Validity and Reliability of the Korean Version of the Hyperthyroidism Symptom Scale

BACKGROUND Thyrotoxicosis is a common disease resulting from an excess of thyroid hormones, which affects many organ systems. The clinical symptoms and signs are relatively nonspecific and can vary depending on age, sex, comorbidities, and the duration and cause of the disease. Several symptom rating scales have been developed in an attempt to assess these symptoms objectively and have been applied to diagnosis or to evaluation of the response to treatment. The aim of this study was to assess the reliability and validity of the Korean version of the hyperthyroidism symptom scale (K-HSS). METHODS Twenty-eight thyrotoxic patients and 10 healthy subjects completed the K-HSS at baseline and after follow-up at Seoul National University Bundang Hospital. The correlation between K-HSS scores and thyroid function was analyzed. K-HSS scores were compared between baseline and follow-up in patient and control groups. Cronbach's α coefficient was calculated to demonstrate the internal consistency of K-HSS. RESULTS The mean age of the participants was 34.7±9.8 years and 13 (34.2%) were men. K-HSS scores demonstrated a significant positive correlation with serum free thyroxine concentration and decreased significantly with improved thyroid function. K-HSS scores were highest in subclinically thyrotoxic subjects, lower in patients who were euthyroid after treatment, and lowest in the control group at follow-up, but these differences were not significant. Cronbach's α coefficient for the K-HSS was 0.86. CONCLUSION The K-HSS is a reliable and valid instrument for evaluating symptoms of thyrotoxicosis in Korean patients.