Endocrine Abstracts

Introduction: There is an increasing awareness for intrinsic imperfections of endocrine replacement therapy affecting general well-being in the long-term. For thyroid hormone, many factors affect the variable responses to hormone replacement, like common genetic variations in deiodinase and thyroid hormone transport proteins, and the inability to provide adequate individual combined T₄ and T₃ therapy. Despite levothyroxine (L-T₄) replacement in primary hypothyroidism and restoration of biochemical euthyroidism, many patients have persistent complaints that have anecdotally been associated to high levels of antibodies against TPO (anti-TPO).

Aim of the study: i) To assess quality of life (QoL) in patients with Hashimoto’s thyroiditis (HT) on adequate L-T₄ replacement and ii) to explore potential associations with serum TSH and anti-TPO.

Design: Cross-sectional, case–control study.

Patients and controls: One hundred and twenty patients on long-term L-T₄ replacement for HT (mean age 54.0±14.0 years, range 21–75 years) and 60 euthyroid control subjects (aged 53.1±12.4), matched for age, gender, and educational level.

Methods: Evaluation of FT₄, TSH, and anti-TPO concentrations, and of QoL as measured with the Short Form-36 Health Survey (SF-36) for mental health and vitality in both patients and controls. Patients and controls were subdivided into two age groups: 20–49 years (GR1) and 50–75 years (GR2), with a mean duration of L-T₄ replacement of 3.95 and 9.27 years respectively.

Results: FT₄ and FT₃ levels were not different between patients and controls, but TSH was slightly higher in Hashimoto patients (GR1 3.64±2.74 vs 1.93±1.10, P<0.05 and GR2 3.93±2.84 vs 1.91±0.90, P<0.05). SF-36 scores in the patients were significantly lower for both age groups compared with controls (patients vs controls): dimension A–physical health; GR1: 70.18±15.74 vs 76.54±13.71, P<0.05; GR2: 55.84±20.2 vs 75.1±121.0, P<0.01; SF-36 score GR1: 69.8±16.4 vs 76.4±14.1, P<0.05; GR2: 57.6±21.1 vs 73.7±14.2, P<0.05. In addition, in both groups anti-TPO levels, but not TSH, were associated with SF-36 scores subscale2 r=−0.208, P=0.029; subcale3 (body pain) r=−0.268, P=0.005; subcale4 (general health) r=−0.198, P=0.038; dimension A r=−0.224, P=0.019; and SF-36 score r=−0.191, P=0.046.

Conclusion: Patients on long-term L-T₄ replacement for HT have impaired QoL that is associated with higher anti-TPO levels.