BACKGROUND
Hypothyroidism is a common clinical condition. In this condition, the thyroid gland is not producing enough thyroid hormone. The treatment of this condition is replacement of the thyroid hormone, usually in the form of a medication called levothyroxine. However, a significant proportion of patients with hypothyroidism (up to 15%) experience persistent symptoms that affect their quality of life, and the reasons for this are not well understood.

This study aimed to investigate how patients use levothyroxine in real life, focusing on taking the medication regularly, timing of taking the medication, and drug interactions. The study also assessed the effectiveness of levothyroxine in keeping thyroid levels in the normal range as indicated by TSH levels, and health-related quality of life questionnaires (HRQoL) to determine whether correct levothyroxine use is associated with better thyroid health.

THE FULL ARTICLE TITLE
Mehuys E et al 2023 Investigating levothyroxine use and its association with thyroid health in patients with hypothyroidism: A community pharmacy study. Thyroid 33:918–926. PMID: 37184683.

SUMMARY OF THE STUDY
This clinical study was done in Belgium in 2018/2019. The study enrolled 856 adults who had been using levothyroxine for at least 2 years and were 18 years of age or older. The average age of the participants was about 61 years. Most of the patients were female. Participants completed questionnaires. Patient adherence to treatment including the timing of the dose and whether it was taken regularly were reviewed.

The authors also studied whether other medications were taken at the same time and what was the effect of levothyroxine on patient’s health quality. Blood test data for TSH levels were reviewed to look at whether treatment was keeping the thyroid levels in the normal range.

The study showed that 25% of patients did not have a normal blood level of TSH. Further, 28% were missing doses based on prescription refills, with the main reason unintentional owing primarily due to forgetfulness. Only 39% of the patients reported taking the medication at the recommended time 30 min before eating. About 7% of participants also used medications that could interfere with levothyroxine absorption and did not follow the recommended dosing instructions with regard to timing. However, the health questionnaires did not show a significant impact on the thyroid health or quality of life assessed by the patients themselves.

WHAT ARE THE IMPLICATIONS OF THIS STUDY?
The study showed that treatment with levothyroxine was not always optimal. This included whether patients were taking the medication as prescribed daily, at the correct time and without any interfering medications. However, it did not appear to affect the quality of life for most patients. Further studies to look at and understand the effect of thyroid hormone treatment on the outcomes of quality of life in patients on thyroid hormone replacement therapy are needed. Healthcare providers should continue to emphasize patient education on the importance of timing and dosing of the medication.

— Vibhavasu Sharma,MD,FACE

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