Quality of life, muscle strength, and fatigue perception in patients on suppressive therapy with levothyroxine for differentiated thyroid carcinoma.

OBJECTIVES: The aim of this study was to evaluate the fatigue perception, the muscle function, and the health-related quality of life (QoL) in subclinical hyperthyroidism (SCH) induced by levothyroxine in the treatment of differentiated thyroid carcinoma, in comparison with a group of euthyroid (EU) subjects. PATIENTS AND METHODS: A cross-sectional study with 38 SCH individuals and 54 EU subjects was performed. They were submitted to Short Form-36 and Chalder questionnaires to evaluate QoL and fatigue, respectively. The tests performed to evaluate muscle function of upper and lower limbs were: maximum quadriceps isometric strength (QS); quadriceps fatigue resistance (T50% QS), QS at 30 seconds (QS30s); quadriceps functional capacity (QFC); maximum isometric handgrip strength (HS); fatigue handgrip resistance (T50% HS), HS at 30 seconds (HS30s); and functional capacity of the shoulder. RESULTS AND CONCLUSIONS: The SCH patients had worse muscle function, regarding HS (25.19 ± 7.00 vs. 30.45 ± 9.98 kgf in EU, P = 0.009) and functional capacity of the shoulder (41.28 ± 48.36 vs. 56.68 ± 37.44 s in EU, P = 0.004). The self-perception of fatigue by Chalder questionnaire (23.91 ± 5.39 vs. 29.77 ± 7.03, P = 0.000) and the QoL in terms of functional capacity (70.20 ± 21.57 vs. 56.25 ± 28.79, P = 0.025), physical aspects (71.42 ± 36.44 vs. 45.83 ± 42.88, P = 0.004), pain (62.48 ± 22.20 vs. 50.05 ± 24.80, P = 0.035), and emotional aspects (70.74 ± 38.26 vs. 46.29 ± 44.56, P = 0.008) were also worse in SCH. In conclusion, the SCH was associated with alterations in the QoL, reduction in the muscle function of upper limbs, and higher degree of fatigue.

Effects of physical activity on body composition and fatigue perception in patients on thyrotropin-suppressive therapy for differentiated thyroid carcinoma.

BACKGROUND: Subclinical thyrotoxicosis (scTox) may be associated with alterations in body composition and fatigue that can be possibly reversed with physical activity. The aim of the present study was to evaluate whether the systematic practice of physical activity improves lower extremity muscle mass and fatigue perception in patients with scTox. MATERIALS AND METHODS: We studied 36 patients (2 men) with median age of 48.0 (43.0-51.0) years, body mass index of 27.4 (22.1-30.2) kg/m(2), thyrotropin <0.4 mU/L, and free thyroxine between 0.8 and 1.9 ng/dL and 48 control subjects (C group; 7 men). Patients were randomly divided in two groups according to the adherence to the exercise training: scTox-Tr (n = 19)-patients who adhered to the exercise intervention and scTox-Sed (n = 17)--patients who did not adhere to it. The C group did not participate in the randomization. The exercise training was supervised by a physical education instructor, and it was composed of 60 minutes of aerobic activity and stretching exercises, twice a week, during 12 weeks. In both groups, body composition was assessed (anthropometric method), and the Chalder Fatigue Scale was determined at baseline and after 3 months of intervention (scTox-Tr group) or observation (scTox-Sed group). RESULTS: At baseline, patients with scTox had lower muscle mass and mid-thigh girth and more fatigue on the Chalder Fatigue Scale than euthyroid control subjects. The scTox-Tr group had an increase in muscle mass, reduction in the variables reflecting whole body fat, and lesser perception of fatigue during the exercise training period (p ≤ 0.05 for these parameters at the start and end of the exercise training period). CONCLUSIONS: scTox is associated with lower muscle mass and mid-thigh girth and more fatigue. Physical activity training can partially ameliorate these characteristics. More studies are needed to determine what training program would be optimum, both in terms of beneficial effects and for avoiding potential adverse responses.