Consensus-Based Care Recommendations for Pulmonologists Treating Adults with Myotonic Dystrophy Type 1

The Role of Cognition, Affective Symptoms, and Apathy in Treatment Adherence with Noninvasive Home Mechanical Ventilation in Myotonic Dystrophy

Background

Chronic respiratory failure often occurs in myotonic dystrophy type 1 (DM1) and can be treated with noninvasive home mechanical ventilation (HMV). Treatment adherence with HMV is often suboptimal in patients with DM1, but the reasons for that are not well understood.

Objective

The aim of this exploratory study was to gain insight in the prevalence of mild cognitive impairment, affective symptoms, and apathy and to investigate their role in HMV treatment adherence in DM1.

Methods

The Montreal Cognitive Assessment (MoCA), the Hospital Anxiety and Depression Scale (HADS), and the Apathy Evaluation Scale (AES) were used to assess cognition, affective symptoms, and apathy in DM1 patients that use HMV. Patients with low treatment adherence (average daily use HMV <5 h or <80% of the days) were compared with patients with high treatment adherence (average daily use of HMV≥5 h and ≥80% of the days).

Results

Sixty patients were included. Abnormal scores were found in 40% of the total group for the MoCA, in 72-77% for the AES, and in 18% for HADS depression. There was no difference between the high treatment adherence group (n = 39) and the low treatment adherence group (n = 21) for the MoCA, AES, and HADS depression. The HADS anxiety was abnormal in 30% of the total group, and was significantly higher in the low treatment adherence group (p = 0.012). Logistic regression analysis revealed that a higher age and a higher BMI were associated with a greater chance of high treatment adherence.

Conclusions

This exploratory study showed that cognitive impairment and apathy are frequently present in DM1 patients that use HMV, but they are not associated with treatment adherence. Feelings of anxiety were associated with low treatment adherence. Higher age and higher BMI were associated with high treatment adherence with HMV.

Role of respiratory characteristics in treatment adherence with noninvasive home mechanical ventilation in myotonic dystrophy type 1, a retrospective study

Chronic respiratory insufficiency is common in patients with myotonic dystrophy type 1 (DM1) and can be treated with noninvasive home mechanical ventilation (HMV). HMV is not always tolerated well resulting in low treatment adherence. We aimed to analyze if baseline respiratory characteristics such as pulmonary function, level of pCO2 and presence of sleep apnea are associated with HMV treatment adherence in DM1 patients. Pulmonary function testing, polysomnography and blood gas measurement data of DM1 patients were retrospectively collected. Initiation of HMV and treatment adherence after one year was documented. Patients with low treatment adherence (average daily use of HMV <5 h) were grouped with patients that discontinued HMV and compared with patients with high treatment adherence (average daily use of HMV >5 h). HMV was initiated in 101 patients. After one year, 58 patients had low treatment adherence. There were no differences between the low and high treatment adherence group regarding the respiratory characteristics. None of the included predictors (gender, age, body mass index, cytosine-thymine-guanine repeat length, FVC, daytime pCO2, bicarbonate, nighttime pCO2, nighttime base excess, apnea-hypopnea index and mean saturation during sleep) was able to significantly predict high treatment adherence. In conclusion, the respiratory characteristics are not associated with treatment adherence with HMV in DM1 patients and cannot be used to identify patients at risk for low HMV treatment adherence.

Retraction: Ferrari Aggradi, CR, Falcier, E, Lizio, A, et al. Assessment of respiratory function and need for non-invasive ventilation in a cohort of patients with myotonic dystrophy type 1 followed at one single expert centre. The Clinical Respiratory Journal. 2022; 1- 13. (https://doi.org/10.1111/crj.13516)

The above article, published online on 27 June 2022 in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the authors, the journal Editors in Chief, Professor Paul Jones and Professor Yuanlin Song and John Wiley and Sons Ltd. The retraction has been agreed due to an error with the publisher and author which caused a duplicate of the article to be published on 27 June 2022. The correct version of the article is to be found at: Carola R. Ferrari Aggradi, Elisa Falcier, Andrea Lizio, Alice Pirola, Jacopo Casiraghi, Alice Zanolini, Elena Carraro, Luca Mauro, Fabrizio Rao, Elisabetta Roma, Antonino Iannello, Elisa De Mattia, Andrea Barp, Sara Lupone, Valentina Gatti, Cristina Italiano, Valeria A. Sansone, "Assessment of Respiratory Function and Need for Noninvasive Ventilation in a Cohort of Patients with Myotonic Dystrophy Type 1 Followed at One Single Expert Center", Canadian Respiratory Journal, vol. 2022, Article ID 2321909, 11 pages, 2022. https://doi.org/10.1155/2022/2321909.

The current status of medical care for myotonic dystrophy type 1 in the national registry of Japan

INTRODUCTION/AIMS

Myotonic dystrophy (DM) is a systemic disease with multiple organ complications, making the standardization of medical care a challenge. We analyzed data from Japan's national registry to clarify the current treatment patterns and demographic features of Japanese DM patients.

METHODS

Using the Japanese National Registry of Muscular Dystrophy (Remudy), we analyzed medical care practice for the multisystemic issues associated with adult DM type 1 patients, excluding congenital DM.

RESULTS

We included 809 patients with a median age of 44.2 years. Among these patients, 15.8% used ventilators; 31.7% met the index considered at risk for sudden death due to cardiac conduction defects (PR interval over 240 milliseconds or QRS duration over 120 milliseconds) and 2.8% had implanted cardiac devices. Medication for heart failure was prescribed to 9.6% of patients. Overall, 21.2% of patients had abnormal glucose metabolism, of whom 42.9% were treated with oral medications. Among the oral medications, dipeptidyl peptidase-4 inhibitors were the most common. Cancers were observed in 3.7% of the patients, and endometrial and breast cancers were dominant. Mexiletine was prescribed for myotonia in 1.9% of the patients, and only 1% of the patients received medication for daytime sleepiness.

DISCUSSION

This study shows difference in treatment patterns for DM1 in Japan compared with other countries, such as lower rates of use of implantable cardiac devices and higher rates of ventilator use. These data may be useful in discussions aimed at standardizing medical care for patients with DM.

Myotonic dystrophy type 1: A comparison between the adult- and late-onset subtype

INTRODUCTION/AIMS

Although the extent of muscle weakness and organ complications has not been well studied in patients with late-onset myotonic dystrophy type 1 (DM1), adult-onset DM1 is associated with severe muscle involvement and possible life-threatening cardiac and respiratory complications. In this study we aimed to compare the clinical phenotype of adult-onset vs late-onset DM1, focusing on the prevalence of cardiac, respiratory, and muscular involvement.

METHODS

Data were prospectively collected in the Dutch DM1 registry.

RESULTS

Two hundred seventy-five adult-onset and 66 late-onset DM1 patients were included. Conduction delay on electrocardiogram was present in 123 of 275 (45%) adult-onset patients, compared with 24 of 66 (36%) late-onset patients (P = .218). DM1 subtype did not predict presence of conduction delay (odds ratio [OR] 0.706; confidence interval [CI] 0.405 to 1.230, P = .219). Subtype did predict indication for noninvasive ventilation (NIV) (late onset vs adult onset: OR, 0.254; CI, 0.104 to 0.617; P = .002) and 17% of late-onset patients required NIV compared with 40% of adult-onset patients. Muscular Impairment Rating Scale (MIRS) scores were significantly different between subtypes (MIRS 1 to 3 in 66% of adult onset vs 100% of late onset [P < .001]), as were DM1-activ^C scores (67 ± 21 in adult onset vs 87 ± 15 in late onset; P < .001).

DISCUSSION

Although muscular phenotype was milder in late-onset compared with adult-onset DM1, the prevalence of conduction delay was comparable. Moreover, subtype was unable to predict the presence of cardiac conduction delay. Although adult-onset patients had an increased risk of having an NIV indication, 17% of late-onset patients required NIV. Despite different muscular phenotypes, screening for multiorgan involvement should be equally thorough in late-onset as in adult-onset DM1.

Dyspnea assessment in myotonic dystrophy type 1

In myotonic mystrophy type 1 (DM1), combining respiratory symptom screening and respiratory function testing, is crucial to identify the appropriate time for ventilatory support initiation. Dyspnea has been little investigated in DM1. To provide a multidimensional description of dyspnea, questionnaires assessing dyspnea were administered to 34 consecutive adult patients with DM1 (median (25th-75th centile) age of 36 (28-49), Vital Capacity (VC) of 74 (64-87)% of predicted value). Dyspnea scores were low whatever the questionnaire used: Multidimensional Dyspnea Profile score of 2(0-4.7)/50 for dyspnea sensory descriptor and of 0 (0-4.7)/60 for the emotional descriptor, Visual Analogue Scale score of 0 (0-0)/10 in sitting and supine position and Borg score after six-minute walk test (6MWT) of 2.2 (1.8-4.2)/10. Eleven patients (32%) reported disabling dyspnea in daily living (modified Medical Research Council (mMRC) score ≥ 2). In comparison with patients with mMRC score < 2, patients with mMRC score ≥ 2 had a more severe motor handicap (Muscular Impairment Rating score of 4.0 (4.0-4.0) vs 3.0 (2.0-3.5), p<0.01), a lower 6MWT distance (373 (260-424) vs 436 (346-499)m, p = 0.03) and a lower VC (64 (48-74)% vs 75 (69-89)%, p = 0.02). These data suggest that the mMRC scale might be an easy-to-use and useful tool to assess dyspnea in daily living in DM1 patients. However, the interest of integrating the mMRC dyspnea scale in clinical practice to guide therapeutic management of DM1 patients remains to be assessed in further studies.

Development of prediction models based on respiratory assessments to determine the need for non-invasive ventilation in patients with myotonic dystrophy type 1

INTRODUCTION

Myotonic dystrophy type 1 is a slowly progressive, multisystem, autosomal dominant disorder, in which the impairments of respiratory systems represent one of the main causes of death.

OBJECTIVE

The aim of our study is to develop prediction models to identify the most appropriate test(s) providing indication for NIV.

METHODS

DM1 patients attending the NEMO Clinical Center (Milan) between January 2008 and July 2020, who had been subjected to a complete battery of respiratory tests, were retrospectively recruited. Demographic, clinical, and anthropometric characteristics were collected, as well as arterial blood gas (ABG) analysis, spirometry, respiratory muscle strength, cough efficacy, and nocturnal oximetry as respiratory assessments. Patients were stratified in those requiring NIV and those with normal respiratory function.

RESULTS

Out of 151 DM1 patients (median age: 44 years [35.00-53.00]; male/female ratio: 0.80 (67/84)), 76 had an indication for NIV initiation (50.33%). ABG, spirometry, and nocturnal oximetry prediction models resulted in an excellent discriminatory ability in distinguishing patients who needed NIV from those who did not (AUC of 0.818, 0.808, and 0.935, respectively). An easy-to-use calculator was developed to automatically determine a score of NIV necessity based on the prediction equations generated from each aforementioned prediction model.

CONCLUSIONS

The proposed prediction models may help to identify which patients are at a higher risk of requiring ventilator support and therefore help in defining individual management plans and criteria for specific interventions early in the disease course.

Gray Matter Abnormalities in Myotonic Dystrophy Type 1: A Voxel-Wise Meta-Analysis

Background

A growing number of voxel-based morphometry (VBM) studies have demonstrated widespread gray matter (GM) abnormalities in myotonic dystrophy type 1 (DM1), but the findings are heterogeneous. This study integrated previous VBM studies to identify consistent GM changes in the brains of patients with DM1.

Methods

Systematic retrieval was conducted in Web of Science, Pubmed, and Embase databases to identify VBM studies that met the inclusion requirements. Data were extracted. The Seed-based d Mapping with Permutation of Subject Images (SDM-PSI) software was used for meta-analysis of voxel aspects.

Results

A total of eight VBM studies were included, including 176 patients with DM1 and 198 healthy controls (HCs). GM volume in patients with DM1 was extensively reduced compared with HCs, including bilateral rolandic operculum, bilateral posterior central gyrus, bilateral precentral gyrus, right insula, right heschl gyrus, right superior temporal gyrus, bilateral supplementary motor area, bilateral middle cingulate gyrus/paracingulate gyrus, left paracentral lobule, and bilateral caudate nucleus. Meta-regression analysis found that regional GM abnormalities were associated with disease duration and Rey-Osterrieth Complex Figure (ROCF)-recall scores.

Conclusion

DM1 is not only a disease of muscle injury but also a multisystem disease involving brain motor and neuropsychiatric regions, providing a basis for the pathophysiological mechanism of DM1.

Assessment of Respiratory Function and Need for Noninvasive Ventilation in a Cohort of Patients with Myotonic Dystrophy Type 1 Followed at One Single Expert Center

Introduction

Respiratory insufficiency is one of the main causes of death in myotonic dystrophy type 1 (DM1). Although there is general consensus that these patients have a restrictive ventilatory pattern, hypoventilation, chronic hypercapnia, and sleep disturbances, the prevalence of respiratory disease and indication for the effects of noninvasive ventilation (NIV) need to be further explored.

Objectives

To describe respiratory function and need for NIV at baseline and over time in a cohort of adult patients with DM1.

Methods

A total of 151 adult patients with DM1 were subjected to arterial blood gas analysis, sitting and supine forced vital capacity (FVC), peak cough expiratory flow (PCEF), nocturnal oximetry, and maximal inspiratory pressure and expiratory pressure (MIP/PEP).

Results

On first assessment, 84 of 151 had normal respiratory function (median age: 38 years, median BMI: 23.9, and median disease duration: 11 years); 67 received an indication to use NIV (median age: 49 years, median BMI: 25,8, and median disease duration: 14 years). After a median time of 3.85 years, 43 patients were lost to follow-up; 9 of 84 required NIV; only 17 of 67 with the new NIV prescription were adherent.

Conclusions

We provide additional data on the natural history of respiratory function decline and treatment adherence in a relatively large cohort of well-characterized patients with DM1. A high proportion (28%) was lost to follow-up. A minority (11%) required NIV, and only 25% were treatment adherent, irrespective of specific demographics and respiratory features. Our results also confirm previous findings, showing that age, disease duration, and higher BMIs are predisposing factors for respiratory impairment.

Myotonic Dystrophies: A Genetic Overview

Myotonic dystrophies (DM) are the most common muscular dystrophies in adults, which can affect other non-skeletal muscle organs such as the heart, brain and gastrointestinal system. There are two genetically distinct types of myotonic dystrophy: myotonic dystrophy type 1 (DM1) and myotonic dystrophy type 2 (DM2), both dominantly inherited with significant overlap in clinical manifestations. DM1 results from CTG repeat expansions in the 3'-untranslated region (3'UTR) of the DMPK (dystrophia myotonica protein kinase) gene on chromosome 19, while DM2 is caused by CCTG repeat expansions in intron 1 of the CNBP (cellular nucleic acid-binding protein) gene on chromosome 3. Recent advances in genetics and molecular biology, especially in the field of RNA biology, have allowed better understanding of the potential pathomechanisms involved in DM. In this review article, core clinical features and genetics of DM are presented followed by a discussion on the current postulated pathomechanisms and therapeutic approaches used in DM, including the ones currently in human clinical trial phase.

Current Treatment Options for Patients with Myotonic Dystrophy Type 2

Purpose of the review

Myotonic dystrophy types 1 and 2 are frequent forms of muscular dystrophies in adulthood. Their clinical differences need to be taken into account for the most appropriate treatment of patients. The aim of this article is to provide an overview on the current and upcoming therapeutic options for patients with myotonic dystrophy type 2 (DM2).

Recent findings

At the moment, no disease-modifying therapies are available for DM2; next-generation therapies may however be available in the near future. In the meanwhile, the symptomatic management of patients has greatly improved, thank to the production of consensus-based standards of care and the growing evidence of efficacy of anti-myotonic drugs, promising employment of cannabinoids for symptom’s relief, regular monitoring, and early detection of treatable extra-muscular manifestations.

Summary

The treatment of DM2 is currently symptomatic and relies on the coordinated intervention of a multidisciplinary team. It remains to be determined whether upcoming causal therapies for myotonic dystrophy type 1 will be applicable also in DM2.

Hypoventilation syndrome in neuromuscular disorders

PURPOSE OF REVIEW

Hypoventilation syndrome in neuromuscular disorders (NMDs) is primarily due to respiratory muscle weakness and results in increased morbidity and mortality. This article highlights current aspects of neuromuscular hypoventilation syndrome, including pathophysiology, clinical symptoms, assessment, respiratory involvement in various NMD, and causal and symptomatic treatments with an emphasis on recent research and advances.

RECENT FINDINGS AND SUMMARY

New therapeutic agents have been developed within the last years, proving a positive effect on respiratory system. Symptomatic therapies, including mechanical ventilation and cough assistance approaches, are important in NMD and respiratory muscle training may have benefit in strengthening respiratory muscles and should be offered patients with respiratory muscle weakness the same way as physiotherapy. Correct respiratory assessments and their correct interpretation are hallmarks for early diagnosis of hypoventilation syndrome and treatment.

Assessment of self-reported and objective daytime sleepiness in adult-onset myotonic dystrophy type 1

STUDY OBJECTIVES

Excessive daytime sleepiness (EDS) in myotonic dystrophy type 1 (DM1) is mostly of central origin but it may coexist with sleep-related breathing disorders. However, there is no consensus on the sleep protocols to be used, assessments vary and only a minority of patients are regularly tested or are on treatment for EDS. Our study presents data on self-reported and objective EDS in adult-onset DM1.

METHODS

63 adult-onset DM1 patients were subjected to EDS-sleep assessments (polysomnography, PSG; Multiple Sleep Latency Test, MSLT; Epworth Sleepiness Scale, ESS. Correlation coefficients were computed to assess the relationship between sleep and sleepiness test results, fatigue, quality of life.

RESULTS

33% and 48% of patients had EDS based respectively on the ESS and the MSLT with a low concordance between these tests (k = 0.19). Thirteen patients (20%) displayed 2 or more sleep-onset REM periods on MSLT. Patients having EDS by MSLT had a shorter disease duration (p<0.05), higher total sleep time, sleep efficiency and lower WASO (Wake After Sleep Onset) on PSG. Patients with self-reported EDS reported significantly higher fatigue score compared to patients without EDS (p<0.05). No other difference was found in demographic, clinical and respiratory features.

CONCLUSIONS

EDS test results are contradictory making treatment options difficult. Combining quantitative tests and self-reported scales may facilitate physicians in planning EDS care with patients and families.

New developments in myotonic dystrophies from a multisystemic perspective

PURPOSE OF REVIEW

The multisystemic involvement of myotonic dystrophies (DMs) intricates disease monitoring, patients' care and trial design. This update of the multifaceted comorbidities observed in DMs aims to assist neurologists in the complex management of patients and to encourage further studies for still under-investigated aspects of the disease.

RECENT FINDINGS

We reviewed the most recent studies covering pathogenesis and clinical aspects of extra-muscular involvement in DM1 and DM2. The largest body of evidence regards the cardiac and respiratory features, for which experts' recommendations have been produced. Gastrointestinal symptoms emerge as one of the most prevalent complaints in DMs. The alteration of insulin signaling pathways, involved in gastrointestinal manifestations, carcinogenesis, muscle function, cognitive and endocrinological aspects, gain further relevance in the light of recent evidence of metformin efficacy in DM1. Still, too few studies are performed on large DM2 cohorts, so that current recommendations mainly rely on data gathered in DM1 that cannot be fully translated to DM2.

SUMMARY

Extra-muscular manifestations greatly contribute to the overall disease burden. A multidisciplinary approach is the key for the management of patients. Consensus-based recommendations for DM1 and DM2 allow high standards of care but further evidence are needed to implement these recommendations.

Noninvasive Home Mechanical Ventilation in Adult Myotonic Dystrophy Type 1: A Systematic Review

INTRODUCTION

Chronic hypercapnic respiratory failure induces considerable morbidity and mortality in patients with myotonic dystrophy type 1 (DM1). This study systematically reviews the effects of noninvasive home mechanical ventilation (HMV) on gas exchange, quality of life, survival, and compliance in DM1 patients.

METHODS

A systematic Medline and Embase search was performed (January 1995 to January 2020). Records were screened for eligibility criteria, data were extracted from included studies, and risk of bias was assessed. We present findings mainly using a narrative synthesis.

RESULTS

Twenty-eight relevant full-text articles were screened for eligibility criteria. Nine studies were included. Randomized controlled trials were not found. Studies had either an observational (n = 8) or interventional (n = 1) design. In the pooled data analysis, HMV showed to improve mean oxygen saturation with 4.8% and decreased mean carbon dioxide values with 3 mm Hg. Compliance varied widely between studies, from no use to more than 12 h per day. Quality of life was not studied extensively, but some studies reported positive effects of HMV on symptoms of chronic respiratory failure. HMV may improve survival in DM1 patients with chronic hypercapnic respiratory failure.

CONCLUSION

This review shows that HMV can improve gas exchange and relieve symptoms with a possible survival benefit in DM1 patients with chronic hypercapnic respiratory failure. Future studies should focus on developing strategies to optimize the timing of HMV initiation and to promote compliance.

New Insights in Adherence and Survival in Myotonic Dystrophy Patients Using Home Mechanical Ventilation

BACKGROUND

Non-invasive home mechanical ventilation (HMV) is a complex treatment in myotonic dystrophy type 1 (DM1) patients, due to a presumed poor adherence, variable symptom improvement, and uncertainty regarding survival benefits.

OBJECTIVES

We aimed to investigate indications, adherence to HMV and its effects on mortality in a large cohort of DM1 patients.

METHODS

In this retrospective cohort study, we evaluated 224 DM1 patients. Different groups based on hypercapnia and HMV treatment were compared. Cox regression analyses were performed to compare mortality between different defined groups.

RESULTS

224 patients were analysed of whom 111 started non-invasive HMV. Indications were daytime hypercapnia (n = 75), only nocturnal hypercapnia (n = 33), or other reasons (n = 3). Adequate adherence (≥4 h/night) was found in 84.9% of patients. Adequate ventilation was reached in 86.5% of patients. In 33 patients (29.7%), HMV was stopped prematurely due to not reaching patients' expectations on symptom relief or treatment burden (n = 22), or intolerance (n = 8), or other reasons (n = 3). HMV did not improve survival in daytime hypercapnic patients (p = 0.61) nor in nocturnal hypercapnia patients compared to daytime hypercapnia (p = 0.21). Significant survival benefits after starting HMV were found for patients with HMV adherence ≥5 h/24 h compared to patients who used HMV less.

CONCLUSION

In this large cohort, daytime hypercapnia is the main reason for starting HMV, which is well tolerated and used. Mortality is not associated with the reason why HMV was started, but once started, patients with ≥5 h/24 h adherence have significantly better survival compared to patients who use it less.