Evaluation of quadriceps and hamstring muscle function through isokinetic dynamometry in patients with active and controlled acromegaly

Abstract

Introduction: Acromegaly is a chronic and rare endocrine disease resulting from excessive production of growth hormone (GH) and growth factor similar to insulin type I. Studies show that acromegaly patients have lower peripheral muscle strength and increased fatigability, so it becomes essential one more comprehensive assessment of muscle function and the impact of fatigue on quality of life of these individuals. Objectives: The aim of this study was to establish a functional profile on strength and peripheral muscle strength in patients with acromegaly. As specific objectives, we sought to: (1) compare the peripheral muscle strength of the lower limbs and upper limbs, physical activity, quality of life and impact of fatigue among acromegaly patients and healthy subjects; (2) correlate the peripheral muscle strength of the lower limbs and upper limbs with the level of physical activity, quality of life and impact of fatigue in patients with acromegaly; (3) compare the active disease with controlled disease and to the peripheral muscles functionality; and (4) comparing the active disease with controlled disease and the level of physical activity, quality of life and impact of fatigue. Methods: Thirteen patients with active disease, 20 patients with controlled disease, and 21 healthy controls matched by age, gender, weight, height, and body mass index underwent knee isokinetic dynamometry at 75º/s and 240º/s angular velocity as well as isometric dynamometry to assess handgrip strength. The serum GH (growth hormone) and insulin-like growth factor I levels of all acromegalics were measured, and the subjects were also assessed by the International Physical Activity Questionnaire (IPAQ) Short Form, the Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) scale, the Fatigue Impact Scale (FIS), and the Acromegaly Quality of Life Questionnaire (AcroQoL). Results: Compared to the healthy controls, the acromegalics exhibited significant reductions in the peak torque, maximum work repetition, and total work for both extension and flexion at both angular velocities. The agonist/antagonist ratio at 75º/s was lower in individuals with active acromegaly than in patients with controlled acromegaly and healthy controls [46 (38–53) vs. 55 (49–64) vs. 65 (60–68), p = 0.0002]. Compared to controls, the patients also exhibited decreased handgrip strength values and FACIT-F scores and increased FIS scores. There were significant correlations between the measures obtained by isokinetic dynamometry and GH levels, handgrip strength values, and scores on the general fatigue questionnaires, but not for the AcroQoL scores. Conclusion: These findings show that acromegalics exhibit decreased muscle performance in the upper and lower limbs, as well as excessive imbalances between the peak torque of the hamstrings and quadriceps. In addition, poorer muscle performance is associated with higher levels of GH and increased general fatigue.