Endocrine Abstracts

Objective: Many patients receiving thyroid hormone replacement therapy complain of persistent lethargy and related symptoms even with normal TSH levels. However, it remains unclear whether this is related to thyroxine replacement or coincidental psychological morbidity.
Design: Using general practice computer records, 961 patients on thyroxine (minimum of 4 months) and their age- and sex-matched controls were identified and sent a two-page questionnaire, comprising the short form of the General Health Questionnaire (GHQ-12) and a 'thyroid symptom questionnaire' (TSQ) in the same format.
Results: 597(62%) of the patients (P) and 551 (57%) of the controls (C) responded. 397 responding patients (nP) had a TSH estimation performed in the previous 12 months with the last result being in the local laboratory normal range. The responding P, nP and C populations were well matched for age and sex. The number of individuals scoring 3 or more on the GHQ-12 (indicating 'caseness') was 21% higher in P vs. C (185/572 = 32.3% vs. 137/535 = 25.6% p <0.014) and 26% higher in nP vs. C (131/381 = 34.4% vs. 25.6% p<0.005). Stronger differences were seen with the TSQ scores. Though differences existed in chronic drug use and chronic disease prevalence between the control and patient groups, the scores between the groups remained significant even after correction for these factors as well as age and sex in multiple regression analysis.
Conclusions: This community-based study is the first evidence to indicate that patients on thyroxine replacement, even with a normal TSH, display significant impairment in their psychological well-being and to quantitate this. To explain the possible mechanisms for such reduced well-being, we are conducting a large (700 patients), randomised controlled trial of 12 months with partial replacement of T4 with T3.