Fatigue and fatigue-related symptoms in patients treated for different causes of hypothyroidism
M Louwerens, BC Appelhof, H Verloop, M Medici, RP Peeters, TJ Visser, A Boelen, E Fliers, JWA Smit en OM Dekkers
ObjectiveResearch on determinants of well-being in patients on thyroid hormone replacement is warranted, since persistent fatigue-related complaints are common in this population. In this study we evaluated the impact of different states of hypothyroidism on fatigue and fatigue-related symptoms. Furthermore the relationship between fatigue and the TSHR-Asp727Glu polymorphism, a common genetic variant of the thyroid stimulating hormone receptor (TSHR), was analysed.
DesignA cross-sectional study was performed in 278 patients (140 patients treated for differentiated thyroid carcinoma (DTC) and 138 with autoimmune hypothyroidism (AIH)) genotyped for the TSHR-Asp727Glu polymorphism.
DTC = differentiated thyroid carcinoma
AIH = autoimmune hypothyroidism
MethodsThe multidimensional fatigue inventory (MFI-20) was used to assess fatigue, higher MFI-20 scores indicating more fatigue-related complaints. MFI-20 scores were related to disease status and Asp727Glu polymorphism status.
Results and conclusionsAIH patients scored significantly higher than DTC patients on all five MFI-20 subscales (p <0.001), independent of clinical and thyroid hormone parameters. The frequency of the TSHR-Glu727 allele was 7.2%. Heterozygous DTC patients had more favourable MFI-20 scores than wild-type DTC patients on 4 of 5 subscales. The modest effect of the TSHR-Asp727Glu polymorphism on fatigue was found in DTC patients only.
AIH patients had significantly higher levels of fatigue compared to DTC patients, which could not be attributed to clinical or thyroid hormone parameters. The modest effect of the TSHR-Asp727Glu polymorphism on fatigue in DTC patients should be confirmed in other cohorts.