reported extreme problems.
Conclusion: As the first assessment of EQ-5D-5L utilities in this patient group, our findings provide a basis for powering a trial of alternative treatment options to levothyroxine. Reported health utilities in these individuals are comparable to those reported by patients with lung cancer, or acute cerebrovascular disease and would rank in the bottom decile of 100 chronic diseases.