Hashimoto's Thyroiditis Affects Symptom Load and Quality of Life Unrelated to Hypothyroidism: A Prospective Case–Control Study in Women Undergoing Thyroidectomy for Benign Goiter

Background: Hashimoto's thyroiditis (HT) is a common disease, and is the most prevalent cause of hypothyroidism. Symptoms and diseases associated with HT are considered to be caused by hypothyroidism. We hypothesized that higher antithyroperoxidase (anti-TPO) antibody levels would be associated with an increased symptom load and a decreased quality of life in a female euthyroid patient collective. Methods: In a prospective cohort study 426 consecutive euthyroid female patients undergoing thyroid surgery for benign thyroid disease were included. Main outcome measures were preoperative anti-TPO levels, a symptom questionnaire and the SF-36 questionnaire, and lymphocytic infiltration of the thyroid tissue as evaluated by histology. Results: Histology revealed HT in 28/426 (6.6%) subjects. To maximize the sum of the predictive values, a cut-off point for anti-TPO of 121.0 IU/mL was calculated (sensitivity 93.3% [95% confidence interval: 77.9%–99.0%]; specificity 94.7% [95% confidence interval: 92.0%–96.7%]) to predict the presence of histological signs of HT. The mean number of reported symptoms was significantly higher in patients with anti-TPO levels >121.0 IU/mL than in the other group (6.7 ± 2.5 vs. 4.1 ± 2.8; p