Endocrine Abstracts

Introduction: Levothyroxine is the third most commonly prescribed medication in the UK, with an annual cost to the NHS of £52 million. Due to the fluctuating nature of thyroid function, guidelines for hypothyroidism management recommend that an elevated Thyroid Stimulating Hormone (TSH) should be confirmed with repeat testing, prior to commencing treatment. International research has demonstrated that levothyroxine is routinely prescribed contrary to such guidance and frequently for those with normal thyroid function. The goal of this research is to determine the acceptability of de-prescribing levothyroxine.

Methods: Patients registered with five general practices in North-East England were invited to participate. All were taking levothyroxine for at least six months and never had a documented TSH >10mU/L. Those with a history of thyroid cancer, thyroidectomy or pituitary disease were excluded. Participants discontinued levothyroxine for a six-week period. All completed a ThyPRO-39 quality of life questionnaire prior to intervention and again at the end of the study period, along with assessment of free T4, TSH & TPO antibodies at six weeks. The primary outcome was the proportion of patients who remain euthyroid, off levothyroxine, at 6 weeks.

Results: 102 participants were enrolled. 94 (92.2%) completed 6 weeks of levothyroxine withdrawal, with 8 patients restarting early, primarily due to symptoms. 60.8% of those completing the discontinuation period were either euthyroid or had TSH in the subclinical hypothyroidism range (4.4-10mU/L). 50% of those with subclinical hypothyroidism chose not to restart treatment at trial conclusion, with higher TPO-Ab levels positively predicting those who recommenced. 65.7% of the whole cohort reported feeling either “the same” or “better” at the end of the study period.

Conclusion: Most patients prescribed levothyroxine for presumed primary hypothyroidism do not develop overt hypothyroidism 6 weeks after discontinuation of medication, highlighting the potential for de-prescribing levothyroxine in select patients, without impacting patient well-being.