Muscle dysfunction is associated with poorer health-related quality of life in adults with sickle cell anaemia.

BACKGROUND: It is known that episodes of microvascular obstruction and oxidative stress in sickle cell anaemia (SCA) can damage muscle tissue. As a consequence, deterioration in muscle function may potentially contribute to poor health-related quality of life (HRQoL) in subjects with SCA, particularly those who do not use long-term treatment. OBJECTIVES: To evaluate muscle function in adults with SCA, to study the correlations between muscle function and HRQoL and to analyse the impact of hydroxyurea treatment. METHODS: Twenty-two adults with SCA and 20 matched controls were subjected to Short Form-36 (SF-36), respiratory muscle strength measurement, isometric hand grip strength (iHGS) measurement and knee isokinetic dynamometry. RESULTS: In relation to their healthy peers, adults with SCA had lower SF-36 scores, respiratory muscle strength and iHGS. Regarding the isokinetic test, adults with SCA showed lower values, especially in the variables measured in flexion and with an angular velocity of 240∘/s. There was a significant correlation between the peak torque (PT) at 240∘/s and the physical component summary (SF-36PCS) in both extension (r= 0.77; p< 0.001) and flexion (r= 0.82; p< 0.001). Significant correlations were also observed between the agonist/antagonist ratio at 240∘/s and the SF-36PCS (r= 0.50; p< 0.001). The use of hydroxyurea led to higher scores on the SF-36 and higher values in knee isokinetic dynamometry. CONCLUSIONS: Adults with SCA have muscle dysfunction, especially with regard to endurance of the knee flexor muscles. In these patients, there is a significant association between muscle function and HRQoL. Moreover, the use of hydroxyurea is associated with better HRQoL and less muscle dysfunction.

Muscle function in women with systemic sclerosis: Association with fatigue and general physical function.

BACKGROUND: Individuals with systemic sclerosis have muscle functions with varying degrees of muscle weakness and atrophy, which in turn can have a negative impact on functional and health-related quality of life. This study aimed to evaluate peripheral muscle performance using isokinetic dynamometry of the knee in women with systemic sclerosis and to correlate peripheral muscle dysfunction with disability levels and general fatigue. METHODS: Twenty-six women with systemic sclerosis and a matched control group with an equal number of women underwent knee isokinetic dynamometry at angular speeds of 75°/s and 240°/s, isometric handgrip strength, the Health Assessment Questionnaire Disability Index, the Functional Assessment of Chronic Illness Therapy-Fatigue scale, and the Fatigue Impact Scale. FINDINGS: Women with systemic sclerosis showed significant reductions in almost all isokinetic parameters for the two angular velocities tested compared with the controls. An agonist/antagonist ratio with values <40% was observed in approximately one-third of the patients. These patients had lower isometric handgrip strength. These patients also performed worse on the two general fatigue scales evaluated. Significant correlations were observed between the isokinetic parameters and the measured isometric handgrip strength, and the Health Assessment Questionnaire Disability Index. INTERPRETATION: Systemic sclerosis patients have reduced strength and endurance as well as a muscle imbalance between the quadriceps and hamstrings. In these patients, lower muscle dysfunction of the knee joint is associated with lower handgrip strength and physical incapacity.

Balance Control and Peripheral Muscle Function in Aging: A Comparison Between Individuals with Acromegaly and Healthy Subjects.

Advances in the knowledge of acromegaly are leading to an increase in the survival rate of acromegalic subjects. This study was conducted to evaluate balance control, risk of falls, and peripheral muscle function in acromegalic older adults. Seventeen older subjects with acromegaly (67 [63-73] years) and 20 paired control subjects were evaluated with balance scales, force platform, and knee isokinetic dynamometry tests. There were significant differences between the groups on several balance and gait scales, with a worse performance and greater risk of falls in the acromegalic older adults. Acromegalic older adults had lower values for peak torque, maximum repetition of the total work, and total work during extension at 240°/s. The acromegalic older adults had higher values in the medial-lateral range. Acromegaly subjects had lateral instability that compromises their body balance and increases the risk of falls. Moreover, there was a propensity for muscle fatigue in these individuals.

Explanatory models of muscle performance in acromegaly patients evaluated by knee isokinetic dynamometry: Implications for rehabilitation.

PURPOSE: To evaluate the effects of demographics and hormonal variations on knee muscle performance in patients with acromegaly and develop explanatory models of peripheral muscle function in these individuals. METHODS: This was a cross-sectional study in which 53 acromegalics and 27 healthy subjects underwent knee isokinetic dynamometry to evaluate the peak torque value for leg extension at 75°/s (PTE75) and 240°/s (PTE240). Separate multivariable linear regression models for the prediction of PTE75 and PTE240 were tested using variables commonly used as predictors in the clinical setting and other specific variables related to acromegaly. RESULTS: The final prediction model for PTE75 (R(2)=0.888; adjusted R(2)=0.820, SE of bias=16.2Nm, p<0.001) was -0.221×growth hormone+36.791×sexmale=1-27.407×statusactive=1-0.690×age+148.071. The final prediction model for PTE240 (R(2)=0.816; adjusted R(2)=0.805, SE of bias=8.8Nm, p<0.001) was -0.174×growth hormone+12.522×sexmale=1-0.520×age+98.099. CONCLUSIONS: In acromegalics, high growth hormone levels, female gender, and older age are associated with reduced muscle strength and endurance. Additionally, active disease negatively affects peripheral muscle strength in these patients.