Translation, cross-cultural adaptation, and validation of the french version of the 15-item Myasthenia Gravis Quality Of life scale

Neuromuscular fatigue in autoimmune myasthenia gravis: A cross-sectional study

OBJECTIVES

To investigate the presence of increased neuromuscular fatigue (NMF) in individuals with myasthenia gravis (IwMG), compared to healthy controls. A secondary aim was to assess associations between NMF, strength and perceived health-related quality of life (HRQoL) and symptom severity in IwMG.

METHODS

In this cross-sectional study, we assessed NMF using classical myoelectrical indicators (root mean square: RMS, mean power frequency: MPF) obtained from surface electromyography (sEMG) during a sustained submaximal isometric contraction of the right Biceps Brachii and the right Vastus Lateralis and by evaluating the post-effort decline in peak torque following a fatiguing task consisting of a 40-second sustained isometric contraction. Relationships with MG-specific clinical scores (Myasthenia Muscle Score for symptom severity, MGQOL-15-F for HRQoL) were investigated.

RESULTS

Forty-one females with MG were compared to 18 control females of similar age. IwMG demonstrated reduced strength in both muscle groups, compared to control subjects. In both populations and both limbs, NMF was demonstrated by an increase in RMS and a decrease in MPF. However, IwMG did not demonstrate greater NMF based on these myoelectrical indicators nor based on post-effort peak torque decline.

DISCUSSION

Despite a decrease in baseline strength, IwMG did not display greater NMF in this specific experimental paradigm. This cohort consisted of individuals with mild-to-moderately severe MG which was well-controlled and stable. Further studies are warranted to identify simple and reliable methods to measure NMF in MG and to understand the relationship between NMF and perceived fatigue in activities of daily living for IwMG.

Utilization of MG-ADL in myasthenia gravis clinical research and care

The Myasthenia Gravis Activities of Living (MG‐ADL) scale is an 8‐item patient‐reported scale that measures myasthenia gravis (MG) symptoms and functional status. The objective of the current review is to summarize the psychometric properties of the MG‐ADL and published evidence of MG‐ADL use. A targeted literature review for published studies of the MG‐ADL was conducted using a database and gray literature search. A total of 48 publications and 35 clinical trials were included. Studies indicated that the MG‐ADL is a reliable and valid measure that has been used as an outcome in clinical trials and observational studies to measure MG symptoms and response to treatment. While most often used as a secondary endpoint in clinical trials, its use as a primary endpoint has increased in recent years. The most common MG‐ADL endpoint is change in MG‐ADL score from baseline, although there has been an increase in the analysis of a responder threshold using the MG‐ADL. A new concept of minimal symptom expression (MSE) has emerged more recently. Duration of treatment effect is another important construct that is being increasingly evaluated using the MG‐ADL. The use of the MG‐ADL as a primary endpoint in clinical trials and in responder threshold analyses to indicate treatment improvement has increased in recent years. MSE using the MG‐ADL shows promise in helping to determine success of treatment and may be the aspirational goal of MG treatment for the future once validated, particularly given the evolving treatment landscape in MG.

Validation of Spanish version of 15-item myasthenia gravis quality-of-life questionnaire

OBJECTIVES

The aim of this study was to achieve the translation and cross-cultural adaptation of the MG-QOL15R questionnaire into Spanish and the analysis of its psychometric properties.

MATERIALS AND METHODS

We recruited patients with MG, ≥18 years old, whose mother tongue was Spanish. After the translation and cross-cultural adaptation of the MG-QOL15-R, the following tests were performed: internal consistency using the Cronbach-α coefficient and corrected item-total correlations; reproducibility with a test-retest analysis using intraclass correlation coefficients; and concurrent validity using Spearman's correlation coefficient of the Spanish language MG-QOL15R-S, Myasthenia Gravis Activity of Daily Living (MG-ADL) and Quantitative Myasthenia Gravis (QMG) scores. As an approximation to construct validity, the nonparametric Mann-Whitney U test was performed between MG-QOL15R-S scores according to the Myasthenia Gravis Foundation of America classification.

RESULTS

A total of 83 MG patients were enrolled, mean age 48.19 ± 17.25 years; 58 (69.9%) were women. The mean MG-QOL15R-S score was 11.3 ± 7.1. Cronbach-α coefficient was 0.92. Item-total correlation ranged between 0.43 and 0.75. Intraclass correlation coefficient was 0.80. The Spearman correlation coefficient was 0.637 (p-value < .001) for MG-ADL and 0.487 (p-value < .001) for QMG. Mann-Whitney U tests of the mean MG-QOL15R-S scores were significantly different according to the clinical severity (p-value < .001).

CONCLUSIONS

The Spanish version of the MG-QOL15R is a valid and reliable instrument and potentially useful for measuring health-related quality of life in Spanish-speaking MG patients.

Free-Living Physical Activity and Sedentary Behaviour in Autoimmune Myasthenia Gravis: A Cross-Sectional Study

BACKGROUND

Muscle weakness and fatigability, the prominent symptoms of autoimmune myasthenia gravis (MG), negatively impact daily function and quality of life (QoL). It is currently unclear as to what extent symptoms limit activity and whether physical activity (PA) behaviours are associated with reduced QoL.

OBJECTIVES

This study aimed to describe habitual PA patterns and explore relationships between PA metrics, clinical MG characteristics, and health-related QoL (HRQoL).

METHODS

PA data from a tri-axial trunk accelerometer worn for seven days, was collected from females with generalized, stable MG and compared to control subjects. MG-specific evaluations, the six-minute walk test and knee extension strength were assessed in individuals with MG (IwMG). Mann-Whitney tests were used to study between-group differences. Spearman rank correlation coefficient was performed to explore relationships between variables.

RESULTS

Thirty-three IwMG (mean (SD) age 45 (11) years) and 66 control subjects were included. IwMG perform less vigorous-intensity PA than control subjects (p = 0.001), spend more time sedentary (p = 0.02) and engage in less and shorter durations of moderate-vigorous-intensity PA (MVPA). For IwMG, habitual PA correlated positively with 6 min walking distance (rho = 0.387, p = 0.029) and negatively with body mass index (rho = -0.407, p = 0.019). We did not find any association between PA or sedentary behaviour and; HRQoL, symptom severity nor lower limb strength.

CONCLUSIONS

Individuals with stable MG perform less PA, at lower intensities, and are more inactive than control individuals. Further research is warranted to understand factors influencing PA patterns in MG and whether interventions could be successful in increasing PA quantity and intensity in IwMG.

Home-based exercise in autoimmune myasthenia gravis: A randomized controlled trial

The tolerance of exercise and its effects on quality of life in myasthenia gravis are not currently backed up by strong evidence. The aim of this study was to determine whether exercise as an adjunct therapy is well tolerated and can improve health-related quality of life (HRQoL) in stabilized, generalized autoimmune myasthenia gravis (gMG). We conducted a parallel-group, multi-center prospective RCT using computer-generated block randomization. Adults with stabilized, gMG, and no contra-indication to exercise, were eligible. Participants received usual care alone or usual care and exercise. The exercise intervention consisted of 3-weekly 40 min sessions of an unsupervised, moderate-intensity home rowing program over 3 months. The primary endpoint was the change in HRQoL from randomization to post-intervention. Assessor-blinded secondary endpoints were exercise tolerance and effects on clinical, psychological and immunological status. Of 138 patients screened between October 2014 and July 2017, 45 were randomly assigned to exercise (n = 23) or usual care (n = 20). Although exercise was well tolerated, the intention-to-treat analysis revealed no evidence of improved HRQoL compared to usual care (MGQOL-15-F; mean adjusted between-groups difference of -0.8 points, 95%CI -5.4 to 3.7). Two patients hospitalized for MG exacerbation were from the usual care group.

Measuring Clinical Treatment Response in Myasthenia Gravis

In this article we provide an overview of health-related outcome measurement-to better understand what different outcomes used in myasthenia actually measure-and to provide some guidance when choosing measures based on the clinical context and question. In myasthenia, the most commonly used outcome measures are aimed at assessing the signs and symptoms. In this review, we provide a summary of the most commonly used outcome measures. We discuss instruments that gauge disease overall health impact, such as on disability and quality of life. Finally, we discuss other relevant outcomes such as steroid-sparing effects and the role of surrogate markers.

EQ-5D-5L and SF-6D health utility index scores in patients with myasthenia gravis

BACKGROUND AND PURPOSE

Health utilities are a preference-based method of valuing health states that are used in healthcare research, such as economic evaluations. There are limited health utility valuation data for patients with myasthenia gravis (MG). The aim of the study was to describe health utilities for patients with MG and different health states, using the EQ-5D-5L and SF-6D utility instruments, and to explore clinical and demographic determinants of utilities in this population.

METHODS

Patients completed the EQ-5D-5L and SF-6D. In addition, patients were assessed with the Myasthenia Gravis Foundation of America classification, Myasthenia Gravis Impairment Index and MG-QOL15 as disease-specific measures, and the Neuro-QoL Fatigue scale. We calculated mean utilities for each Myasthenia Gravis Foundation of America severity class. We built regression models for the EQ-5D-5L and SF-6D to determine the clinical and demographic factors that determine patients' valuation of their health state.

RESULTS

Among 254 patients, mean EQ-5D-5L health utilities were as follows: Remission, 0.94 ± 0.03; Minimal Manifestations, 0.92 ± 0.04; Class I, 0.89 ± 0.06; Class II, 0.78 ± 0.16; Class III, 0.58 ± 0.24 and Class IV, 0.61 ± 0.22. Mean SF-6D health utilities were as follows: Remission, 0.83 ± 0.07; Minimal Manifestations, 0.86 ± 0.14; Class I, 0.82 ± 0.14; Class II, 0.67 ± 0.12; Class III, 0.56 ± 0.11 and Class IV, 0.50 ± 0.10. The limb/axial scores were more highly correlated to health utilities than ocular or bulbar scores.

CONCLUSIONS

We present estimates of health utilities for patients with MG that can be used in cost-utility and decision analyses. Limb/axial symptoms had a higher impact on health utilities than ocular or bulbar symptoms, which might reflect the impact of mobility on health valuation.

Translation, cross-cultural adaptation, and validation of the chinese version of the 15-item myasthenia gravis quality of life questionnaire

INTRODUCTION

We sought to translate, cross-culturally adapt, and evaluate the internal consistency and validity of the Chinese version of the 15-Item Myasthenia Gravis Quality of Life (MG-QOL15).

METHODS

Translation and cross-cultural adaptation of the MG-QOL15 were performed. We used Cronbach's α to test internal consistency, one-way analysis of variance to test construct validity, and Pearson or Spearman correlations to test discriminant and concurrent validity.

RESULTS

We enrolled 168 outpatients. Internal consistency was excellent (Cronbach's α = 0.928). The MG-QOL15 discriminated MG severity as stratified by the MG Composite (MGC; P < 0.001) and Osserman class (P = 0.01). Concurrent validity was low to moderate with the subscales of the 36-item Short Form (-0.31 to ∼-0.59), MGC (r = 0.46), and Myasthenia Gravis Activities of Daily Living profile (r = 0.54).

DISCUSSION

The Chinese MG-QOL15 showed comparable construct, discriminant and concurrent validity, and internal consistency with to the original version. Muscle Nerve 59:95-99, 2019.

The benefits and tolerance of exercise in myasthenia gravis (MGEX): study protocol for a randomised controlled trial

BACKGROUND

Research exploring the effects of physical exercise in auto-immune myasthenia gravis (MG) is scarce. The few existing studies present methodological shortcomings limiting the conclusions and generalisability of results. It is hypothesised that exercise could have positive physical, psychological as well as immunomodulatory effects and may be a beneficial addition to current pharmacological management of this chronic disease. The aim of this study is to evaluate the benefits on perceived quality of life (QOL) and physical fitness of a home-based physical exercise program compared to usual care, for patients with stabilised, generalised auto-immune MG.

METHODS

MGEX is a multi-centre, interventional, randomised, single-blind, two-arm parallel group, controlled trial. Forty-two patients will be recruited, aged 18-70 years. Following a three-month observation period, patients will be randomised into a control or experimental group. The experimental group will undertake a 40-min home-based physical exercise program using a rowing machine, three times a week for three months, as an add-on to usual care. The control group will receive usual care with no additional treatment. All patients will be followed up for a further three months. The primary outcome is the mean change in MGQOL-15-F score between three and six months (i.e. pre-intervention and immediately post-intervention periods). The MGQOL-15-F is an MG-specific patient-reported QOL questionnaire. Secondary outcomes include the evaluation of deficits and functional limitations via MG-specific clinical scores (Myasthenia Muscle Score and MG-Activities of Daily Living scale), muscle force and fatigue, respiratory function, free-living physical activity as well as evaluations of anxiety, depression, self-esteem and overall QOL with the WHO-QOL BREF questionnaire. Exercise workload will be assessed as well as multiple safety measures (ECG, biological markers, medication type and dosage and any disease exacerbation or crisis).

DISCUSSION

This is the largest randomised controlled trial to date evaluating the benefits and tolerance of physical exercise in this patient population. The comprehensive evaluations using standardised outcome measures should provide much awaited information for both patients and the scientific community. This study is ongoing.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02066519 . Registered on 13 January 2014.