Is Thyroid Autoimmunity per se a Determinant of Quality of Life in Patients with Autoimmune Hypothyroidism?
OBJECTIVE
To evaluate the relationship between thyroid variables and health-related quality of life (QoL) in patients with autoimmune hypothyroidism, using the thyroid-specific QoL questionnaire ThyPRO.


METHODS
In a cross-sectional study, responses to the ThyPRO from 199 outpatients with autoimmune hypothyroidism were analyzed in relation to thyroid volume, thyroid function and markers of thyroid autoimmunity. Based on a classical QoL framework, we hypothesized that physiological dysfunction caused specific physical and psychological symptoms, which affected functioning and well-being, and consequently participation in life and QoL. These hypotheses were tested through multiple regression and multivariate path analysis models.


RESULTS
None of the thyroid function tests were associated with QoL scores. However, in the pairwise regression, the thyroid peroxidase antibody (TPOAb) level was associated with several QoL outcomes: Goitre Symptoms (p = 0.024), Depressivity (p = 0.004), Anxiety (p = 0.004), Emotional Susceptibility (p = 0.005) and Impaired Social Life (p = 0.047). In the multivariate model, the TPOAb level was related to Goitre Symptoms (r = 0.17, p = 0.019), Depressivity (r = 0.24, p = 0.001), and Anxiety (r = 0.23, p = 0.002), but no longer to Emotional Susceptibility or Impaired Social Life, indicating that the effect on these were mediated through an effect on the symptom scales (i.e. Goitre Symptoms, Depressivity and Anxiety).


CONCLUSIONS
Health-related QoL, evaluated with state-of-the-art QoL methodology, was related to TPOAb level but not to thyroid function. This raises the hypothesis that autoimmunity, independent of thyroid function, impacts on QoL in patients with autoimmune hypothyroidism, especially in terms of psychological symptoms. Longitudinal studies, in initially untreated patients, are needed to test this hypothesis.
Department of Endocrinology, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark ; Institute of Public Health, University of Copenhagen, Copenhagen, Denmark.
Torquil
T
Watt
Department of Endocrinology and Metabolism, Odense University Hospital, Odense, Denmark.
Laszlo
L
Hegedüs
Institute of Public Health, University of Copenhagen, Copenhagen, Denmark ; National Research Centre for the Working Environment, Copenhagen, Denmark.
Jakob Bue
JB
Bjorner
Institute of Public Health, University of Copenhagen, Copenhagen, Denmark ; Department of Palliative Medicine, Bispebjerg Hospital, Copenhagen, Denmark.
Mogens
M
Groenvold
Department of Endocrinology and Metabolism, Odense University Hospital, Odense, Denmark.
Steen Joop
SJ
Bonnema
Department of Endocrinology, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.
Ase Krogh
AK
Rasmussen
Department of Endocrinology, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.
Ulla
U
Feldt-Rasmussen
Autoimmune hypothyroidism; Autoimmunity; Clinical variables; Quality of life