Analysis of an adult Duchenne muscular dystrophy population

Use of a dynamic arm support to drive a power wheelchair: a case report

PURPOSE

Dynamic arm supports (DAS) can assist individuals with severe upper limb disabilities who use a wheelchair to accomplish their daily activities. The objective of this case series was to assess the potential of a DAS to improve power wheelchair (PWC) control in real-life contexts and to describe the integration process. A secondary objective was to explore factors that may influence the DAS integration process.

METHODS

This case series includes four participants fitted with the Kinova DAS O110. A one-year follow-up was planned for each participant with qualitative and quantitative data collection to assess DAS outcomes. Assessment methods were selected to cover the three vantages of assistive technology outcomes assessment: effectiveness, subjective well-being, and social significance.

RESULTS

Among the four participants, one used the DAS to help with his wheelchair control for at least 12 months (successful integration). For him, the DAS led to significantly improved wheelchair skills and an important positive psychosocial impact. He was, however, only able to use the DAS for PWC control (no effects on other daily activities), and could not use it in some contexts because the device increased his PWC width. As for the other participants, they stopped using the DAS for different reasons, including a DAS-related adverse event.

CONCLUSION

This study demonstrated that a wheelchair-bound DAS has the potential to improve PWC use, but successful integration requires specific factors. The service delivery process and the environmental accessibility are crucial for the successful integration of such a device and to avoid safety issues.IMPLICATIONS FOR REHABILITATIONNo study deeply assessed the impacts of dynamic arm support on power wheelchair control, and the associated facilitators and obstacles.A wheelchair-bound dynamic arm support has the potential to improve power wheelchair control for individuals with upper limb disabilities and to lead to positive psychosocial impacts if some conditions conductive to successful integration are met.The service delivery process and the environmental accessibility appear as crucial aspects for the successful integration of a new device, such as dynamic arm support and avoiding safety issues.

Comorbidities and medical complexities of mobility device users: a retrospective study

OBJECTIVE

To determine the medical complexities and comorbidities of individuals who utilise wheeled mobility devices. As well as, to examine costly events including the number of urinary tract infections (UTIs), hospitalizations, urgent care(UC)/emergency department (ED) visits that are commonly seen in this population over a period of time one year prior to and one year post receiving their wheeled mobility equipment.

DESIGN/SETTING

A retrospective data review of 857 individual medical charts at a Level 1 Trauma Hospital and Clinic System.

PARTICIPANTS

330 male and female (24-92 years old) mobility device users with a wide range of diagnoses, of which: 56 used manual wheelchairs (MWC),138 scooters (POV), 123 power wheelchairs without integrated standing (PWC), and 13 power wheelchairs with integrated standing (iS-PWC).

RESULTS

Overall, 92% (n = 304) had at least three medical comorbidities and medical complexities. The most common comorbidity was pain (91%). A change was noted in a lower incidence of UTIs in those using an iS-PWC, respectively 23% with at least 1 UTI in the year prior to and 8% in the year after the mobility device evaluation.

CONCLUSIONS

The large number of comorbidities and medical complexities amongst all mobility device users is concerning. The burden and the accompanying healthcare costs of this population is high. The potential that iS-PWC and other interventions could have on reducing these issues should be explored further.Implications of rehabilitationRegardless of a person's primary diagnosis or the wheeled mobility device they use, 100% have at least one and 92% have at least three comorbidities and medical complexities if they spend the majority of their day sittingThe high healthcare cost situations such as Emergency Department visits, Urgent Care visits, hospitalizations, and Urinary Tract Infections are present across those that use all mobility device types and the means to potentially reduce these incidences should be further exploredThe introduction of integrated standing within a power wheelchair, as a means to minimize the frequency of comorbidities and medical complications, should also be investigated further.

One in five patients with Duchenne muscular dystrophy dies from other causes than cardiac or respiratory failure

Duchenne muscular dystrophy (DMD) is a severe neuromuscular disorder with increasing life expectancy from late teens to over 30 years of age. The aim of this nationwide study was to explore the prevalence, life expectancy and leading causes of death in patients with DMD in Sweden. Patients with DMD were identified through the National Quality Registry for Neuromuscular Diseases in Sweden, the Swedish Registry of Respiratory Failure, pathology laboratories, neurology and respiratory clinics, and the national network for neuromuscular diseases. Age and cause of death were retrieved from the Cause of Death Registry and cross-checked with medical records. 373 DMD patients born 1970–2019 were identified, of whom 129 patients deceased during the study period. Point prevalence of adult patients with DMD on December 31st 2019 was 3.2 per 100,000 adult males. Birth prevalence was 19.2 per 100,000 male births. Median survival was 29.9 years, the leading cause of death being cardiopulmonary in 79.9% of patients. Non-cardiopulmonary causes of death (20.1% of patients) mainly pertained to injury-related pulmonary embolism (1.3 per 1000 person-years), gastrointestinal complications (1.0 per 1000 person-years), stroke (0.6 per 1000 person-years) and unnatural deaths (1.6 per 1000 person-years). Death from non-cardiopulmonary causes occurred at younger ages (mean 21.0 years, SD 8.2; p = 0.004). Age at loss of independent ambulation did not have significant impact on overall survival (p = 0.26). We found that non-cardiopulmonary causes contribute to higher mortality among younger patients with DMD. We present novel epidemiological data on the increasing population of adult patients with DMD.

The variability in neurological deficits in Duchenne muscular dystrophy patients may be explained by differences in dystrophin glycoprotein complexes in the brain and muscle

Duchenne muscular dystrophy (DMD) is an X-linked recessive genetic neuromuscular disorder. The variability in neurologic deficits in DMD patients may be explained by the fact that (1) dystrophin containing complexes in the brain are more stable than dystrophin containing complexes in the muscle (2) neurons are not affected by the same stresses as muscle and (3) neurons have a greater capacity to buffer increases in intracellular calcium levels. In the muscle, the loss of dystrophin and subsequent loss of dystrophin-associated proteins (DAPs) affects the stability of the dystrophin-glycoprotein complex and calcium ion channels. It causes the sarcolemma of the muscle to tear and calcium ion leak. The subsequent calcium influx leads to calcium dependant proteolysis. In the brain, the structure of the dystrophin-containing complexes is completely different from the muscle. There are several dystrophin isoforms that combine with a completely different set of proteins compared to the muscle to form several different dystrophin-containing complexes. In addition, the loss of dystrophin does not affect the expression of DAPs. The heterogeneity of dystrophin-containing complexes and the continued expression of DAPs will result in more stable dystrophin-containing complexes in the DMD brain. Muscles are under more stress than neurons as they undergo contractions. This combined with txhe fact that the neurons have a better ability to buffer increases in calcium would suggest that neurons are less likely to be damaged despite the loss of dystrophin.

Occurrence of symptoms in different stages of Duchenne muscular dystrophy and their impact on social participation

Introduction/Aims

As life expectancy improves for patients with Duchenne muscular dystrophy (DMD), new symptoms are likely to arise. This aims of this study are: (1) to explore the prevalence of a broad variety of symptoms in the various stages of DMD (with and without steroid use); (2) to explore the prevalence of common secondary diagnoses; and (3) to evaluate the social participation level of patients with DMD older than 16 y of age; and to explore correlations between social participation and symptoms.

Methods

A cross‐sectional self‐report questionnaire, including questions on functional level and health status, as well as a standardized participation scale was distributed among Dutch patients with DMD.

Results

Eighty‐four male patients with a mean age of 22.0 (SD = 10.0) y were enrolled. The most prevalent and limiting symptoms were difficulty coughing (58%), coldness of hands (57%), contractures (51%), stiffness (49%), fatigue (40%), myalgia (38%), and low speech volume (33%). Prevalent secondary diagnoses included cardiac disease (14%), neurobehavioral diagnosis (13%), low blood pressure (13%), and arthrosis (5%). Social participation correlated negatively with coldness of hands (r = − .29; P < .03), decreased intelligibility (r = − .40; P < .003), and chewing problems (r = − .33; P < .02).

Discussion

The prevalence of a broad spectrum of symptoms and secondary diagnoses is high in patients with DMD, and some of these symptoms are correlated with social participation. Growing awareness of new symptoms and secondary diagnoses among patients, caregivers, and professionals can enhance their recognition, possibly facilitating prevention and early treatment.

Duchenne muscular dystrophy: Genetic and clinical profile in the population of Rajasthan, India

Background:

Materials and Methods:

Results:

Conclusions:

Relationship between Eating and Digestive Symptoms and Respiratory Function in Advanced Duchenne Muscular Dystrophy Patients

Background:

Duchenne muscular dystrophy (DMD) patients can have various issues that affect their quality of life, including eating and digestive conditions.

Objective:

We sought to identify the relationship between respiratory function and various eating and digestion related symptoms in patients with advanced Duchenne muscular dystrophy (DMD).

Methods:

Eating and digestive symptoms, including loss of appetite, nausea, vomiting, diarrhea, constipation, swallowing difficulty, mastication difficulty, early satiety, and aspiration, were evaluated among patients with advanced DMD who were nonambulatory and required noninvasive mechanical ventilatory support. In addition, various respiratory function parameters were measured, including forced vital capacity (FVC), maximal insufflation capacity (MIC), peak cough flow (PCF), assisted PCF (APCF), maximal inspiratory pressure (MIP), and maximal expiratory pressure (MEP). We then analyzed the relationship between gastrointestinal symptoms and respiratory function parameters.

Results:

A total of 180 patients (age, 22.3±5.0 years) were included in the analysis. Loss of appetite and early satiety showed no correlation with any of the respiratory function parameters. Constipation was correlated with MEP; swallowing difficulty was correlated with MIC, APCF, MIP and MEP; and mastication difficulty was correlated with FVC, PCF, APCF, MIP, and MEP. Notably, age did not correlate with any gastrointestinal symptoms.

Conclusions:

Eating and digestive symptoms are more closely correlated with respiratory function than with age in patients with DMD. We think this correlation is mainly caused by the skeletal muscle strength, which is major determinant of both digestive and respiratory function.

Liberation and mortality outcomes in pediatric long-term ventilation: A qualitative systematic review

OBJECTIVE

To provide a systematic review of liberation from positive pressure ventilation and mortality of children with chronic respiratory failure who used long-term invasive and noninvasive ventilation (LTV).

METHODS

Papers published from 1980 to 2018 were identified using Pubmed MEDLINE, Ovid MEDLINE, Embase, and Cochrane databases. Search results were limited to English-language papers with (a) patients less than 22 years at initiation, (b) patients who used invasive ventilation (IV) via tracheostomy or noninvasive ventilation (NIV), and (c) data on mortality or liberation from LTV. Data were presented using descriptive statistics; changes in outcomes over time were explored using linear regression. Follow-up variability, cohort heterogeneity, and insufficient data precluded combining data to estimate incidences or rates.

RESULTS

One hundred and thirty papers with 12 704 patients were included. The median number of patients was 37 (interquartile range [IQR] 17-74, range 6-3802). Twenty-five percent of patients were initiated on IV; 75% on NIV. The maximum follow-up ranged from 0.5 to 31.8 years (median 8.8 years). The median proportion of patients liberated in these papers was 3% (IQR 0%-21%). The median proportion of mortality was 18% (IQR 8%-27%). Proportions of liberation and mortality did not significantly change over time. Progression of underlying disease (44%), respiratory illness (19%), and LTV accident (11%) were the most common causes of death.

CONCLUSIONS

These papers collectively show most patients survive for many years using LTV; in many subgroups, death is a more common outcome than liberation. However, the limitations of these papers preclude robust prognostication.

Multiple poloxamers increase plasma membrane repair capacity in muscle and nonmuscle cells

Various previous studies established that the amphiphilic tri-block copolymer known as poloxamer 188 (P188) or Pluronic-F68 can stabilize the plasma membrane following a variety of injuries to multiple mammalian cell types. This characteristic led to proposals for the use of P188 as a therapeutic treatment for various disease states, including muscular dystrophy. Previous studies suggest that P188 increases plasma membrane integrity by resealing plasma membrane disruptions through its affinity for the hydrophobic lipid chains on the lipid bilayer. P188 is one of a large family of copolymers that share the same basic tri-block structure consisting of a middle hydrophobic propylene oxide segment flanked by two hydrophilic ethylene oxide moieties [poly(ethylene oxide)80-poly(propylene oxide)27-poly(ethylene oxide)80]. Despite the similarities of P188 to the other poloxamers in this chemical family, there has been little investigation into the membrane-resealing properties of these other poloxamers. In this study we assessed the resealing properties of poloxamers P181, P124, P182, P234, P108, P407, and P338 on human embryonic kidney 293 (HEK293) cells and isolated muscle from the mdx mouse model of Duchenne muscular dystrophy. Cell membrane injuries from glass bead wounding and multiphoton laser injury show that the majority of poloxamers in our panel improved the plasma membrane resealing of both HEK293 cells and dystrophic muscle fibers. These findings indicate that many tri-block copolymers share characteristics that can increase plasma membrane resealing and that identification of these shared characteristics could help guide design of future therapeutic approaches.

Inhibition of the Activin Receptor Type-2B Pathway Restores Regenerative Capacity in Satellite Cell-Depleted Skeletal Muscle

Degenerative myopathies typically display a decline in satellite cells coupled with a replacement of muscle fibers by fat and fibrosis. During this pathological remodeling, satellite cells are present at lower numbers and do not display a proper regenerative function. Whether a decline in satellite cells directly contributes to disease progression or is a secondary result is unknown. In order to dissect these processes, we used a genetic model to reduce the satellite cell population by ~70–80% which leads to a nearly complete loss of regenerative potential. We observe that while no overt tissue damage is observed following satellite cell depletion, muscle fibers atrophy accompanied by changes in the stem cell niche cellular composition. Treatment of these mice with an Activin receptor type-2B (AcvR2B) pathway blocker reverses muscle fiber atrophy as expected, but also restores regenerative potential of the remaining satellite cells. These findings demonstrate that in addition to controlling fiber size, the AcvR2B pathway acts to regulate the muscle stem cell niche providing a more favorable environment for muscle regeneration.

Development of a New Self-Reporting Instrument Measuring Benefits and Side Effects of Corticosteroids in Duchenne Muscular Dystrophy: Report from a Pilot Study

BACKGROUND

There is no cure for Duchenne Muscular Dystrophy (DMD); treatment is symptomatic and corticosteroids slow the progression. Side effects of corticosteroids - especially the physical effects - have been described, however patients' and caregivers perception on chronic corticosteroid treatment and their side effects is less well known, in particular with regards to cognition, behaviour, and emotional functioning.

OBJECTIVE

The primary aim of this pilot study was to (i) construct a self-report questionnaire to assess the perceived benefits and side effects of corticosteroids for patients with DMD and their parents. Furthermore we aimed to (ii) investigate the psychometric qualities of this questionnaire, (iii) whether there was a difference between parents' and patient's perceptions, and finally (iv) to what extent reported side effects may alter over time.

METHODS

A 23-item questionnaire (SIDECORT: side effect of corticosteroids) was constructed to assess the perception of these benefits and side effects in a systematic manner.

RESULTS

In total, 86 patients (aged 5 - 28 years) and 125 of their parents completed the questionnaire. Internal consistency was good. Using factor analyses on the side effect items as reported by parents, two underlying factors were found, with the first factor describing cognitive, behavioural and emotional functioning, and the second factor describing physical functioning. The potential benefits of corticosteroids were highly rated among both parents and patients, although parents rated the importance of the benefits higher than their sons (p = 0.002). Similarly, parents rated the severity of the side effects generally higher than their sons (p = 0.011), especially with regards to the physical side effects (p = 0.014). Based on the parent's perception, the neurodevelopmental side effects generally appeared to decline the longer corticosteroids were used.

CONCLUSIONS

To our knowledge, this is the first explicit study on perceived cognitive-, behavioural-, and emotional side effects and the allocation of benefits to corticosteroids in DMD. On the basis of our research we suggest a short form questionnaire, which proves to be reliable and valid for research- and clinical practice. This questionnaire could provide useful insights for the care of boys and men with DMD.

Antisense oligonucleotides: the next frontier for treatment of neurological disorders

Antisense oligonucleotides (ASOs) were first discovered to influence RNA processing and modulate protein expression over two decades ago; however, progress translating these agents into the clinic has been hampered by inadequate target engagement, insufficient biological activity, and off-target toxic effects. Over the years, novel chemical modifications of ASOs have been employed to address these issues. These modifications, in combination with elucidation of the mechanism of action of ASOs and improved clinical trial design, have provided momentum for the translation of ASO-based strategies into therapies. Many neurological conditions lack an effective treatment; however, as research progressively disentangles the pathogenic mechanisms of these diseases, they provide an ideal platform to test ASO-based strategies. This steady progress reached a pinnacle in the past few years with approvals of ASOs for the treatment of spinal muscular atrophy and Duchenne muscular dystrophy, which represent landmarks in a field in which disease-modifying therapies were virtually non-existent. With the rapid development of improved next-generation ASOs toward clinical application, this technology now holds the potential to have a dramatic effect on the treatment of many neurological conditions in the near future.

Clinical features of children and adults with a muscular dystrophy using powered indoor/outdoor wheelchairs: disease features, comorbidities and complications of disability. Disabil Rehabil 2017;40:1007-1013. [PMID: 28338349 DOI: 10.1080/09638288.2017.1292322]

PURPOSE

To describe the clinical features of electric powered indoor/outdoor wheelchair users with a muscular dystrophy, likely to influence optimal prescription; reflecting features of muscular dystrophies, conditions secondary to disability, and comorbidities impacting on equipment provision.

METHODS

Cross-sectional retrospective case note review of recipients of electric powered indoor/outdoor wheelchairs provided by a specialist regional wheelchair service. Data on demography, diagnostic/clinical, and wheelchair prescription were systematically extracted.

RESULTS

Fifty-one men and 14 women, mean age 23.7 (range 10-67, s.d. 12.95) years, were studied. Forty had Duchenne muscular dystrophy, 22 had other forms of muscular dystrophy, and three were unclassified. Twenty-seven were aged under 19. Notable clinical features included problematic pain (10), cardiomyopathy (5), and ventilatory failure (4). Features related to disability were (kypho)scoliosis (20) and edema/cellulitis (3) whilst comorbidities included back pain (5). Comparison of younger with older users revealed younger users had more features of muscular dystrophy affecting electric powered chair provision (56%) whilst older users had more comorbidity (37%). Tilt-in-space was prescribed for 81% of users, specialized seating for 55% and complex controls for 16%.

CONCLUSIONS

Muscular dystrophy users were prescribed electric powered indoor/outdoor chairs with many additional features reflecting the consequences of profound muscle weakness. In addition to facilitating independence and participation, electric powered indoor/outdoor chairs have major therapeutic benefits. Implications for rehabilitation Powered wheelchairs have therapeutic benefits in managing muscular dystrophy pain and weakness. The use of specialized seating needs careful consideration in supporting progressive muscle weakness and the management of scoliosis. Pain, discomfort, pressure risk, and muscle fatigue may be reduced by use of tilt-in-space.

Men with Duchenne muscular dystrophy and end of life planning

There is very limited evidence about the views of men with Duchenne muscular dystrophy (DMD) and end of life issues including death and dying. Studies have shown the physiological and psychological benefits of talking about and planning for end of life. Despite policy documents and guidance in the UK about end of life planning, there is consensus on the need for improvement. The study reported here is a qualitative one with 15 men with DMD (aged 20-45 years). Participants could not recall any significant conversations with clinicians about end of life and assumed that clinicians were reluctant to discuss the issue. The men in the study wanted to be given proactive cues that they could bring up topics such as death and dying and wanted to have these conversations with clinicians who combined expert knowledge about the condition as well as good listening skills. Topics of interest to participants included likely nature and place of death; practical planning for funerals and wills; and sources of information and support. Emotional or psychological support to think about end of life was not routinely offered and participants found it very difficult to discuss these issues with family members. The study suggests that more could be done to encourage clinicians, men with Duchenne, family members and the wider NMD community to pay attention to end of life planning issues and the associated need for emotional support and high quality interactions between patients and clinicians.

Gene therapies that restore dystrophin expression for the treatment of Duchenne muscular dystrophy

Duchenne muscular dystrophy is one of the most common inherited genetic diseases and is caused by mutations to the DMD gene that encodes the dystrophin protein. Recent advances in genome editing and gene therapy offer hope for the development of potential therapeutics. Truncated versions of the DMD gene can be delivered to the affected tissues with viral vectors and show promising results in a variety of animal models. Genome editing with the CRISPR/Cas9 system has recently been used to restore dystrophin expression by deleting one or more exons of the DMD gene in patient cells and in a mouse model that led to functional improvement of muscle strength. Exon skipping with oligonucleotides has been successful in several animal models and evaluated in multiple clinical trials. Next-generation oligonucleotide formulations offer significant promise to build on these results. All these approaches to restoring dystrophin expression are encouraging, but many hurdles remain. This review summarizes the current state of these technologies and summarizes considerations for their future development.

Prospective observational cohort study of patients with weaning failure admitted to a specialist weaning, rehabilitation and home mechanical ventilation centre

OBJECTIVES

According to National Health Service England (NHSE) specialist respiratory commissioning specification for complex home ventilation, patients with weaning failure should be referred to a specialist centre. However, there are limited data reporting the clinical outcomes from such centres.

SETTING

Prospective observational cohort study of patients admitted to a UK specialist weaning, rehabilitation and home mechanical ventilation centre between February 2005 and July 2013.

PARTICIPANTS

262 patients admitted with a median age of 64.2 years (IQR 52.6-73.2 years). 59.9% were male.

RESULTS

39.7% of patients had neuromuscular and/or chest wall disease, 21% were postsurgical, 19.5% had chronic obstructive pulmonary disease (COPD), 5.3% had obesity-related respiratory failure and 14.5% had other diagnoses. 64.1% of patients were successfully weaned, with 38.2% weaned fully from ventilation, 24% weaned to nocturnal non-invasive ventilation (NIV), 1.9% weaned to nocturnal NIV with intermittent NIV during the daytime. 21.4% of patients were discharged on long-term tracheostomy ventilation. The obesity-related respiratory failure group were most likely to wean (relative risk (RR) for weaning success=1.48, 95% CI 1.35 to 1.77; p<0.001), but otherwise weaning success rates did not significantly vary by diagnostic group. The median time-to-wean was 19 days (IQR 9-33) and the median duration of stay was 31 days (IQR 16-50), with no difference observed between the groups. Weaning centre mortality was 14.5%, highest in the COPD group (RR=2.15, 95% CI 1.19 to 3.91, p=0.012) and lowest in the neuromuscular and/or chest wall disease group (RR=0.34, 95% CI 0.16 to 0.75, p=0.007). Of all patients discharged alive, survival was 71.7% at 6 months and 61.8% at 12 months postdischarge.

CONCLUSIONS

Following NHSE guidance, patients with weaning delay and failure should be considered for transfer to a specialist centre where available, which can demonstrate favourable short-term and long-term clinical outcomes.

Impact of three genetic musculoskeletal diseases: a comparative synthesis of achondroplasia, Duchenne muscular dystrophy and osteogenesis imperfecta

Achondroplasia, Duchenne muscular dystrophy, and osteogenesis imperfecta are among the most frequent rare genetic disorders affecting the musculoskeletal system in children. Rare genetic disorders are severely disabling and can have substantial impacts on families, children, and on healthcare systems. This literature review aims to classify, summarize and compare these non-medical impacts of achondroplasia, Duchenne muscular dystrophy and osteogenesis imperfecta.

Investigation of Deaths of Chronically Disabled Persons and Institutionalized Persons

The investigation of deaths involving chronically disabled and/or institutionalized persons represents an important challenge to the medicolegal death investigation community. For the purposes of this review, the chronically disabled and/or institutionalized are considered to include three non-mutually exclusive subcategories: the disabled elderly, the severely disabled, and psychiatric patients. Because deaths within certain of these populations tend to be common and expected, a very important goal when such deaths occur is the appropriate referral of cases to the medical examiner/coroner. Although each subcategory has distinct issues of importance regarding death investigation, there is also a reasonable amount of overlap between the three groups. This review provides an overview of the three subcategories, the reasons such persons may be at risk for premature, unexpected, or unnatural death, the many important issues of concern when investigating deaths within these vulnerable populations, and important preventative strategies within each group.

Risk of fracture in patients with muscular dystrophies

The aim of the study was to determine fracture risk in incident muscular dystrophy (MD) patients. Patients with MD are at a 1.4-fold increased risk of fracture as compared with population-based control patients. Risk further increased among elderly and female patients and among patients exposed to oral glucocorticoids.

INTRODUCTION

Muscular dystrophies (MDs) are inherited diseases causing muscle weakness and thereby increase the risk of falling and detrimental effects on bone. Both are recognised risk factors for fracture. Therefore, the aim of this study was to determine the hazard ratio of fracture in patients with MD.

METHODS

We conducted a retrospective cohort study using the UK General Practice Research Database (1987-2012). Each patient with MD was matched by year of birth, sex and practice to up to six patients without a history of MD. Outcome measure was all fractures.

RESULTS

As compared with control patients, risk of any fracture was statistically significantly increased in MD patients (adjusted hazard ratio [AHR], 1.40; 95 % confidence interval [CI], 1.14-1.71). An increased risk of fracture was observed among MD patients with female gender (AHR, 1.78; 95 % CI, 1.33-2.40) and an increasing age as compared with control patients. Stratification to Duchenne MD showed no association with fracture, whereas risk of fracture was increased twofold among patients with myotonic dystrophy (AHR, 2.34; 95 % CI, 1.56-3.51). MD patients had an almost tripled risk of fracture when they used oral glucocorticoids in the previous 6 months as compared to non-users with MD.

CONCLUSION

Patients with MD are at a 1.4-fold increased risk of fracture as compared with population-based control patients. Especially in older age groups and female gender, the fracture risk of MD versus non-MD patients is increased, whereas exposure to glucocorticoids further increased fracture risk among MD patients.

Cardiomyopathy of Duchenne muscular dystrophy: pathogenesis and prospect of membrane sealants as a new therapeutic approach

Duchenne muscular dystrophy (DMD) is a devastating progressive disease of striated muscle deterioration. This fatal X-linked disorder results from the loss of the protein dystrophin, which in turn causes striated muscle membrane instability. Cardiac dysfunction is a growing problem in patients with DMD, but relatively little is known about the pathophysiology of the dystrophic heart. At present, there is no effective treatment for DMD and the current clinical approaches are primarily supportive in nature. This review will discuss the pathogenesis of DMD in the heart and discuss how these pathogenic processes have led to a new class of agents directed specifically at restoring membrane integrity to dystrophic myocardium. The tri-block poloxamers, specifically poloxamer 188 (P188), are able to stabilize the membranes of dystrophic myocardium in animal models and may offer a new therapeutic approach for cardiac disease in DMD.

Correlates of care for young men with Duchenne and Becker muscular dystrophy

INTRODUCTION

In progressive conditions, such as Duchenne and Becker muscular dystrophy (DBMD), the need for care may outpace care use. We examined correlates that contribute to utilization of needed care.

METHODS

Structured interviews were conducted on use of care among 34 young men with DBMD who were born before 1982.

RESULTS

Disease severity, per capita income, and presence of other relatives with DBMD predicted greater use of services. Race/ethnicity, acculturation, and level of caregiver education did not significantly predict service utilization.

CONCLUSIONS

We identified disparities in receipt of healthcare and related services in adult men with DBMD that can affect quality of life. Despite the high disease severity identified in this population, these men utilized only half of the services available to individuals with significant progressive conditions. Providers should be aware of low service utilization and focus on awareness and assistance to ensure access to available care.

Evolution of life expectancy of patients with Duchenne muscular dystrophy at AFM Yolaine de Kepper centre between 1981 and 2011

OBJECTIVES

Retrospective study over the last 30 years of life expectancy in patients suffering from Duchenne muscular dystrophy (DMD). Analysis of the role of ventilatory assistance and causes of death.

PATIENTS AND METHODS

One hundred and nineteen adult DMD patients were hosted during 1981 to 2011 at AFM Yolaine de Kepper centre, Saint-Georges-sur-Loire, France. Patients' life expectancy was calculated using Kaplan-Meier model.

RESULTS

Life expectancy without or with ventilatory assistance was 22.16 and 36.23 years, respectively. Similarly, life expectancy of patients born from 1970 (mostly with ventilatory assistance) was 40.95 years old from 1970 and 25.77 years old before 1970. Causes of death changed. Cardiac origins of death have increased from 8% to 44%.

CONCLUSION

Ventilator assistance, in this study mostly through tracheotomy prolongs by more than 15 years life expectancy of DMD patients. It allows conservation of a satisfactory quality of life, and should be systematically proposed to patients.

Dysphagia in Duchenne muscular dystrophy assessed by validated questionnaire

BACKGROUND

Duchenne muscular dystrophy (DMD) leads to progressive muscular weakness and death, most typically from respiratory complications. Dysphagia is common in DMD; however, the most appropriate swallowing assessments have not been universally agreed and the symptoms of dysphagia remain under-reported.

AIMS

To investigate symptoms of dysphagia in DMD and to determine the potential of the validated Sydney Swallow Questionnaire (SSQ) to diagnose dysphagia in this patient group.

METHODS & PROCEDURES

Three participant groups completed the SSQ and the results were compared: nine DMD participants with dysphagia, six DMD participants without dysphagia and 12 healthy controls.

OUTCOMES & RESULTS

The questionnaire scores for dysphagic DMD participants were significantly higher than for non-dysphagic DMD participants (p = 0.039) and for healthy controls (p ≤ 0.001). The diagnostic ability of the questionnaire was good for detecting dysphagia in participants with DMD (receiver operating characteristic (ROC) area under the curve = 0.89, p = 0.013), with a cut-off score of 224.5 (13.2%) giving a sensitivity of 0.78 and a specificity of 0.83 for determining dysphagia. Dysphagic participants rated time to eat a meal, swallowing hard food, swallowing thick liquids and needing to cough up or spit during meals with the highest severity of all questionnaire items. Results of the questionnaire by item are presented to inform the clinician of the symptoms of dysphagia in DMD.

CONCLUSIONS & IMPLICATIONS

DMD leads to pervasive symptoms of dysphagia. The simple SSQ is a clinically informative assessment tool for patients with DMD.

Barx2 is expressed in satellite cells and is required for normal muscle growth and regeneration

Muscle growth and regeneration are regulated through a series of spatiotemporally dependent signaling and transcriptional cascades. Although the transcriptional program controlling myogenesis has been extensively investigated, the full repertoire of transcriptional regulators involved in this process is far from defined. Various homeodomain transcription factors have been shown to play important roles in both muscle development and muscle satellite cell-dependent repair. Here, we show that the homeodomain factor Barx2 is a new marker for embryonic and adult myoblasts and is required for normal postnatal muscle growth and repair. Barx2 is coexpressed with Pax7, which is the canonical marker of satellite cells, and is upregulated in satellite cells after muscle injury. Mice lacking the Barx2 gene show reduced postnatal muscle growth, muscle atrophy, and defective muscle repair. Moreover, loss of Barx2 delays the expression of genes that control proliferation and differentiation in regenerating muscle. Consistent with the in vivo observations, satellite cell-derived myoblasts cultured from Barx2(-/-) mice show decreased proliferation and ability to differentiate relative to those from wild-type or Barx2(+/-) mice. Barx2(-/-) myoblasts show reduced expression of the differentiation-associated factor myogenin as well as cell adhesion and matrix molecules. Finally, we find that mice lacking both Barx2 and dystrophin gene expression have severe early onset myopathy. Together, these data indicate that Barx2 is an important regulator of muscle growth and repair that acts via the control of satellite cell proliferation and differentiation.

Barx homeobox family in muscle development and regeneration

Homeobox transcription factors are key intrinsic regulators of myogenesis. In studies spanning several years, we have characterized the homeobox factor Barx2 as a novel marker for muscle progenitor cells and an important regulator of muscle growth and repair. In this review, we place the expression and function of Barx2 and its paralogue Barx1 in context with other muscle-expressed homeobox factors in both embryonic and adult myogenesis. We also describe the structure and regulation of Barx genes and possible gene/disease associations. The functional domains of Barx proteins, their molecular interactions, and cellular functions are presented with particular emphasis on control of genes and processes involved in myogenic differentiation. Finally, we describe the patterns of Barx gene expression in vivo and the phenotypes of various Barx gene perturbation models including null mice. We focus on the Barx2 null mouse model, which has demonstrated the critical roles of Barx2 in postnatal myogenesis including muscle maintenance during aging, and regeneration of acute and chronic muscle injury.

Aging with muscular dystrophy: pathophysiology and clinical management

Major advances in the fields of medical science and physiology, molecular genetics, biomedical engineering, and computer science have provided individuals with muscular dystrophy (MD) with more functional equipment, allowing better strategies for improvement of quality of life. These advances have also allowed a significant number of these patients to live much longer. As progress continues to change management, it also changes patients' expectations. A comprehensive medical and rehabilitative approach to management of aging MD patients can often fulfill expectations and help them enjoy an enhanced quality of life.

Electric powered wheelchairs for those with muscular dystrophy: problems of posture, pain and deformity

PURPOSE

To identify areas of difficulty encountered by a regional wheelchair service in providing Electric Powered Indoor/outdoor wheelchairs (EPIOCs) to those with muscular dystrophy (MD) in the early years of their provision--particularly posture, pain and deformity.

METHOD

Wheelchair service records of all users between April 1997 and March 2000 were reviewed retrospectively and issues relating to weakness, pain/discomfort, deformities, other medical issues, weight change, function, posture and driving were documented on a purpose-designed proforma. Adjustments and modifications were documented over the 2-year period following chair delivery.

RESULTS

Of 325 EPIOC users on the departmental database, 29 had MD (15 Duchenne's), whose users charts were reviewed. Almost 80% of users needed clinical review within 2 years, mostly due to a scoliosis. Other problems were postural (66%), medical (48%), pain (31%), functional (24%) and weight change (14%). The commonest prescriptions were for specialised seating (24%), lateral supports, headrests and footrests (21% each).

CONCLUSIONS

The rate of disease progression was not planned for by the service. Most clients were seen in response to deterioration, rather than anticipating it. Planned reviews within 1 year appear essential for teenagers with MD with the dual issues of rapid maturation and progressive disease.

Mechanical ventilation in Duchenne patients with chronic respiratory insufficiency: clinical implications of 20 years published experience

Chronic respiratory insufficiency is inevitable in the course of disease progression in patients with Duchenne muscular dystrophy (DMD). Without mechanical ventilation (MV), morbidity and mortality are highly likely towards the end of the second decade of life. The present review reports evidence and clinical implications regarding DMD patients treated with MV. There is no doubt that nocturnal hypercapnia precedes daytime hypercapnia. Historical comparisons have provided evidence that non-invasive intermittent positive pressure ventilation (NIPPV) at night is effective and improves quality of life and survival by 5-10 years. By contrast, the optimal criteria and timing for initiation of NIPPV are inconsistent. A recent randomized study however demonstrated the benefits of commencing NIPPV as soon as nocturnal hypoventilation is detected (Ward S, et al., Randomised controlled trial of non-invasive ventilation (NIV) for nocturnal hypoventilation in neuromuscular and chest wall disease patients with daytime normocapnia. Thorax 2005; 60: 1019-24). The respective role of the three hypotheses of the indirect action of nocturnal NIPPV on daytime blood gases may be complimentary; the main improvement may be due to improved ventilatory response to CO2. The ultimate time to offer full time ventilation with the most advantageous interface is lacking in evidence. Full time NIV is possible with a combination of a nasal mask during the night and a mouthpiece during the day, however tracheostomy may be provided when mechanical techniques of cough-assistance are useless to treat chronic cough insufficiency.

Current treatment of adult Duchenne muscular dystrophy

Patients with Duchenne muscular dystrophy (DMD) are living longer into adulthood due to a variety of improvements in health care practices. This growing patient population presents new therapeutic challenges. In this article, we review the literature on current treatment of adult DMD as well as our own experience as a multidisciplinary team actively caring for 23 men ages 19-38 years of age. Approximately one quarter of our adult DMD patients have remained on moderate dose corticosteroids. Daily stretching exercises are recommended, particularly of the distal upper extremities. Cardiomyopathy is anticipated, detected, and treated early with afterload reduction. Oxygen saturation monitoring, noninvasive positive pressure ventilation and cough assist devices are routinely used. Other medical issues such as osteoporosis, gastrointestinal and urinary symptoms are addressed. Current and future therapies directed at prolonging the lifespan of those with DMD will result in further increases in this adult population with special needs and concerns. These needs are best addressed in a multidisciplinary clinic.

"My son is still walking": stages of receptivity to discussions of advance care planning among parents of sons with Duchenne muscular dystrophy

Duchenne muscular dystrophy is an inherited progressive neuromuscular disease that generally results in death by early adulthood. Because of its life-threatening nature, discussions of advance care planning are extremely relevant to families with affected children and adolescents. Seventeen parents of sons with Duchenne muscular dystrophy were interviewed about their attitudes, experiences, and the nature of their discussions about these topics. Parents showed a lack of familiarity with and experience communicating about advance care planning. They also discussed opportunities for communication that centered on transitional life events. Parents appeared to vacillate between hope for future treatments, avoidance of emotionally difficult aspects of the disease, and presence with the fullness of life's experiences. These data suggest a model for future research in which windows of opportunity for discussion may exist as sons are approaching significant transitional milestones and parents are able to see the world through a lens of "presence."