High rates of fatigue in newly diagnosed Graves' disease

Abstract

Background: Fatigue in patients with Graves’ disease has rarely been addressed. Purpose: To investigate the presence of subjective fatigue as well as cognitive fatigability among patients with untreated Graves' disease. Methods: Thirty-four patients (mean age: 39.2 ± 9.8) with newly diagnosed untreated Graves' disease and 31 healthy controls (mean age 36.7 ± 8.8) were investigated. The Digit Symbol Substitution Test was used for assessment of cognitive fatigability and the Fatigue Severity Scale (FSS) and the Everyday Consequences of Fatigue (ECF) questionnaire were used to assess self-rated effects of fatigue on activities and motivation. Results: Patients scored significantly higher on self-rated fatigue impact (FSS) than controls (p < 0.001) and 56% of patients reached a clinical level of fatigue impact. Half of the patients suffered from cognitive fatigability compared to 19% of the controls (p = 0.010). High free triiodothyronine (T3) levels were associated with ECF scores. Depression was associated with self-rated fatigue impact but not with cognitive fatigability. Free T3 correlated significantly with consequences of fatigue among the fatigued patients, while free T3 correlated significantly with incidental memory among the non-fatigued patients. Conclusions: The results suggest that both subjective fatigue impact and cognitive fatigability are common in untreated Graves' disease and that thyroid hormone levels might have differential effects on fatigue impact and memory in different individuals.