Adult Myasthenia Gravis Patients Research Articles

Long-Term Healthcare Resource Utilization and Costs among Patients with Myasthenia Gravis: A Swedish Nationwide Population-Based Study

Introduction: Healthcare costs and societal impact of myasthenia gravis (MG), a potentially life-threatening rare, chronic neuromuscular disease, are sparsely studied. We assessed healthcare resource utilization (HCRU) and associated costs among patients with newly diagnosed (ND) and preexisting (PE) MG in Sweden. Methods: This observational, retrospective cohort study used data from four linkable Swedish nationwide population-based registries. Adult MG patients receiving pharmacological treatment for MG and having ≥24-month follow-up during the period January 1, 2010, to December 31, 2017, were included. Results: A total of 1,275 patients were included in the analysis, of which 554 patients were categorized into the ND MG group and 721 into the PE MG group. Mean (±SD) age was 61.3 (±17.4) years, and 52.3% were female. In the first year post-diagnosis, ND patients had significantly higher utilization of acetylcholinesterase inhibitors (96.0% vs. 83.9%), corticosteroids (59.6% vs. 45.8%), thymectomy (12.1% vs. 0.7%), and plasma exchange (3.8% vs. 0.6%); had higher all-cause (70.9% vs. 35.8%) and MG-related (62.5% vs. 18.4%) hospitalization rates with 11 more hospitalization days (all p < 0.01) and an increased risk of hospitalization (odds ratio [95% CI] = 4.4 [3.43, 5.64]) than PE MG. In year 1 post-diagnosis, ND MG patients incurred EUR 7,302 (p < 0.01) higher total all-cause costs than PE MG, of which 84% were estimated to be MG-related and the majority (86%) were related to inpatient care. These results remained significant also after controlling for baseline demographics and comorbidities (p < 0.01). In year 2 post-diagnosis, the all-cause medical costs decreased by ∼55% for ND MG from year 1 and were comparable with PE MG. Conclusion: In this population-based study, MG patients required significantly more healthcare resources in year 1 post-diagnosis than PE MG primarily due to more pharmacological treatments, thymectomies, and associated hospitalizations. These findings highlight the need to better understand potential factors including disease characteristics associated with increased health resource use and costs and need for more efficacious treatments early in the disease course.

Social support and medication adherence among adult myasthenia gravis patients in China: the mediating role of mental health and self-efficacy

BackgroundMyasthenia gravis (MG), a rare chronic neuromuscular disorder, is characterized by progressive physical decline and requires long-term pharmacological treatment. Due to the decline of physical and social abilities, MG patients are in great need of social support, including tangible and emotional support. This study aims to examine the association between social support and medication adherence and the possible mediating effects of mental health and self-efficacy among MG patients.MethodsA cross-sectional analysis of a nationwide MG registry was conducted on 865 patients under oral medication treatment in China between June and July 2022. Validated scales were used to measure the respondent’s mental distress (Four-item Patient Health Questionnaire), social support (Modified Medical Outcomes Study Social Support Scale), self-efficacy for medication use (Self-efficacy for Appropriate Medication Use Scale), and medication adherence (Morisky Medication Adherence Scale, MMAS).ResultsThe association between social support and medication adherence and possible mediating effects of mental distress and self-efficacy were tested by structural equation model, with significant demographic and disease-related factors adjusted. The respondents showed a very low level of medication adherence (71.2% poor adherence; 1.4% high adherence; mean MMAS = 4.65). The level of social support was positively associated with medication adherence, and such association was fully mediated by two indirect pathways: through self-efficacy (β = 0.07, proportion mediated = 63.8%); and through mental distress and then self-efficacy (β = 0.01, proportion mediated = 6.7%).ConclusionProvision of social support and interventions on mental health with emphasis on improving self-efficacy for medication use may effectively improve medication adherence among MG patients.

Rs1800629 polymorphism in TNF-alpha is associated with the susceptibility and initial short-term glucocorticoids efficacy in myasthenia gravis patients

Tumor necrosis factor-alpha (TNF-α) is a potent pro-inflammatory agent involved in various autoimmune and inflammatory diseases including myasthenia gravis (MG). In this study, we enrolled 409 adult MG patients and 487 healthy individuals to investigate the association between TNF-α polymorphism and MG. We found the rs1800629 A allele frequency was significantly higher in the MG group than in the control group. Subgroup analysis revealed that the A allele frequencies were significantly higher in the early-onset subgroup, non-thymoma subgroup, ocular-onset subgroup, and mild severity subgroup than in the control group. To minimize the interactions between clinical features, we used a comprehensive classification and found that the rs1800629 A allele frequency was significantly higher in the non-thymoma AChR-Ab negative subgroup than in the control group. In the analysis of initial short-term glucocorticoids (GC) efficacy in the treatment-naive patients, the rs1800629 A allele frequency was significantly higher in the unresponsive subgroup than in the responsive group and the control group. Logistic regression demonstrated the rs1800629 genotypes in the dominant model and disease duration prior to GC treatment independently contributed to initial short-term GC efficacy. In conclusion, our study revealed that in Chinese adult MG patients, rs1800629 polymorphism in TNF-α was associated with the susceptibility of MG and might indicate the initial short-term GC efficacy.

Development and Assessment of an Artificial Intelligence-Based Tool for Ptosis Measurement in Adult Myasthenia Gravis Patients Using Selfie Video Clips Recorded on Smartphones

Introduction: Myasthenia gravis (MG) is a rare autoimmune disease characterized by muscle weakness and fatigue. Ptosis (eyelid drooping) occurs due to fatigue of the muscles for eyelid elevation and is one symptom widely used by patients and healthcare providers to track progression of the disease. Margin reflex distance 1 (MRD1) is an accepted clinical measure of ptosis and is typically assessed using a hand-held ruler. In this work, we develop an AI model that enables automated measurement of MRD1 in self-recorded video clips collected using patient smartphones. Methods: A 3-month prospective observational study collected a dataset of video clips from patients with MG. Study participants were asked to perform an eyelid fatigability exercise to elicit ptosis while filming “selfie” videos on their smartphones. These images were collected in nonclinical settings, with no in-person training. The dataset was annotated by non-clinicians for (1) eye landmarks to establish ground truth MRD1 and (2) the quality of the video frames. The ground truth MRD1 (in millimeters, mm) was calculated from eye landmark annotations in the video frames using a standard conversion factor, the horizontal visible iris diameter of the human eye. To develop the model, we trained a neural network for eye landmark detection consisting of a ResNet50 backbone plus two dense layers of 78 dimensions on publicly available datasets. Only the ResNet50 backbone was used, discarding the last two layers. The embeddings from the ResNet50 were used as features for a support vector regressor (SVR) using a linear kernel, for regression to MRD1, in mm. The SVR was trained on data collected remotely from MG patients in the prospective study, split into training and development folds. The model’s performance for MRD1 estimation was evaluated on a separate test fold from the study dataset. Results: On the full test fold (N = 664 images), the correlation between the ground truth and predicted MRD1 values was strong (r = 0.732). The mean absolute error was 0.822 mm; the mean of differences was −0.256 mm; and 95% limits of agreement (LOA) were −0.214–1.768 mm. Model performance showed no improvement when test data were gated to exclude “poor” quality images. Conclusions: On data generated under highly challenging real-world conditions from a variety of different smartphone devices, the model predicts MRD1 with a strong correlation (r = 0.732) between ground truth and predicted MRD1.

Attitudes and Beliefs Toward Thymectomy in the Myasthenia Gravis Patient Registry.

To evaluate patient attitudes and beliefs toward thymectomy for myasthenia gravis (MG). The Myasthenia Gravis Foundation of America administered a questionnaire to the MG Patient Registry, an ongoing longitudinal survey of adult MG patients. Questions assessed reasons for or against thymectomy and how hypothetical scenarios would have affected their decision. Of 621 respondents, 190 (31%) reported a history of thymectomy. Of those who underwent thymectomy for nonthymomatous MG, 97 (51.6%) ranked symptom improvement as most important and 100 (53.2%) ranked reducing medication as least important. Among 431 nonthymectomy patients, the most frequent reason for not undergoing thymectomy was that their doctor did not discuss it (152 of 431 = 35.2%) and 235 (56.8%) said that they would have considered it more strongly if their doctor spent more time discussing it. Thymectomies are motivated more by symptoms than by medication, and a lack of neurologist discussion is the most common barrier to thymectomy.

Effect of Light-Intensity Cycle Ergometer Aerobic Exercise on 2-Min Walking Test Distance and Maximum Oxygen Uptake in Myasthenia Gravis Patients: A Randomized Controlled Trial

Introduction: Fatigue and impaired functional capacity are more likely to be observed with myasthenia gravis (MG). MG prevalence in the Indonesian population is still limited. MG can benefit from participating in aerobic exercise without causing a decline in function, but relatively few exercise training studies have been conducted in this group of patients. This study analyzed how light-intensity cycle ergometer aerobic exercise influences functional and aerobic capacity in MG. Methods: An 8-week randomized controlled trial using a light-intensity cycle ergometer for aerobic exercise three times a week was carried out on adult patients with MG Foundation of America Class I-IIa, and adult patients. Eighteen MG patients were randomly assigned to the intervention or control group (standard exercise training). Two-min walking tests (2MWTs) distance and maximum oxygen uptake (VO2Max) were measured before and after the 8-week intervention. VO2Max was calculated from the 2MWT formula. A t-test was used to compare 2MWT distance and VO2Max within and between groups with a significance level of P &lt; 0.05. Results: Light intensity cycle ergometer aerobic exercise significantly improved the functional and aerobic capacity in the intervention group at 8 weeks (2MWT distance P = 0.001 and VO2Max P = 0.001) but not in the control group (P = 0.523 and P = 0.575, respectively). Substantial changes were also found between groups in both 2MWT distances (P = 0.002; effect size = 1.75) and VO2Max (P = 0.001; effect size = 1.81) pre- and post-test. Conclusion: Eight weeks of light-intensity cycle ergometer aerobic exercise improves the functional and aerobic capacity of adult MG patients.

Clinical characteristics and outcome predictors of a Chinese childhood-onset myasthenia gravis cohort.

Myasthenia gravis is an organ-specific autoimmune disease. Currently there is no universal guidelines for childhood-onset myasthenia gravis, therefore, treatment strategies are usually based on the guidelines from adult myasthenia gravis patients. In order to contribute in the process of the development of the universal childhood-onset myasthenia gravis guideline, we have summarized the clinical characteristics, treatment strategies, outcome and the related predictors of childhood-onset myasthenia gravis. We recruited 343 childhood-onset myasthenia gravis cases who were followed up at the Department of Pediatrics, Xiangya Hospital from June, 2010 to December, 2019. The data about clinical characteristics, treatments and outcome were collected and analyzed. Among of the 343 cases, 164 cases were followed up for longer than 2 years, of whom 142 still remained with ocular myasthenia gravis at the endpoint. About the treatments, 27 cases (27/164) accepted pyridostigmine only while the rest accepted glucocorticoid and/or other immunosuppressants. At the endpoint, the proportion of optimal outcome was 66.2% in the group remaining with ocular myasthenia gravis and 31.8% in the generalized myasthenia gravis group. Multivariate logistic regression analysis revealed that generalized myasthenia gravis type and positive status of antibodies against acetylcholine receptors were the independent risk factors for poor outcome. In conclusion, our childhood-onset myasthenia gravis patients present mainly as ocular myasthenia gravis, adequate immunotherapy improve the long-term outcome, and generalized myasthenia gravis phenotype as well as positive status of antibodies against acetylcholine receptors relate to poor outcome.

Pharmacosafety of fluoroquinolone and macrolide antibiotics in the clinical care of patients with myasthenia gravis.

Anecdotal case reports have suggested a potential association of fluoroquinolones and macrolides with myasthenia gravis (MG) exacerbation, prompting warnings against the use of these drugs in this population. However, large-scale and reliable population-based data that demonstrate this association are lacking. This study aims to examine the association between outpatient treatment with fluoroquinolones or macrolides and MG-related hospitalization. A retrospective cohort study consisting of adult MG patients was conducted using a large de-identified healthcare claims database. Antibiotic prescription claims were identified, and MG-related hospitalizations were assessed at 15, 30, and 90 days after the date of prescription. We used mixed effects survival regression with log-logistic distribution and independent covariance matrix to estimate odds ratios (ORs) of hospitalization for each potentially exacerbating antibiotic using beta-lactam as the reference and adjusting for covariates. Among 1556 MG patients receiving 894 fluoroquinolone prescriptions, 729 macrolide prescriptions, and 1608 beta-lactam prescriptions during the study period, there was no difference in 15, 30, or 90-day odds of MG-related hospitalization between fluoroquinolone or macrolide users compared to prescribed beta-lactams. However, estimates were higher for fluoroquinolones than macrolides, even after covariate adjustment (adjusted OR [aOR] 4.60, 95% confidence interval [CI] 0.55-38.57 for fluoroquinolones and OR 0.56, 95% CI 0.32-0.97 for macrolides, respectively, at 15 days). Fluoroquinolone and macrolide antibiotics are prescribed frequently to patients with MG. While statistical imprecision precludes a definitive conclusion, elevated ORs for fluoroquinolones raise the possibility of an underpowered association that merits further investigation.

Complement C3 polymorphism is associated with the susceptibility of myasthenia gravis in Chinese adult patients

Complement component 3 (C3) had been proved to be involved in the pathogenesis and exacerbation of both myasthenia gravis (MG) patients and experimental autoimmune myasthenia gravis (EAMG) models. We evaluated the underlying association between five SNPs (rs344555, rs7951, rs3745568, rs366510 and rs163913) in C3 gene and Chinese adult MG patients. Our study consisted of 409 adult MG patients and 487 healthy controls. Subgroups were classified by gender, onset age, thymoma, anti-AChR antibody, onset muscle involvement (ocular/generalized) and severity (Oosterhuis score at the maximal severity during the initial two years after the onset of MG). We found significant differences in allele frequencies between MG and the control group, between various MG subgroups and the control group in rs344555 and rs3745568. There were significant differences in genotype frequencies between MG group and the control group, between MG subgroups and the control group under the codominant and additive inheritance models in rs344555 and rs3745568. No association was found between the frequencies of these SNPs and the severity of MG. We also used a comprehensive classification which was close to the clinical scenario to minimize the interaction among clinical features. In rs344555, the T allele frequency in thymoma (−) AChR-Ab (+) subgroup was significantly higher than that in the control group. Our results indicated that rs344555 was associated with the susceptibility of Chinese adult MG patients; rs3745568 was probably associated with the susceptibility of Chinese adult MG patients. No association was found between the frequencies of these SNPs and the severity of MG.

Myasthenia Gravis and COVID-19: Clinical Characteristics and Outcomes.

Myasthenia gravis (MG), an autoimmune neuromuscular disorder, may be a risk factor for severe COVID-19. We conducted an observational retrospective study with 15 consecutive adult MG patients admitted with COVID-19 at four hospitals in São Paulo, Brazil. Most patients with MG hospitalized for COVID-19 had severe courses of the disease: 87% were admitted in the intensive care unit, 73% needed mechanical ventilation, and 30% died. Immunoglobulin use and the plasma exchange procedure were safe. Immunosuppressive therapy seems to be associated with better outcomes, as it might play a protective role.

Efficacy and tolerability of subcutaneously administered immunoglobulin in myasthenia gravis: A systematic review

Subcutaneous immunoglobulin (SCIg) is an emerging therapeutic alternative in the management of myasthenia gravis (MG) due to its potential efficacy, safety, cost effectiveness and ease of administration. At present, there are no systematic reviews that summarized the effects of SCIg in patients with MG. The objective of this study is to determine the efficacy and safety of SCIg in the treatment of adult patients with myasthenia gravis. Relevant records were identified from August 2018 to January 2019 systematic search. Five relevant articles with a total of 34 patients with MG were included in this review. Data on functional disability score and adverse events were obtained. Based on the included uncontrolled studies, the functional disability scores of adult MG patients after SCIg administration showed consistent improvement. Headache and local site injection reactions were the most common adverse events reported. The evidence from limited uncontrolled studies gathered in this review showed that SCIg may improve functional disability in patients with MG. Local and mild adverse events were reported with its administration, but no systemic and serious adverse events were noted.

High efficacy of rituximab for myasthenia gravis: a comprehensive nationwide study in Austria.

Most patients with myasthenia gravis (MG) need long-term immunosuppressive therapy. However, conventional agents may have intolerable side effects, take too long or fail to achieve disease control. Rituximab (RTX) has emerged as an off-label treatment for refractory MG, but data on its use are still sparse. We conducted a retrospective nationwide study contacting all Austrian neurologists to provide anonymized data of all adult MG patients treated with RTX and minimum follow-up of 3months. The Myasthenia Gravis Foundation of America Postintervention Status scale was used to assess outcomes. 34 (60.7%) of a total of 56 patients were women. Median (IQR) age at diagnosis of MG and start of RTX were 41.5 (24.3; 65.8) and 47.5(33; 71)years, respectively. Antibodies (ab) against acetylcholine receptor (AchR) and muscle-specific tyrosine kinase (MuSK) were present in 69.6% and 25% of patients, respectively (seronegative: 5.4%). Before RTX, 47 (83.9%) patients had had plasma exchange, immune adsorption or immunoglobulins. Three months after RTX, 14 of 53 (26.4%) patients were in remission. At last follow-up after a median of 20(10; 53)months, remission was present in 42.9% of patients and another 25% had minimal manifestations. Remission was more frequent in patients with MuSK ab vs. those with AchR ab (71.4% vs. 35.9%, p = 0.022). RTX was safe. The presence of MuSK ab independently predicted remission after RTX. In this retrospective study on RTX for MG, the largest to date, RTX appeared safe, efficacious and fast acting. Benefit from RTX was greatest in MuSK ab + MG.

TNFAIP3 gene rs7749323 polymorphism is associated with late onset myasthenia gravis.

In this study, we intended to genotype 2 single nucleotide polymorphisms (SNPs) of tumor necrosis factor α-induced protein 3 (TNFAIP3) genes and explore an association of TNFAIP3 genetic polymorphism with the patients of myasthenia gravis (MG) at clinical level. In brief, 215 of adult MG patients were divided into subgroups according to their clinical features, age of onset, thymic pathology, and autoantibodies. Two hundred thirty-five of healthy controls were also divided into subgroups with gender- and age-matched. The allele and genotype frequencies of subgrouped patients were found to be higher than those of healthy controls. The distribution of TNFAIP3 gene rs7749323∗A allele of late onset MG (LOMG, with positive acetylcholine receptor antibody and without thymoma) subgrouped patients was also significantly higher than that of gender- and age-matched healthy controls (7.4% vs 2.4%, odds ratio [OR] = 3.27, 95% confidence interval [CI] 1.01–10.6, P = .04). Furthermore, analysis to the genotype frequencies indicates that the carriers of rs7749323∗A allele of LOMG group became more frequent than that of age-matched healthy controls (14.9% vs 4.8%, OR = 3.47, 95% CI 1.04–11.6, dominant model: P = .03). It is interesting to notice that there is no significant association between the rs7749323 and susceptibility of other MG subgroups. Therefore, it is suggested that the SNPs in the 3′ flanking region (rs7749323) of TNFAIP3 gene and the genetic variations of TNFAIP3 gene may take an important role in the susceptibility of LOMG.

Juvenile-onset myasthenia gravis: autoantibody status, clinical characteristics and genetic polymorphisms.

Myasthenia gravis (MG) is an autoimmune disorder mediated by antibodies against proteins at the neuromuscular junction. Juvenile-onset MG (JMG) has been reported to have special characteristics. It is still unclear whether there are any pathogenic and genetic differences between juvenile and adult MG. In this study, we evaluated the clinical characteristics, autoantibody status (antibodies against AChR, MuSK, LRP4, titin and RyR) and genetic susceptibility (CHRNA1, CTLA4 and AIRE) in 114 Chinese JMG patients, and compared with 207 young adult MG patients (onset age 18-40years). JMG patients were classified into two subgroups: the very early onset group (<8years) and puberty onset group (8-18years). The very early onset MG patients had a higher proportion of ocular MG and thymus hyperplasia, compared with puberty onset MG and young adult MG (P<0.05). AChR antibodies were found in majority of JMG patients and were associated with more severe disease (P<0.05), while other antibodies were rare in JMG. Moreover, the very early onset MG had a more prominent genetic predisposition than puberty and adult MG, affecting the susceptible genes CHRNA1 and CTLA4. JMG has the same pathogenic background as adult MG, but has typical clinical features and a prominent genetic predisposition in very early onset patients (<8years). Specific therapeutic considerations are needed.

Gene Polymorphisms for Both Auto-antigen and Immune-Modulating Proteins Are Associated with the Susceptibility of Autoimmune Myasthenia Gravis.

Myasthenia gravis (MG) is an antibody-mediated autoimmune disease against antigens at the neuromuscular junction. Both genetic and environmental factors contribute to the susceptibility of MG. We undertook a case-control study to explore the contribution of genes of the auto-antigen and immune-modulating proteins in the pathogenesis of MG. We enrolled 389 adult MG patients and 487 healthy controls. Eighteen SNPs were selected from genes of cholinergic receptor nicotinic alpha 1 (CHRNA1), autoimmune regulator (AIRE), cytotoxic T lymphocyte-associated protein 4 (CTLA-4), protein tyrosine phosphatase nonreceptor type 22 (PTPN22), and interleukin-10 (IL-10). Rs16862847 and rs2229957 in CHRNA1, rs3761389 in AIRE, and rs733618 in CTLA-4 were significantly associated with MG, with the highest association in SNPs of CHRNA1. Carrier of rs16862847 G allele was found to be an independent risk factor in predicting high-level acetylcholine receptor (AChR) antibodies (P = 0.003, OR = 10.296). Genetic interaction analysis revealed a synergistic effect of CHRNA1 (rs16862847), AIRE (rs3761389), and CTLA-4 (rs733618) in the susceptibility of MG (P < 0.0001, OR = 1.95). These findings highlight the role of auto-antigen gene (CHRNA1) in the autoimmune reactions against AChR and reveal synergistic contribution of genes of both auto-antigen and immune-regulating proteins (AIRE and CTLA-4) in the pathogenesis of MG.

Heterogeneous immunogenetic background in Japanese adults with myasthenia gravis

The aim of this study was to elucidate the roles of human leukocyte antigen (HLA) class II genes in disease susceptibility in Japanese adult patients with myasthenia gravis (MG). A number of studies have shown that MG is correlated with DR3 in Caucasians. In Japanese, infantile MG is associated with DR9, but the HLA class II alleles associated with adult MG remains unclear. HLA-DRB1 and DQB1 alleles were determined by genotyping in 75 Japanese adult patients with MG and in 115 race-matched healthy adults. No statistically significant difference was observed in the overall prevalences of DRB1 and DQB1 alleles between MG patients and healthy controls, even when the patients and controls were stratified on the basis of their gender. MG patients with DQB1*0604 were younger and those with DQB1*0402 were older at disease onset than those without ( P=0.03 and 0.008, respectively). Concomitant autoimmune thyroid disease was associated with DRB1*0803 ( P=0.0009, corrected P=0.04). In addition, anti-acetylcholine receptor antibody levels were significantly higher in patients with DQB1*0604 than in those without ( P=0.045). These findings indicate that immunogenetic backgrounds in Japanese adult MG patients are heterogeneous and are apparently different from those in Caucasian patients.