Purpose: It has been suggested that increasing levothyroxine dose to lower TSH levels within the normal laboratory range might be a therapeutic option for patients with apparently well-controlled primary hypothyroidism who are dissatisfied with their treatment and complain of physical or psychological symptoms. This study assessed whether there is a relationship between TSH levels and health-related quality of life (HRQoL) among subjects with adequately treated hypothyroidism.
Methods: HRQoL was measured with the specific thyroid disease ThyPRO-39 questionnaire in 218 consecutive patients with primary hypothyroidism of any cause attending an Endocrinology Department in a single center. Patients had TSH values within the normal laboratory range on a blood test performed not before than 6 weeks prior to study participation, but they were not aware of their lab results. The association between TSH values and the different ThyPRO-39 scales was analyzed by means of multiple regression models, both linear and additive, in which, in addition to TSH, a wide set of clinical and sociodemographic variables potentially related to HRQoL were also considered.
Results: TSH levels and the use of anxiolytic and antidepressant drugs were the only variables that showed a positive linear correlation with the ThyPRO-39 composite scale in the multivariate regression analysis, indicating greater impairment in HRQoL with increasing TSH values. TSH was also independently correlated to scores of scales dealing on tiredness and emotional susceptibility.
Conclusions: In patients with primary hypothyroidism, higher TSH values, even within the normal reference range, are associated with greater deterioration of HRQoL.
Keywords: Hypothyroidism; Levothyroxine; Patient-reported outcome; Quality of life; TSH.