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

Generalized myasthenia gravis with acetylcholine receptor antibodies: A guidance for treatment

BACKGROUND

Generalized myasthenia gravis (MG) with antibodies against the acetylcholine receptor is a chronic disease causing muscle weakness. Access to novel treatments warrants authoritative treatment recommendations. The Nordic countries have similar, comprehensive health systems, mandatory health registers, and extensive MG research.

METHODS

MG experts and patient representatives from the five Nordic countries formed a working group to prepare treatment guidance for MG based on a systematic literature search and consensus meetings.

RESULTS

Pyridostigmine represents the first-line symptomatic treatment, while ambenonium and beta adrenergic agonists are second-line options. Early thymectomy should be undertaken if a thymoma, and in non-thymoma patients up to the age of 50-65 years if not obtaining remission on symptomatic treatment. Most patients need immunosuppressive drug treatment. Combining corticosteroids at the lowest possible dose with azathioprine is recommended, rituximab being an alternative first-line option. Mycophenolate, methotrexate, and tacrolimus represent second-line immunosuppression. Plasma exchange and intravenous immunoglobulin are used for myasthenic crises and acute exacerbations. Novel complement inhibitors and FcRn blockers are effective and fast-acting treatments with promising safety profiles. Their use depends on local availability, refunding policies, and cost-benefit analyses. Adapted physical training is recommended. Planning of pregnancies with optimal treatment, information, and awareness of neonatal MG is necessary. Social support and adaptation of work and daily life activities are recommended.

CONCLUSIONS

Successful treatment of MG rests on timely combination of different interventions. Due to spontaneous disease fluctuations, comorbidities, and changes in life conditions, regular long-term specialized follow-up is needed. Most patients do reasonably well but there is room for further improvement. Novel treatments are promising, though subject to restricted access due to costs.

Current state of research on exercise for the treatment of myasthenia gravis: A scoping review

OBJECTIVE

To provide a comprehensive overview of existing evidence, research gaps, and future research priorities concerning the treatment of myasthenia gravis (MG) using exercise therapies.

METHOD

Clinical studies on exercise treatment for MG were searched in nine databases to conduct a scoping review. Two independent researchers screened the literature and comprehensively analyzed the characteristics and limitations of the included articles.

RESULTS

A total of 5725 studies were retrieved, of which 24 were included. The included studies were conducted in 16 different countries/regions and 456 patients were enrolled. Study designs included both interventional and observational studies. Exercise interventions included aerobic exercise, resistance exercise, balance training, and stretch training, and are typically administered in conjunction with medication, usual care, or some other interventions. The intensity, frequency, and duration of exercise interventions varied hugely among studies. Six-minute walk test, adverse events, muscle strength, MG quality of life-15 scale, forced vital capacity, quantitative MG scale, and MG activities of daily living scale were the most frequently used outcomes. All studies reported results in favor of the efficacy and safety of exercise in MG, and exercise-related adverse events were reported in two studies.

CONCLUSION

This scoping review provides an overview of the evidence concerning exercise treatment for MG. Key gaps in evidence include a limited number of participants, complex interventions, variability in outcome selection, and insufficient reporting in publications. The promotion of exercise treatment for MG still encounters several obstacles. A larger population, rigorous study design and conduction, standardized interventions and outcomes, and standardized reporting are essential.

Perspectives of people with myasthenia gravis on physical activity and experience of physical activity advice from health professionals in the Australian context: a qualitative study

PURPOSE

Physical activity is an important modifiable determinant of health. There has been a historical aversion to movement in people with myasthenia gravis (MG) due to the pathophysiology of the disease, however, research suggests engagement in physical activity is safe and does not exacerbate symptoms. There are currently no studies investigating the qualitative perspectives of people with MG on physical activity. The aim of this study was to explore perceptions of physical activity, barriers, enablers, and participants' experiences of physical activity advice from health professionals.

MATERIALS AND METHODS

Semi-structured interviews were used, with verbatim transcripts analysed using content analysis.

RESULTS

Ten adults (median age 64.5 years) living in Australia with generalised MG were interviewed. Key findings were identified: (1) Physical activity is perceived to be important for general health and for MG; (2) Medical management and social support are key enablers; (3) Fatigue and pain are potential barriers; and (4) Experiences with healthcare professionals were considered insufficient and failed to provide disease specific advice regarding MG and physical activity.

CONCLUSION

People with MG have unique barriers and enablers to physical activity engagement that clinicians should consider when providing physical activity behaviour change support to this population.

Systematic review of the patient burden of generalised myasthenia gravis in Europe, the Middle East, and Africa

BACKGROUND

Myasthenia gravis (MG) is a rare autoimmune disease characterised by muscle weakness, and progression from ocular (oMG) to generalised (gMG) symptoms results in a substantial negative impact on quality of life (QoL). This systematic review aimed to provide an overview of the patient burden experienced by people living with gMG.

METHODS

Electronic database searches (conducted March 2022), supplemented by interrogation of grey literature, were conducted to identify studies reporting patient burden outcomes in patients with gMG in Europe, the Middle East and Africa. Results were synthesised narratively due to the heterogeneity across trials.

RESULTS

In total, 39 patient burden publications (representing 38 unique studies) were identified as relevant for inclusion in the systematic review, consisting of 37 publications reporting formal patient-reported outcome measures (PROMs), and two publications describing alternative qualitative assessments of patient experience. The studies included a variety of measures including generic and disease-specific PROMs, as well as symptom-specific PROMs focusing on key comorbidities including depression, anxiety, fatigue and sleep disturbance. The findings showed some variation across studies and PROMs; however, in general there was evidence for worse QoL in patients with gMG than in healthy controls or in patients with oMG, and a trend for worsening QoL with increasing MG severity.

CONCLUSIONS

This review highlights the importance of considering patient QoL when developing and assessing treatment and management plans for patients with gMG. However, the heterogeneity identified across studies illustrates the need for further representative and well-powered studies in large cohorts administering consistent, validated questionnaires.

TRIAL REGISTRATION

The protocol for this systematic review was registered in PROSPERO: CRD42022328444.

Genetically predicted effects of physical activity and sedentary behavior on myasthenia gravis: evidence from mendelian randomization study

BACKGROUND

Myasthenia gravis (MG) is an autoimmune disorder affecting the neuromuscular junction. Despite the potential benefits of higher physical activity and lower sedentary behavior in MG patients, evidence from observational studies for the effect of physical activity on the risk of MG is limited and inconclusive.

METHODS

We employed linkage disequilibrium score (LDSC) regression, two-sample Mendelian randomization (MR), and its multivariable extension analyses (MVMR) to assess the relationship between leisure screen time (LST), moderate-to-vigorous intensity physical activity during leisure time (MVPA) and the risk of MG using genome-wide association studies (GWAS) summary datasets. MR analyses were performed using the inverse-variance-weighted (IVW), weighted-median, and MR-Egger regression. Sensitivity analyses were further performed using alternative instruments to test the robustness of our findings.

RESULTS

We found evidence of genetic overlap between LST (rg = 0.113, P = 0.023) and MG, as well as between MVPA (rg=-0.220, P = 0.0001) and MG, using LDSC method. The results of the MR suggested an association between genetic liability to LST and increased risk of MG (IVW OR = 1.609, 95% CI = 1.153 to 2.244; P = 0.005). This association was particularly notable for late-onset MG (IVW OR = 1.698, 95% CI = 1.145 to 2.518; P = 0.008), but not for early-onset MG. Consistent findings were obtained in the MVMR analysis using BMI as covariate (IVW OR = 1.593, 95% CI 1.167 to 2.173, P = 0.003). However, the MR analysis does not support a substantial causal effect of MVPA on the risk of MG.

CONCLUSION

Our findings support a causal effect of sedentary behavior as measured by LST on MG, indicating that lack of exercise may play a role in the development of MG. Longitudinal and interventional studies of this association are warranted.

The use of digital outcome measures in clinical trials in rare neurological diseases: a systematic literature review

Developing drugs for rare diseases is challenging, and the precision and objectivity of outcome measures is critical to this process. In recent years, a number of technologies have increasingly been used for remote monitoring of patient health. We report a systematic literature review that aims to summarize the current state of progress with regard to the use of digital outcome measures for real-life motor function assessment of patients with rare neurological diseases. Our search of published literature identified 3826 records, of which 139 were included across 27 different diseases. This review shows that use of digital outcome measures for motor function outside a clinical setting is feasible and employed in a broad range of diseases, although we found few outcome measures that have been robustly validated and adopted as endpoints in clinical trials. Future research should focus on validation of devices, variables, and algorithms to allow for regulatory qualification and widespread adoption.

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.

Implementation of tailored exercise programs for MG patients in a gym setting: a pragmatic feasibility case study

Although supervised aerobic and resistance training in a hospital setting was proven safe and beneficial for well-controlled myasthenia gravis (MG) patients, implementation of similar programs in the community has not been studied. We conducted a pragmatic open-label study at a large gym in Uppsala, Sweden. Seven patients with generalized MG were recruited to participate in an individualized, tailored exercise program, based on individual baseline status and personal goals, with a personal trainer. All patients completed the entire training period. The individually tailored exercise program was implemented safely and effectively, with all patients improving in aerobic capacity, muscle strength, and balance. Our pragmatic open-label case study suggests that well-controlled patients with generalized MG can extend their physical exercise to personal training in the gym. This is an essential step towards reducing the barriers to implementing exercise procols and increasing the availability of these interventions to MG patients.

Physical Activity and Sedentary Behaviour in People with Myasthenia Gravis: A Cross-Sectional Study

BACKGROUND

Despite improvements in the medical management of myasthenia gravis (MG) in recent years, patients continue to report poor health and wellbeing outcomes such as high levels of fatigue, reduced quality of life (QoL), walking limitation and lowered balance confidence. Physical activity has been shown to be associated with these outcomes in other populations, however, there has been limited research in adults with MG.

OBJECTIVE

To describe physical activity and sedentary behaviour in adults with MG and to explore associations between these behaviours and fatigue, QoL, balance confidence and walking limitation.

METHODS

A self-report online survey was used to assess physical activity, sedentary behaviour, fatigue, QoL, balance confidence and walking limitation in adults with MG. Multiple linear regression was used to examine associations and descriptive statistics were used to analyse participant characteristics, physical activity, and sedentary behaviour.

RESULTS

Eighty-five adults with MG were included (mean age 48±16 years). Over half of participants (n = 53, 62.4%) reported sufficient physical activity to meet public health guidelines. Participants reported an average of 9 h/day of sedentary time (mean 9.0±3.5). Physical activity and fatigue (R2 = 0.196), QoL (R2 = 0.330), walking limitation (R2 = 0.305) and balance confidence (R2 = 0.304) were significantly (p <  0.05) and positively correlated, with no associations found for sedentary behaviour. When patterns of physical activity and sedentary behaviour were combined, lower fatigue (R2 = 0.213), higher QoL (R2 = 0.364), reduced walking limitation (R2 = 0.341) and higher balance confidence (R2 = 0.279) was observed in patients who had greater physical activity levels (>  150 mins/week) and lower sedentary time (<  10 h/day).

CONCLUSIONS

Higher physical activity and lower sedentary behaviour is associated with favorable health and wellbeing outcomes in adults with MG. Further research is required to ascertain whether these behaviours may be an appropriate target intervention to improve outcomes in this population.