QUALITY OF LIFE IN PATIENTS WITH BENIGN THYROID DISORDERS: A LITERATURE REVIEW

The importance of patient-reported outcomes such as health-related quality of life (HRQL) in clinical research is increasingly acknowledged. In order to yield valid results, the measurement properties of HRQL questionnaires must be thoroughly investigated. One aspect of such a validation process is the demonstration of content validity, i.e. that the questionnaire covers all relevant aspects. We review studies reporting on consequences of thyroid disorders and present the frequency of identified aspects, both overall HRQL issues and classical thyroid symptoms, in order to evaluate which issues are relevant for patients with thyroid diseases. Furthermore, existing questionnaires for thyroid patients are reviewed. A systematic search was performed in the Medline, Cinahl and Psycinfo databases and the reference lists of the relevant articles were hand-searched. Seventy-five relevant studies were identified. According to these studies, patients with untreated thyroid disease suffer from a wide range of symptoms and have major impairment in most areas of HRQL. Furthermore, the studies indicate that impairments in HRQL are also frequent in the long term. Six HRQL questionnaires for thyroid patients were identified. Generally, data supporting the validity of these questionnaires were sparse. According to the available literature, the quality of life of thyroid patients is substantially impaired over a wide range of aspects of HRQL in the untreated phase and continues to be so in many patients also in the long term. Studies systematically exploring the relative importance of these various aspects to thyroid patients are lacking, as is a comprehensive, validated thyroid-specific HRQL questionnaire. Key Words: Quality of Life, Patients, Thyroid Disorders, Review