Prevalence and incidence of neuromuscular conditions in the UK between 2000 and 2019: A retrospective study using primary care data

A retrospective observational study on characteristics, treatment patterns, and healthcare resource use of patients with myasthenia gravis in England

Background

There are limited data on the real-world healthcare resource use (HCRU) and management costs of myasthenia gravis (MG) in England.

Objective

This study aims to assess the burden of disease for patients with MG in England.

Design

A retrospective, observational cohort study of adult patients diagnosed with MG, using data from the Hospital Episode Statistics data warehouse.

Methods

Patients with a first-ever recorded diagnosis of MG between 30 June 2015 and 30 June 2020 were followed up until 30 June 2021 or death, whichever occurred first. Post-diagnosis patient characteristics, treatment patterns, HCRU, and costs were described. Costs were evaluated using National Health Service reference costs.

Results

A total of 9087 patients with a median follow-up time of 2.9 years (range, 1.7-4.3 years) were included. The mean age at diagnosis was 66.5 years and 53% of the patients were male. A large proportion of patients (72.8%) were admitted as inpatients during follow-up with a mean number of 1.3 admissions. Patients hospitalized for MG-related complications spent a mean of 9.7 days per patient-year in the hospital. During follow-up, 599 (6.6% of the total cohort) and 163 (1.8%) patients had a record of rescue therapy with intravenous immunoglobulin (IVIg) and plasma exchange (PLEX), respectively. Rituximab was administered to 81 (0.9%) patients and 268 (2.9%) patients underwent thymectomy. In those patients receiving rescue therapy or rituximab, >10% received at least three cycles of the same treatment. The average annual cost of hospital admissions across all patients treated with IVIg, PLEX, and rituximab were £907,072, £689,979, and £146,726, respectively.

Conclusion

A majority of MG patients required hospitalization or accident and emergency attendance, resulting in high HCRU and costs. A subset of patients required rescue therapy (including IVIg and PLEX), rituximab administration, ventilation, or thymectomy.

Global carrier frequency and predicted genetic prevalence of patients with pathogenic sequence variants in autosomal recessive genetic neuromuscular diseases

Genetic neuromuscular diseases are clinically and genetically heterogeneous genetic disorders that primarily affect the peripheral nerves, muscles, and neuromuscular junctions. This study aimed to identify pathogenic variants, calculate carrier frequency, and predict the genetic prevalence of autosomal recessive neuromuscular diseases (AR-NMDs). We selected 268 AR-NMD genes and analyzed their genetic variants sourced from the gnomAD database. After identifying the pathogenic variants using an algorithm, we calculated the carrier frequency and predicted the genetic prevalence of AR-NMDs. In total, 10,887 pathogenic variants were identified, including 3848 literature verified and 7039 manually verified variants. In the global population, the carrier frequency of AR-NMDs is 32.9%, with variations across subpopulations ranging from 22.4% in the Finnish population to 36.2% in the non-Finnish European population. The predicted genetic prevalence of AR-NMDs was estimated to be 24.3 cases per 100,000 individuals worldwide, with variations across subpopulations ranging from 26.5 to 41.4 cases per 100,000 individuals in the Latino/Admixed American and the Ashkenazi Jewish populations, respectively. The AR-NMD gene with the highest carrier frequency was GAA (1.3%) and the variant with the highest allele frequency was c.-32-13 T>G in GAA with 0.0033 in the global population. Our study revealed a higher-than-expected frequency of AR-NMD carriers, constituting approximately one-third of the global population, highlighting ethnic heterogeneity in genetic susceptibility.

Pooling of primary care electronic health record (EHR) data on Huntington's disease (HD) and cancer: establishing comparability of two large UK databases

OBJECTIVES

To explore whether UK primary care databases arising from two different software systems can be feasibly combined, by comparing rates of Huntington's disease (HD, which is rare) and 14 common cancers in the two databases, as well as characteristics of people with these conditions.

DESIGN

Descriptive study.

SETTING

Primary care electronic health records from Clinical Practice Research Datalink (CPRD) GOLD and CPRD Aurum databases, with linked hospital admission and death registration data.

PARTICIPANTS

4986 patients with HD and 1 294 819 with an incident cancer between 1990 and 2019.

PRIMARY AND SECONDARY OUTCOME MEASURES

Incidence and prevalence of HD by calendar period, age group and region, and annual age-standardised incidence of 14 common cancers in each database, and in a subset of 'overlapping' practices which contributed to both databases. Characteristics of patients with HD or incident cancer: medical history, recent prescribing, healthcare contacts and database follow-up.

RESULTS

Incidence and prevalence of HD were slightly higher in CPRD GOLD than CPRD Aurum, but with similar trends over time. Cancer incidence in the two databases differed between 1990 and 2000, but converged and was very similar thereafter. Participants in each database were most similar in terms of medical history (median standardised difference, MSD 0.03 (IQR 0.01-0.03)), recent prescribing (MSD 0.06 (0.03-0.10)) and demographics and general health variables (MSD 0.05 (0.01-0.09)). Larger differences were seen for healthcare contacts (MSD 0.27 (0.10-0.41)), and database follow-up (MSD 0.39 (0.19-0.56)).

CONCLUSIONS

Differences in cancer incidence trends between 1990 and 2000 may relate to use of a practice-level data quality filter (the 'up-to-standard' date) in CPRD GOLD only. As well as the impact of data curation methods, differences in underlying data models can make it more challenging to define exactly equivalent clinical concepts in each database. Researchers should be aware of these potential sources of variability when planning combined database studies and interpreting results.

Living with Dysphagia: A Survey Exploring the Experiences of Adults Living with Neuromuscular Disease and their Caregivers in the United Kingdom

Background

Dysphagia is common in adults living with neuromuscular disease (NMD). Increased life expectancy, secondary to improvements in standards of care, requires the recognition and treatment of dysphagia with an increased priority. Evidence to support the establishment of healthcare pathways is, however, lacking. The experiences of people living with NMD (pplwNMD) and their caregivers are valuable to guide targeted, value-based healthcare.

Objective

To generate preliminary considerations for neuromuscular dysphagia care and future research in the United Kingdom, based on the experiences of those living with, or caring for, people with NMD.

Methods

Two surveys (one for adults living with NMD and dysphagia, and a second for caregivers) were co-designed with an advisory group of people living with NMD. Surveys were electronically distributed to adults living with NMD and their caregivers between 18th May and 26th July 2020. Distribution was through UK disease registries, charity websites, newsletters, and social media.

Results

Adults living with NMD receive little information or education that they are likely to develop swallowing difficulties. Most respondents report wanting this information prior to developing these difficulties. Difficulties with swallowing food and medication are common in this group, and instrumental assessment is considered a helpful assessment tool. Both adults living with NMD and caregivers want earlier access to neuromuscular swallowing specialists and training in how best to manage their difficulties.

Conclusions

Improvement is needed in the dysphagia healthcare pathway for adults living with NMD to help mitigate any profound physical and psychological consequences that may be caused by dysphagia. Education about swallowing difficulties and early referral to a neuromuscular swallowing specialist are important to pplwNMD and their caregivers. Further research is required to better understand the experiences of pplwNMD and their caregivers to inform the development of dysphagia healthcare pathways.

Participant experiences of guided self-help Acceptance and Commitment Therapy for improving quality of life in muscle disease: a nested qualitative study within the ACTMus randomized controlled trial

Introduction

In adults, muscle disease (MD) is typically a chronic long-term condition that can lead to a reduced quality of life (QoL). Previous research suggests that a psychological intervention, in particular Acceptance and Commitment Therapy (ACT), may help improve QoL for individuals living with chronic conditions such as MD.

Methods

This nested qualitative study was incorporated within a randomized controlled trial which evaluated a guided self-help ACT intervention for people living with MD to explore their experiences of the intervention. Semi-structured interviews (n = 20) were conducted with those who had received ACT. Data were analyzed via thematic analysis.

Results

There were four overarching themes. (1) Views on whether therapy sessions would help with a medical condition: participants' expectations regarding ACT varied. Some participants were skeptical about mindfulness. (2) I was able to look at things in a different way: participants described increased meaningful activity, greater awareness of thoughts and emotions and acceptance or adaptation to mobility problems. Some described improvement in the quality of relationships and a sense of feeling free. (3) Treating the body and the mind together: following the intervention participants noted that a holistic approach to healthcare is beneficial. (4) Intervention delivery: The remote delivery was generally seen as helpful for practical reasons and allowed participants to speak openly. Participants voiced a need for follow-up sessions.

Discussion

Overall, the intervention was experienced as acceptable. Suggested improvements included de-emphasizing the role of mindfulness and adding follow-up sessions.

Epidemiology of the idiopathic inflammatory myopathies

The idiopathic inflammatory myopathies (IIMs) are a heterogeneous group of systemic autoimmune diseases that affect the skeletal muscles and can also involve the skin, joints, lungs and heart. The epidemiology of IIM is obscured by changing classification criteria and the inherent shortcomings of case identification using healthcare record diagnostic coding. The incidence of IIM is estimated to range from 0.2 to 2 per 100,000 person-years, with prevalence from 2 to 25 per 100,000 people. Although the effects of age and gender on incidence are known, there is only sparse understanding of ethnic differences, particularly in indigenous populations. The incidence of IIM has reportedly increased in the twenty-first century, but whether this is a genuine increase is not yet known. Understanding of the genetic risk factors for different IIM subtypes has advanced considerably. Infections, medications, malignancy and geography are also commonly identified risk factors. Potentially, the COVID-19 pandemic has altered IIM incidence, although evidence of this occurrence is limited to case reports and small case series. Consideration of the current understanding of the epidemiology of IIM can highlight important areas of interest for future research into these rare diseases.

Hereditary Neuropathies

OBJECTIVE

This article provides an overview of hereditary neuropathies, describes the different hereditary neuropathy subtypes and the clinical approach to differentiating between them, and summarizes their clinical management.

LATEST DEVELOPMENTS

Increasingly available clinical genetic testing has broadened the clinical spectrum of hereditary neuropathy subtypes and demonstrated a significant overlap of phenotypes associated with a single gene. New subtypes such as SORD -related neuropathy and CANVAS (cerebellar ataxia, neuropathy, vestibular areflexia syndrome) have emerged. The optimization of clinical management has improved gait and motor function in the adult and pediatric populations. Novel therapeutic approaches are entering clinical trials.

ESSENTIAL POINTS

Hereditary neuropathies constitute a spectrum of peripheral nerve disorders with variable degrees of motor and sensory symptoms, patterns of involvement, and clinical courses.

Refining Incidence and Characteristics of Inflammatory Myopathies: A Quadruple-Source Capture-Recapture Survey Using the 2017 European League Against Rheumatism/American College of Rheumatology Classification Criteria

OBJECTIVE

Inflammatory myopathies (IM), characterized by muscle inflammation and weakness, are rare systemic diseases. Our previous study estimated an IM incidence rate of 7.98 cases per million people per year (95% confidence interval 7.38-8.66) and highlighted important variations that were likely because of methodologic issues rather than true epidemiologic differences. In this study, we aimed to refine the incidence of IM, using the 2017 European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) classification criteria for IM and a quadruple-source capture-recapture method during a 6-year period in Alsace, France, a region with a population of 2 million having benefits of good access to health care and accredited IM referral centers.

METHODS

Clinical data of potential IM patients were obtained from 4 sources (general practitioners and community specialists, public and private hospital records, public and private laboratories, and archives from the pathology department). Patients residing in Alsace and who fulfilled the 2017 EULAR/ACR criteria for IM between January 1, 2006, and January 1, 2013, were included. We corrected potentially incomplete ascertainment of cases with capture-recapture analyses. We studied both spatial and temporal distributions of incidence of IM. We also assessed systemic manifestations of the disease.

RESULTS

Our review of 1,742 potential cases identified 106 patients with IM. No spatial or temporal heterogeneity was observed. Use of log-linear models showed an estimated 14.9 additional missed cases. Thus, the incidence rate of IM was 8.22 new cases per million inhabitants per year (95% confidence interval 6.76-9.69). Extramuscular manifestations other than dermatomyositis rash were frequently recorded.

CONCLUSION

The stringent methodology used in our study provides an accurate estimation of the incidence of IM. This study also demonstrates, in a population-based cohort, the systemic nature of IM.

Real-world evidence from the first online healthcare analytics platform-Livingstone. Validation of its descriptive epidemiology module

Incidence and prevalence are key epidemiological determinants characterizing the quantum of a disease. We compared incidence and prevalence estimates derived automatically from the first ever online, essentially real-time, healthcare analytics platform-Livingstone-against findings from comparable peer-reviewed studies in order to validate the descriptive epidemiology module. The source of routine NHS data for Livingstone was the Clinical Practice Research Datalink (CPRD). After applying a general search strategy looking for any disease or condition, 76 relevant studies were first retrieved, of which 10 met pre-specified inclusion and exclusion criteria. Findings reported in these studies were compared with estimates produced automatically by Livingstone. The published reports described elements of the epidemiology of 14 diseases or conditions. Lin's concordance correlation coefficient (CCC) was used to evaluate the concordance between findings from Livingstone and those detailed in the published studies. The concordance of incidence values in the final year reported by each study versus Livingstone was 0.96 (95% CI: 0.89-0.98), whilst for all annual incidence values the concordance was 0.93 (0.91-0.94). For prevalence, concordance for the final annual prevalence reported in each study versus Livingstone was 1.00 (0.99-1.00) and for all reported annual prevalence values, the concordance was 0.93 (0.90-0.95). The concordance between Livingstone and the latest published findings was near perfect for prevalence and substantial for incidence. For the first time, it is now possible to automatically generate reliable descriptive epidemiology from routine health records, and in near-real time. Livingstone provides the first mechanism to rapidly generate standardised, descriptive epidemiology for all clinical events from real world data.

Real world study on prevalence, treatment and economic burden of myasthenia gravis in Italy

The purpose of this study was to investigate the epidemiology, management, and economic burden of myasthenia gravis in settings of real clinical practice. The analysis used administrative databases covering around 12 million subjects across Italy and included all adult patients with hospitalization discharge diagnosis or active exemption code for myasthenia gravis or with ≥1 pyridostigmine prescription from 2011 to 2018. The estimated prevalence of myasthenia gravis during 2018 was in the range 13.5-29.3/100,000 people (depending on the criteria applied), corresponding to 8190-17,728 alive patients, when reproportioning data to the entire Italian population. Overall 4397 patients with myasthenia gravis (mean age 61.7 years, 46.6% males) were included. A large pyridostigmine use was observed (84.0%-46.8% from 1st to 3rd year of follow-up), followed by corticosteroids (54.5%-44.6% from 1st to 3rd year of follow-up) and non-steroidal immunosuppressants (16% over follow-up). Total direct healthcare costs for myasthenia gravis were 4-times higher than those of the general population (€3771 and €869, respectively), and up to 9-fold increased when considering patients with exacerbation (€7827). These findings showed the epidemiologic burden of myasthenia gravis and the complexity of the therapeutic management for the affected patients, with large use of treatments and elevated healthcare expenditures.

Prevalence of co-morbidity and history of recent infection in patients with neuromuscular disease: A cross-sectional analysis of United Kingdom primary care data

BACKGROUND

People with neuromuscular disease (NMD) experience a broader range of chronic diseases and health symptoms compared to the general population. However, no comprehensive analysis has directly quantified this to our knowledge.

METHODS

We used a large UK primary care database (Clinical Practice Research Datalink) to compare the prevalence of chronic diseases and other health conditions, including recent infections between 23,876 patients with NMD ever recorded by 2019 compared to 95,295 age-sex-practice matched patients without NMD. Modified Poisson regression estimated Prevalence Ratios (PR) to summarise the presence of the disease/condition ever (or for infections in 2018) in NMD patients versus non-NMD patients.

RESULTS

Patients with NMD had significantly higher rates for 16 of the 18 conditions routinely recorded in the primary care Quality and Outcomes Framework (QOF). Approximately 1-in-10 adults with NMD had ≥4 conditions recorded (PR = 1.39, 95%CI 1.33-1.45). Disparities were more pronounced at younger ages (18-49). For other (non-QOF) health conditions, significantly higher recorded levels were observed for rarer events (pulmonary embolism PR = 1.96 95%CI 1.76-2.18, hip fractures PR = 1.65 95%CI 1.47-1.85) as well as for more common primary care conditions (constipation PR = 1.52 95%CI 1.46-1.57, incontinence PR = 1.52 95%CI 1.44-1.60). The greatest co-morbidity burden was in patients with a myotonic disorder. Approximately 1-in-6 (17.1%) NMD patients had an infection recorded in the preceding year, with the risk of being hospitalised with an infection nearly double (PR = 1.92, 95%CI 1.79-2.07) compared to non-NMD patients.

CONCLUSION

The burden of chronic co-morbidity among patients with NMD is extremely high compared to the general population, and they are also more likely to present in primary and secondary care for acute events such as infections.

Epidemiology and treatment of myasthenia gravis: a retrospective study using a large insurance claims dataset in Germany

Myasthenia gravis (MG) is a rare, chronic autoimmune disease with symptoms of fluctuating muscular weakness and fatigability. The aim of this retrospective cohort study was to estimate the prevalence and incidence of MG in Germany, and to understand the burden of disease and treatment patterns, based on anonymized German claims data. Two patient samples were identified: (1) incident MG patients with newly onset disease between 2015 and 2019, and (2) prevalent MG patients in 2019. In total, 775 incident MG patients with a mean age of 66.9 years; and 1,247 prevalent MG patients with a mean age of 68.6 years were included. The prevalence for Germany was estimated to be 39.3/100,000 on 31/12/2019; the incidence in 2019 was 4.6 cases/100,000 persons. The 12-month mortality was 5.7. For 31.5% of the incident patients, no MG treatment was observed in the first year after the index date. Of all incident patients, 29.9% experienced an exacerbation, and 6.7% a myasthenic crisis during the observation. Our study indicates that a substantial proportion of MG patients remains untreated. Many MG patients still experience exacerbations / MG crises. MG seems to be associated with an excess mortality in comparison to the general non-MG population.

A meta-analysis on the prevalence of Charcot-Marie-Tooth disease and related inherited peripheral neuropathies

BACKGROUND

Charcot-Marie-Tooth disease and related inherited peripheral neuropathies (CMT&RIPNs) brings great suffering and heavy burden to patients, but its global prevalence rates have not been well described.

METHODS

We searched major English and Chinese databases for studies reporting the prevalence of CMT&RIPNs from the establishment of the databases to September 26, 2022. Based on the age, gender, study design, study region, and disease subtype, the included studies were correspondingly synthesized for meta-analyses on the overall prevalence and/or the subgroup analyses by using pool arcsine transformed proportions in the random-effects model.

RESULTS

Of the finally included 31 studies, 21 studied the whole age population and various types of CMT&RIPNs, and the others reported specific disease subtype(s) or adult or non-adult populations. The pooled prevalence was 17.69/100,000 (95% CI 12.32-24.33) for the whole age population and significantly higher for CMT1 [10.61/100,000 (95% CI 7.06-14.64)] than for other subtypes (P' < 0.001). Without statistical significance, the prevalence seemed higher in those aged ≥ 16 or 18 years (21.02/100,000) than in those aged < 16 years (16.13/100,000), in males (22.50/100,000) than in females (17.95/100,000), and in Northern Europe (30.97/100,000) than in other regions.

CONCLUSION

CMT&RIPNs are relatively more prevalent as CMT1 in the disease subtypes, and probably prevalent in older ages, males, and Northern Europe. More studies on the epidemiological characteristics of CMT&RIPNs with well-defined diagnosis criteria are needed to improve the prevalence evaluation and to arouse more attention to health care support.

Myositis in Germany: epidemiological insights over 15 years from 2005 to 2019

BACKGROUND

The medical care of patients with myositis is a great challenge in clinical practice. This is due to the rarity of these disease, the complexity of diagnosis and management as well as the lack of systematic analyses.

OBJECTIVES

Therefore, the aim of this project was to obtain an overview of the current care of myositis patients in Germany and to evaluate epidemiological trends in recent years.

METHODS

In collaboration with BARMER Insurance, retrospective analysis of outpatient and inpatient data from an average of approximately 8.7 million insured patients between January 2005 and December 2019 was performed using ICD-10 codes for myositis for identification of relevant data. In addition, a comparative analysis was performed between myositis patients and an age-matched comparison group from other populations insured by BARMER.

RESULTS

45,800 BARMER-insured individuals received a diagnosis of myositis during the observation period, with a relatively stable prevalence throughout. With regard to comorbidities, a significantly higher rate of cardiovascular disease as well as neoplasm was observed compared to the control group within the BARMER-insured population. In addition, myositis patients suffer more frequently from psychiatric disorders, such as depression and somatoform disorders. However, the ICD-10 catalogue only includes the specific coding of "dermatomyositis" and "polymyositis" and thus does not allow for a sufficient analysis of all idiopathic inflammatory myopathies subtypes.

CONCLUSION

The current data provide a comprehensive epidemiological analysis of myositis in Germany, highlighting the multimorbidity of myositis patients. This underlines the need for multidisciplinary management. However, the ICD-10 codes currently still in use do not allow for specific analysis of the subtypes of myositis. The upcoming ICD-11 coding may improve future analyses in this regard.

Modeling neuromuscular diseases in zebrafish

Neuromuscular diseases are a diverse group of conditions that affect the motor system and present some overlapping as well as distinct clinical manifestations. Although individually rare, the combined prevalence of NMDs is similar to Parkinson's. Over the past decade, new genetic mutations have been discovered through whole exome/genome sequencing, but the pathogenesis of most NMDs remains largely unexplored. Little information on the molecular mechanism governing the progression and development of NMDs accounts for the continual failure of therapies in clinical trials. Different aspects of the diseases are typically investigated using different models from cells to animals. Zebrafish emerges as an excellent model for studying genetics and pathogenesis and for developing therapeutic interventions for most NMDs. In this review, we describe the generation of different zebrafish genetic models mimicking NMDs and how they are used for drug discovery and therapy development.