BACKGROUND
Hypothyroidism, or underactive thyroid, is common, with symptoms including fatigue, constipation, dry skin and weight gain. Hypothyroidism is treated by thyroid hormone replacement in the form of levothyroxine, the main hormone the thyroid makes. While the symptoms of most hypothyroid patients resolve on levothyroxine (T4), about 15% still report symptoms despite achieving normal serum thyroid hormones levels. It is unclear why these patients still experience symptoms. Some potential causes include not having all the thyroid levels back to normal and the worry of having a chronic disease or an autoimmune cause, among other causes. Options to address these symptoms have included adding the other thyroid hormone, triiodothyrodine (T3) to the levothyroxine replacement or changing to desiccated thyroid, which is dehydrated thyroid extract. These treatment options have varying results.

In this study, the authors analyzed if some personality traits could be the association between hypothyroidism and residual symptoms, especially, type D personality, which is characterized by a tendency to pessimism, worry, and negativity. This personality trait has been associated with persistent symptoms in other conditions, such as heart problems.

THE FULL ARTICLE TITLE
Perros P, et al. Hypothyroidism and type D personality: results from E-MPATHY, a cross-sectional international online patient survey. J Clin Endocrinol Metab. Epub 2024 Apr 9; doi: 10.1210/clinem/dgae140. PMID: 38591918.

SUMMARY OF THE STUDY
A survey was conducted by affiliates and partners of the patient advocacy group Thyroid Federation International via social media and web pages from 68 countries between April 2020 and January 2021, during COVID-19 pandemic. In addition to personality assessment, the survey included questions to assess: (i) control of symptoms of hypothyroidism by medication, (ii) satisfaction with treatment and care for hypothyroidism, and (iii) impact of hypothyroidism on everyday quality of life.

The survey received 3523 responses, of which 94.3% were women, 89.1% were white, 74.3% were employed, 87.1% had received more than 8 years of education, 75.1% were treated with levothyroxine alone, and about 20% were treated levothyroxine and T3 or desiccated thyroid extract. Around 16% of the ones who responded had no other medical conditions. In addition, 54.2% of the respondents had type D personality. Type D personality was found to be associated with other medical problems such as mental illness. In addition, type D personality was associated with dissatisfaction with the thyroid medication controlling symptoms, with care and treatment of hypothyroidism, and with a negative impact on quality of life.

WHAT ARE THE IMPLICATIONS OF THIS STUDY?
This study showed that type D personality was present in the majority of patients with hypothyroidism that responded to this survey. This suggests that having type D personality may be associated with negative patient-related outcomes in hypothyroidism. Further studies are needed to sort out this association.

—Joanna Miragaya, MD

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