Diversity in mental fatigue and social profile of patients with myasthenia gravis in two different Northern European countries

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.

Personality factors in patients with myasthenia gravis: A prospective study

INTRODUCTION

In myasthenia gravis (MG), depression and anxiety have frequently been reported as comorbidities. However, little is known about personality characteristics in MG patients. We aimed to characterise personality traits in MG and to correlate them with disease severity and disease course.

METHODS

The Big Five Inventory data questionnaire was used to investigate personality traits in 44 MG patients and 45 healthy controls similar in age and gender. In 28 MG patients, a caregiver was also available for patient assessments to limit bias associated with social desirability in patients' responses. Patients were assessed with regard to premorbid personality (before manifestation of MG) and to present condition. In addition, anxiety and depression scales (Hospital Anxiety and Depression Scale and Beck Anxiety Inventory) were applied.

RESULTS

Compared to controls, MG patients showed significantly higher levels of neuroticism, whereas openness and extraversion were significantly lower. Agreeableness and conscientiousness did not differ between groups. Neuroticism was influenced by disease severity such as generalization of weakness, presence of thymoma, and bulbar involvement as well as disease duration. Neuroticism correlated with premorbid level of neuroticism but also with depression and anxiety scores.

CONCLUSION

A personality profile of increased neuroticism and lower openness and extraversion in MG patients may contribute considerably to the perception of disease severity. It may also be related to frequent comorbidities such as anxiety and depression. Although premorbid levels of neuroticism were increased, this characteristic may also increase considerably during the course of the disease. The data indicate that muscle weakness in MG is accompanied or even complicated by psychological aspects. Therefore, a psychological and behavioral intervention in addition to the specific pharmacological therapy might be of particular value.

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.

Adult-Onset Neuroepidemiology in Finland: Lessons to Learn and Work to Do

Finland is a relatively small genetic isolate with a genetically non-homogenous population. Available Finnish data on neuroepidemiology of adult-onset disorders are limited, and this paper describes the conclusions that can be drawn and their implications. Apparently, Finnish people have a (relatively) high risk of developing Unverricht-Lundborg disease (EPM1), Multiple Sclerosis (MS), Amyotrophic Lateral Sclerosis (ALS), Spinal muscular atrophy, Jokela type (SMAJ) and adult-onset dystonia. On the other hand, some disorders, such as Friedreich's ataxia (FRDA) and Wilson's disease (WD), are almost absent or completely absent in the population. Valid and timely data concerning even many common disorders, such as stroke, migraine, neuropathy, Alzheimer's disease and Parkinson's disease, are unavailable, and there are virtually no data on many less-common neurological disorders, such as neurosarcoidosis or autoimmune encephalitides. There also appear to be marked regional differences in the incidence and prevalence of many diseases, suggesting that non-granular nationwide data may be misleading in many cases. Concentrated efforts to advance neuroepidemiological research in the country would be of clinical, administrative and scientific benefit, but currently, all progress is blocked by administrative and financial obstacles.

Dissecting the fatigue experience: A scoping review of fatigue definitions, dimensions, and measures in non-oncologic medical conditions

Introduction

Fatigue is a prevalent and potentially debilitating symptom that impacts the health-related quality-of-life of individuals diagnosed with acute and chronic medical conditions. Yet, its etiologic mechanism is not fully understood. Additionally, the assessment and determination of the clinical meaning of fatigue and its multidimensionality may vary by medical condition.

Methods

A scoping literature review was conducted to investigate how fatigue is defined and measured, including its dimensions, in non-oncologic medical conditions. The PubMed database was searched using keywords.

Results

Overall, 8376 articles were screened at the title/abstract levels, where 293 articles were chosen for full-text review that mentioned fatigue or included fatigue measures. The review of the full text excluded 246 articles that did not assess at least one fatigue dimension using validated questionnaires and clinical tests. The final set included 47 articles. Physical fatigue was the most assessed fatigue dimension and the Multidimensional Fatigue Inventory was the most widely used questionnaire to assess fatigue in this review.

Limitations

This review was limited by including only English-language publications and using PubMed as the sole database for the search.

Conclusions

This review affirms that fatigue is a multidimensional construct, agnostic of medical condition, and that individual fatigue dimensions can be measured by validated clinical measures. Future research should focus on expanding the repertoire of clinical measures to assess specific fatigue dimensions.

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The 27 different validated clinical measures used to assess fatigue and its dimensions; 20 instruments assessed the physical, 8 for mental, 7 cognitive, 5 for motivational, 2 for emotional, 1 peripheral, 1 for central, 1 psychosocial.

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Physical was the most measured dimension, as assessed in 42 of 47 included articles.

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This review affirms that fatigue is a multidimensional construct, agnostic of medical condition, and that individual fatigue dimensions can be measured by validate clinical measures.

Peripheral blood hsa-circRNA5333-4: A novel biomarker for myasthenia gravis

In this study, the potential of specific Circular RNAs (circRNAs) as novel peripheral blood biomarkers for myasthenia gravis (MG) was explored. We analyzed circRNAs in the peripheral blood of three normal controls and three MG patients using RNA microarray. Candidate circRNAs were validated in three independent cohorts by Quantitative Real-time polymerase chain reaction (qPCR). Eleven differentially expressed circRNAs were initially identified and four were confirmed in the first independent cohort. Hsa_circ_0076490 and hsa-circ_5333-4 had the largest areas under the curve (AUCs) of the receiver operating characteristics (ROC) and were validated in the second cohort. In the third cohort, hsa-circRNA5333-4 had a larger AUC: 0.864 (95% confidence interval [CI] = 0.801-0.928, P < 0.001), a stronger correlation with the Quantitative Myasthenia Gravis Score (qMG): r = 0.505 (P < 0.001) and was correlated with gender and acetylcholine receptor antibody levels (P < 0.05). So hsa-circRNA5333-4 represents a novel biomarker for the diagnosis and monitoring of MG.

Circulating miRNAs as Potential Biomarkers in Myasthenia Gravis: Tools for Personalized Medicine

Myasthenia gravis (MG) is an autoimmune disease caused by antibodies which attack receptors at the neuromuscular junction. One of the main difficulties in predicting the clinical course of MG is the heterogeneity of the disease, where disease progression differs greatly depending on the subgroup that the patient is classified into. MG subgroups are classified according to: age of onset [early-onset MG (EOMG; onset ≤ 50 years) versus late-onset MG (LOMG; onset > 50 years]; the presence of a thymoma (thymoma-associated MG); antibody subtype [acetylcholine receptor antibody seropositive (AChR+) and muscle-specific tyrosine kinase antibody seropositive (MuSK+)]; as well as clinical subtypes (ocular versus generalized MG). The diagnostic tests for MG, such as antibody titers, neurophysiological tests, and objective clinical fatigue score, do not necessarily reflect disease progression. Hence, there is a great need for reliable objective biomarkers in MG to follow the disease course as well as the individualized response to therapy toward personalized medicine. In this regard, circulating microRNAs (miRNAs) have emerged as promising potential biomarkers due to their accessibility in body fluids and unique profiles in different diseases, including autoimmune disorders. Several studies on circulating miRNAs in MG subtypes have revealed specific miRNA profiles in patients’ sera. In generalized AChR+ EOMG, miR-150-5p and miR-21-5p are the most elevated miRNAs, with lower levels observed upon treatment with immunosuppression and thymectomy. In AChR+ generalized LOMG, the miR-150-5p, miR-21-5p, and miR-30e-5p levels are elevated and decrease in accordance with the clinical response after immunosuppression. In ocular MG, higher levels of miR-30e-5p discriminate patients who will later generalize from those remaining ocular. In contrast, in MuSK+ MG, the levels of the let-7 miRNA family members are elevated. Studies of circulating miRNA profiles in Lrp4 or agrin antibody-seropositive MG are still lacking. This review summarizes the present knowledge of circulating miRNAs in different subgroups of MG.

miR-30e-5p as predictor of generalization in ocular myasthenia gravis

Objective

To determine a predictive factor for the risk of conversion from ocular myasthenia gravis (OMG) to generalized MG (GMG) in a prospective study.

Methods

RNA was isolated from serum samples and detection of microRNA (miRNA) expression analyzed with qPCR. In the discovery set, 179 human miRNAs were assayed for profiling of five OMG patients and four age‐ and gender‐matched healthy controls. Based on the specific accumulation pattern of 19 miRNAs from the discovery set, in addition to miRNAs previously found elevated in generalized MG (GMG; miR‐150‐5p and miR‐30e‐5p), 21 miRNAs were subsequently analyzed in a validation cohort of 83 OMG patients (82 immunosuppression treatment naive; 49 male) within 3 months of diagnosis and at a follow‐up visit (median duration 28 months from first visit).

Results

Thirteen patients generalized 14.8 ± 12.0 months after the diagnosis and the majority (85%) belonged to the late onset MG group. Two miRNAs were significantly higher in secondary GMG (SGMG) patients compared to OMG patients with late onset MG: miR‐30e‐5p (9.1 ± 0.5 vs. 6.3 ± 0.9; P < 0.0001) and miR‐150‐5p (7.4 ± 1.1 vs. 6.4 ± 1.1; P = 0.01). The sensitivity for miR‐30e‐5p in differentiating OMG and SGMG was 96% in all OMG patients and 100% in late onset OMG patients.

Interpretation

This is the first study to describe a potential predictive factor associated with the risk of generalization for patients with OMG. Raised levels (>8) of miR‐30e‐5p at initial presentation in patients with ocular MG symptoms, give a predictive cut‐off for subsequent generalization of 96–100%.

Lifestyle factors and disease-specific differences in subgroups of Swedish Myasthenia Gravis

PURPOSE

To evaluate disease-specific differences between Myasthenia Gravis (MG) subgroups and compare patterns of lifestyle between MG patients and population controls.

METHODS

All MG patients (n = 70) in Jönköping County, Sweden, were invited to answer a disease-specific questionnaire, containing questions about disease-specific data, lifestyle, comorbidity, and mental fatigue. The patients were clinically evaluated. Four hundred age- and gender-matched population controls were invited to answer the nondisease-specific part of the questionnaire. Disease-specific issues were compared between MG subgroups. Lifestyle-related factors and concomitant conditions were compared to the population controls.

RESULTS

Forty MG patients and 188 population controls participated in the study. In the late-onset MG (LOMG; N = 18) subgroup, the male predominance was higher than previously reported. In the early-onset MG (EOMG; N = 17) subgroup, time to diagnosis was longer, fatigue was higher, and bulbar weakness was the dominant symptom (65%). Compared to their matched population controls, LOMG patients were more obese (OR = 13.7, P = 0.015), ate less fish (OR = 4.1, P = 0.012), tended to smoke more (OR = 4.1, P = 0.086), and tended to be employed as manual laborers more often (OR = 2.82, P = 0.083). Mental health problems and sickness benefits were more common among MG patients than in controls, and MG patients were less regularly doing focused physical activity.

CONCLUSIONS

It is important to consider disease-specific differences when tailoring the management of individual MG patients. There is a need for improved knowledge on how to apply primary and secondary prevention measures to lifestyle disorders in MG patients without risk of deterioration.

A Physical and Psychological Approach to Managing Fatigue in Myasthenia Gravis: A Pilot Study

BackgroundFatigue in myasthenia gravis (MG) is common and difficult to manage. Unlike myasthenic weakness it is not amenable to drug therapies.ObjectiveOur primary aim was to investigate whether a combination of physical and psychological therapy would help address symptoms of fatigue in MG patients, who have stable disease but residual problematic fatigue. Our secondary aim was to quantitate fatigue by applying different scores and to ascertain which would be most relevant to apply in MG.MethodsWe recruited 10 MG patients with stable disease and who suffer from fatigue. Nine of these 10 patients participated in a 10-week program that involved physical and psychological intervention. We quantified their fatigue using the modified fatigue impact scale (MFIS), the visual analogue fatigue scale (VAFS) and the fatigue severity scale (FSS) at the start of the study, at various intervals during the program and 3 months later.ResultsDuring the program, there was a small improvement in the physical and psychosocial subscale of the MFIS. There was a significant improvement (p < 0.01) in the VAFS at the end of the program. No clear improvement was noted in FSS. Three months later, all fatigue scores declined to baseline but 50% of patients had made some life-style changes.ConclusionsThis is a small pilot study, which utilized a combined approach with physical and psychological therapy, and showed some benefit in improving fatigue in patients with MG. The improvement was small and unsustained. Because of the small patient cohort, one cannot derive any firm conclusions and a larger study is required to investigate this further.

Diversity in mental fatigue and social profile of patients with myasthenia gravis in two different Northern European countries

Self-estimated health can be used for comparison of different diseases between countries. It is important to elaborate on whether disparities in self-estimated health are due to disease-specific parameters or socioeconomic differences. In this study, we aimed at evaluating clinical and social similarities and differences in myasthenia gravis (MG) patients between comparable regions in two Baltic Sea countries, Estonia and Sweden.

METHODS

This cross-sectional study included southern counties in Sweden and Estonia of comparable size. All patients with a confirmed MG diagnosis were asked to answer two questionnaires including demographic and disease-specific data, lifestyle issues, and mental fatigue (Fatigue Severity Scale [FSS]). Clinical fatigue was assessed objectively through the Quantitative Myasthenia Gravis Score (QMG).

RESULTS

Thirty-six of 92 identified patients in Estonia and 40 of 70 identified MG patients in Sweden chose to participate in the study. The demographic characteristics and symptoms reported by the patients were similar. QMG score did not differ; however, the Estonian patients scored their current subjective disease severity significantly higher (5.6 ± 2.8) compared to the Swedish patients (3.4 ± 2.3, p = .0005). Estonian patients also had significantly higher FSS scores (5.0 ± 1.7) than Swedish patients (3.5 ± 1.6; p = .001). Swedish patients were more active and performed physical activity more regularly (29.1% in Estonia and 74.2% in Sweden, p = .004).

CONCLUSIONS

Although, the patients had comparable clinical fatigue, Estonian patients evaluated their health state as being more severe and reported more mental fatigue than Swedish patients. These data indicate large regional differences in disease perception of MG, which is important to consider in international studies.