Clinical and demographic factors and outcome of amyotrophic lateral sclerosis in relation to population ancestral origin

Comparison of the clinical and genetic features of amyotrophic lateral sclerosis across Cuban, Uruguayan and Irish clinic-based populations

OBJECTIVES

This study compares the clinical characteristics of patients with amyotrophic lateral sclerosis (ALS) within three clinic-based populations from Cuba, Uruguay and Ireland and determines the impact of known ALS-associated genetic variants on phenotypic manifestations within the Cuban population.

METHODS

Demographic and clinical information was collected on 115 Cuban, 220 Uruguayan and 1038 Irish patients with ALS attending national specialist clinics through 1996-2017. All Cuban patients and 676 Irish patients underwent next-generation DNA sequencing and were screened for the pathogenic C9orf72 repeat expansion.

RESULTS

The mean age of onset was younger in the Cuban (53.0 years, 95% CI 50.4 to 55.6) and Uruguayan (58.2 years, 95% CI 56.5 to 60.0) populations compared with the Irish population (61.6 years, 95% CI 60.9 to 62.4). No differences in survival between populations were observed. 1.7 % (95% CI 0.6 to 4.1) of Cubans with ALS carried the C9orf72 repeat expansion compared with 9.9% (95% CI 7.8 to 12.0) of Irish patients with ALS (p=0.004). Other known variants identified in the Cuban population included ANG (one patient), CHCHD10 (one patient) and DCTN1 (three patients).

CONCLUSIONS AND RELEVANCE

This study is the first to describe the clinical characteristics of ALS in Cuban and Uruguayan populations and report differences between the Cuban and Irish genetic signature in terms of known ALS-associated genetic variants. These novel clinical and genetic data add to our understanding of ALS across different and understudied populations.

Younger age of onset in familial amyotrophic lateral sclerosis is a result of pathogenic gene variants, rather than ascertainment bias

OBJECTIVE

Amyotrophic lateral sclerosis (ALS) is a rapidly progressive neurodegenerative disease of motor neurons with a median survival of 2 years. Familial ALS has a younger age of onset than apparently sporadic ALS. We sought to determine whether this younger age of onset is a result of ascertainment bias or has a genetic basis.

METHODS

Samples from people with ALS were sequenced for 13 ALS genes. To determine the effect of genetic variation, age of onset was compared in people with sporadic ALS carrying a pathogenic gene variant and those who do not; to determine the effect of family history, we compared those with genetic sporadic ALS and familial ALS.

RESULTS

There were 941 people with a diagnosis of ALS, 100 with familial ALS. Of 841 with apparently sporadic ALS, 95 carried a pathogenic gene variant. The mean age of onset in familial ALS was 5.3 years younger than for apparently sporadic ALS (p=6.0×10-5, 95% CI 2.8 to 7.8 years). The mean age of onset of genetic sporadic ALS was 2.9 years younger than non-genetic sporadic ALS (p=0.011, 95% CI 0.7 to 5.2 years). There was no difference between the mean age of onset in genetic sporadic ALS and familial ALS (p=0.097).

CONCLUSIONS

People with familial ALS have an age of onset about 5 years younger than those with apparently sporadic ALS, and we have shown that this is a result of Mendelian gene variants lowering the age of onset, rather than ascertainment bias.

Changing epidemiology of motor neurone disease in Scotland

OBJECTIVES

Scotland benefits from an integrated national healthcare team for motor neurone disease (MND) and a tradition of rich clinical data capture using the Scottish MND Register (launched in 1989; one of the first national registers). The Scottish register was re-launched in 2015 as Clinical Audit Research and Evaluation of MND (CARE-MND), an electronic platform for prospective, population-based research. We aimed to determine if incidence of MND is changing over time.

METHODS

Capture-recapture methods determined the incidence of MND in 2015-2016. Incidence rates for 2015-2016 and 1989-1998 were direct age and sex standardised to allow time-period comparison. Phenotypic characteristics and socioeconomic status of the cohort are described.

RESULTS

Coverage of the CARE-MND platform was 99%. Crude incidence in the 2015-2017 period was 3.83/100,000 person-years (95% CI 3.53-4.14). Direct age-standardised incidence in 2015 was 3.42/100,000 (95% CI 2.99-3.91); in 2016, it was 2.89/100,000 (95% CI 2.50-3.34). The 1989-1998 direct standardised annual incidence estimate was 2.32/100,000 (95% CI 2.26-2.37). 2015-2016 standardised incidence was 66.9% higher than Northern European estimates. Socioeconomic status was not associated with MND.

CONCLUSIONS

Our data show a changing landscape of MND in Scotland, with a rise in incidence by 36.0% over a 25-year period. This is likely attributable to ascertainment in the context of improved neurological services in Scotland. Our data suggest that CARE-MND is a reliable national resource and findings can be extrapolated to the other Northern European populations.

Transgenic and physiological mouse models give insights into different aspects of amyotrophic lateral sclerosis

A wide range of genetic mouse models is available to help researchers dissect human disease mechanisms. Each type of model has its own distinctive characteristics arising from the nature of the introduced mutation, as well as from the specific changes to the gene of interest. Here, we review the current range of mouse models with mutations in genes causative for the human neurodegenerative disease amyotrophic lateral sclerosis. We focus on the two main types of available mutants: transgenic mice and those that express mutant genes at physiological levels from gene targeting or from chemical mutagenesis. We compare the phenotypes for genes in which the two classes of model exist, to illustrate what they can teach us about different aspects of the disease, noting that informative models may not necessarily mimic the full trajectory of the human condition. Transgenic models can greatly overexpress mutant or wild-type proteins, giving us insight into protein deposition mechanisms, whereas models expressing mutant genes at physiological levels may develop slowly progressing phenotypes but illustrate early-stage disease processes. Although no mouse models fully recapitulate the human condition, almost all help researchers to understand normal and abnormal biological processes, providing that the individual characteristics of each model type, and how these may affect the interpretation of the data generated from each model, are considered and appreciated.

Clinical features and prognosis of amyotrophic lateral sclerosis in Africa: the TROPALS study

OBJECTIVE

We describe and compare the sociodemographic and clinical features, treatments, and prognoses and survival times of patients with amyotrophic lateral sclerosis (ALS) in Africa.

METHODOLOGY

We conducted a multicentre, hospital-based cohort study in Africa. Patients with ALS diagnosed in the neurology departments of participating hospitals from 2005 to 2017 were included. Subgroup analysis was performed by subcontinent. Survival analyses were conducted using the Cox proportional hazards model.

RESULTS

Nine centres from eight African countries participated. A total of 185 patients with ALS were included: 114 from Northern Africa, 41 from Western Africa and 30 from Southern Africa. A male predominance (male to female ratio 2.9) was evident. The median age at onset was 53.0 years (IQR 44.5-64.0 years). The onset was bulbar in 22.7%. Only 47 patients (26.3%) received riluzole, mainly in Northern and Western Africa. The median survival from the time of diagnosis was 14.0 months (95% CI 10.7 to 17.2 months). The median survival was longer in Northern Africa (19.0 months, 95% CI 10.8 to 27.2 months) than in Western (4.0 months, 95% CI 0.8 to 7.1 months) and Southern (11.0 months, 95% CI 5.6 to 16.4 months) Africa (Breslow test, p<0.0001). Both subcontinental location and riluzole treatment independently affected survival.

CONCLUSION

More African patients with ALS were male and younger and exhibited a lower proportion of bulbar onset compared with patients with ALS from Western nations. Survival was consistent with that in Western registers but far shorter than what would be expected for young patients with ALS. The research improves our understanding of the disease in Africa.

CSF and blood biomarkers in amyotrophic lateral sclerosis: protocol for a systematic review and meta-analysis

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a highly progressive and debilitating neurodegenerative disease, which usually leads to the death of affected individuals within a few years after the onset of symptoms. ALS is currently incurable and very little is known about its pathophysiology. Finding validated biomarkers will help us to advance our understanding of ALS etiology and find better strategies for early diagnosis and management of the disease. The main aim of the present systematic review is to evaluate the concentration of 11 frequently reported biomarkers for ALS in peripheral blood and CSF of patients diagnosed with ALS compared with controls.

METHODS

This systematic review protocol has been established according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocol (PRISMA-P) 2015 guideline. We will include all types of observational studies with human subjects that investigated the concentrations of intended biomarkers (amyloid beta (Aβ-42), tau and phosphorylated tau (p-Tau), neurofilaments, S100β, cystatin C, progranulin (PGRN), glial fibrillary acidic protein (GFAP), monocyte chemoattractant protein-1 (MCP-1), brain-derived neurotrophic factor (BDNF), TAR DNA-binding protein-43 (TDP43), YKL-40, and CHIT1 in CSF or peripheral blood of ALS patients for initial assessment. Also, we will include case series with a minimum of 10 cases and clinical trials which have measured baseline biomarker levels. Case studies, case reports, reviews, letters, and animal and in vitro studies will be excluded. Multiple electronic databases including Cochrane Library, MEDLINE (PubMed), ISI Web of Science, and EMBASE will be searched to find all eligible articles published since 1980. No language restriction will be applied. All titles and abstracts retrieved by searching information sources will be evaluated independently by two authors against the eligibility criteria. The following information will be extracted from each included study by two independent authors: bibliographic details (first author, study title, year of publication, country), demographics and clinical information (number of patients and controls, type of ALS and controls, study design, age, gender, specimen, biomarkers levels, ALS functional rating scale Revised (ALSFRS-R), duration of disease), and measurements (method, value type, biomarkers levels). We will use the extracted mean and standard deviation (SD) of biomarkers concentrations to calculate the standardized mean difference (SMD) and 95% confidence intervals (CI). The primary outcome measures are the mean difference of biomarker levels between ALS patients and controls, different types of ALS, and ALS patients with genetic mutations.

DISCUSSION

We will systematically review the literature and analyze studies of biomarker level in CSF and peripheral blood of patients with ALS and controls. The results will help us to identify biomarkers with possible diagnostic and prognostic value.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42017078127.

Global, regional, and national burden of motor neuron diseases 1990-2016: a systematic analysis for the Global Burden of Disease Study 2016

BACKGROUND

Understanding how prevalence, incidence, and mortality of motor neuron diseases change over time and by location is crucial for understanding the causes of these disorders and for health-care planning. Our aim was to produce estimates of incidence, prevalence, and disability-adjusted life-years (DALYs) for motor neuron diseases for 195 countries and territories from 1990 to 2016 as part of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2016.

METHODS

The motor neuron diseases included in this study were amyotrophic lateral sclerosis, spinal muscular atrophy, hereditary spastic paraplegia, primary lateral sclerosis, progressive muscular atrophy, and pseudobulbar palsy. Incidence, prevalence, and DALYs were estimated using a Bayesian meta-regression model. We analysed 14 165 site-years of vital registration cause of death data using the GBD 2016 cause of death ensemble model. The 84 risk factors quantified in GBD 2016 were tested for an association with incidence or death from motor neuron diseases. We also explored the relationship between Socio-demographic Index (SDI; a compound measure of income per capita, education, and fertility) and age-standardised DALYs of motor neuron diseases.

FINDINGS

In 2016, globally, 330 918 (95% uncertainty interval [UI] 299 522-367 254) individuals had a motor neuron disease. Motor neuron diseases have caused 926 090 (881 566-961 758) DALYs and 34 325 (33 051-35 364) deaths in 2016. The worldwide all-age prevalence was 4·5 (4·1-5·0) per 100 000 people, with an increase in age-standardised prevalence of 4·5% (3·4-5·7) over the study period. The all-age incidence was 0·78 (95% UI 0·71-0·86) per 100 000 person-years. No risk factor analysed in GBD showed an association with motor neuron disease incidence. The largest age-standardised prevalence was in high SDI regions: high-income North America (16·8, 95% UI 15·8-16·9), Australasia (14·7, 13·5-16·1), and western Europe (12·9, 11·7-14·1). However, the prevalence and incidence were lower than expected based on SDI in high-income Asia Pacific.

INTERPRETATION

Motor neuron diseases have low prevalence and incidence, but cause severe disability with a high fatality rate. Incidence of motor neuron diseases has geographical heterogeneity, which is not explained by any risk factors quantified in GBD, suggesting other unmeasured risk factors might have a role. Between 1990 and 2016, the burden of motor neuron diseases has increased substantially. The estimates presented here, as well as future estimates based on data from a greater number of countries, will be important in the planning of services for people with motor neuron diseases worldwide.

FUNDING

Bill & Melinda Gates Foundation.

An epidemiologic investigation of amyotrophic lateral sclerosis in Thrace, Turkey, 2006-2010

OBJECTIVE

The aim of the study was to investigate the incidence and prevalence of amyotrophic lateral sclerosis (ALS) in Thrace, Turkey in a five-year time period (2006-2010).

METHODS

Study population included residents of three provinces (Edirne, Tekirdag, Kırklareli) in the Thrace region. Cases were ascertained from all of the neurologic centers and hospitals of these provinces. Demographic and clinical information was collected for each patient. Newly diagnosed ALS patients who are fulfilling the El Escorial revised diagnostic criteria were enrolled into the study.

RESULTS

We identified a total of 145 patients (93 males, 52 females). The mean age at diagnosis was 57.0 ± 13.6. According to El Escorial criteria, 60.0% of the cases were definite ALS, 24.8% were probable, and 15.2% were possible ALS. Thirty-two cases were bulbar (22.1%), 113 cases (77.9%) were spinal onset. Mean time delay from onset to diagnosis was 12.0 ± 11.2 months. Age-gender standardized incidence rates with reference to Turkey, USA 2008 census were 1.9 (95% confidence interval (CI), 1.8-2.1), 1.9 (95%CI, 1.8-2.2) for overall. There were 112 living ALS patients at the end of the study. Crude point prevalence was calculated as 7.3 per 100,000 population (95%CI, 5.9-8.7).

CONCLUSIONS

This is the first study to provide fundamental data about demographic and clinical characteristics about ALS in Thrace region of Turkey. Incidence and prevalence of ALS in Thrace region of Turkey appear to be comparable with European countries.

Multicentre, cross-cultural, population-based, case-control study of physical activity as risk factor for amyotrophic lateral sclerosis

OBJECTIVE

To investigate the association between physical activity (PA) and amyotrophic lateral sclerosis (ALS) in population-based case-control studies in three European countries using a validated and harmonised questionnaire.

METHODS

Patients with incident ALS and controls were recruited from five population-based registers in The Netherlands, Ireland and Italy. Demographic and data regarding educational level, smoking, alcohol habits and lifetime PA levels in both leisure and work time were gathered by questionnaire, and quantified using metabolic equivalent of task scores. Logistic regression models adjusting for PA-related factors were used to determine the association between PA and ALS risk, and forest plots were used to visualise heterogeneity between regions.

RESULTS

1557 patients and 2922 controls were included. We found a linear association between ALS and PA in leisure time (OR 1.07, P=0.01) and occupational activities (OR 1.06, P<0.001), and all activities combined (OR 1.06, P<0.001), with some heterogeneity between regions: the most evident association was seen in the Irish and Italian cohorts. After adjustment for other occupational exposures or exclusion of patients with a C9orf72 mutation, the ORs remained similar.

CONCLUSION

We provide new class I evidence for a positive association between PA and risk of ALS in a large multicentre study using harmonised methodology to objectively quantify PA levels, with some suggestions for population differences.

Age-specific ALS incidence: a dose-response meta-analysis

To evaluate the association between worldwide ALS incidence rates and age, using a dose-response meta-analysis. We reviewed Medline and Embase up to July 2016 and included all population-based studies of newly-diagnosed cases, using multiple sources for case ascertainment. A dose-response meta-analysis was performed. A meta-regression investigated potential sources of heterogeneity. Of 3254 articles identified in the literature, we included 41 incidence studies covering 42 geographical areas. Overall, the fit between observed and predicted age-specific rates was very good. The expected variation of ALS incidence with age was characterized, in each study, by a progressive increase in the incidence from the 40s leading to a peak in the 60s or 70s, followed by a sharp decrease. Cochran's Q test suggested a significant heterogeneity between studies. Overall, estimated patterns of ALS age-specific incidence (at which the peak was reached) were similar among subcontinents of Europe and North America: peak of ALS incidence ranged in these areas between 6.98 and 8.17/100,000 PYFU, which referred to age in the range 71.6-77.4 years. The relationship between age and ALS incidence appeared different for Eastern Asia which was characterized by a peak of ALS incidence at 2.20/100,000 PYFU around 75 years of age. This study confirms the consistency of the age-specific ALS incidence pattern within different subcontinents. Age-specific incidence appears lower in Eastern Asia as compared to Europe and North America.

Referral bias in ALS epidemiological studies

Background

Despite concerns about the representativeness of patients from ALS tertiary centers as compared to the ALS general population, the extent of referral bias in clinical studies remains largely unknown. Using data from EURALS consortium we aimed to assess nature, extent and impact of referral bias.

Methods

Four European ALS population-based registries located in Ireland, Piedmont, Puglia, Italy, and Limousin, France, covering 50 million person-years, participated. Demographic and clinic characteristics of ALS patients diagnosed in tertiary referral centers were contrasted with the whole ALS populations enrolled in registries in the same geographical areas.

Results

Patients referred to ALS centers were younger (with difference ranging from 1.1 years to 2.4 years), less likely to present a bulbar onset, with a higher proportion of familial antecedents and a longer survival (ranging from 11% to 15%) when compared to the entire ALS population in the same geographic area.

Conclusions

A trend for referral bias is present in cohorts drawn from ALS referral centers. The magnitude of the possible referral bias in a particular tertiary center can be estimated through a comparison with ALS patients drawn from registry in the same geographic area. Studies based on clinical cohorts should be cautiously interpreted. The presence of a registry in the same area may improve the complete ascertainment in the referral center.

Variation in worldwide incidence of amyotrophic lateral sclerosis: a meta-analysis

Background

To assess the worldwide variation of amyotrophic lateral sclerosis (ALS) incidence, we performed a systematic review and meta-analysis of population-based data published to date.

Methods

We reviewed Medline and Embase up to June 2015 and included all population-based studies of newly diagnosed ALS cases, using multiple sources for case ascertainment. ALS crude and standardized incidence (on age and sex using the US 2010 population) were calculated. Random effect meta-analysis and meta-regression were performed using the subcontinent as the main study level covariate. Sources of heterogeneity related to the characteristics of the study population and the study methodology were investigated.

Results

Among 3216 records, 44 studies were selected, covering 45 geographical areas in 11 sub-continents. A total of 13 146 ALS cases and 825 million person-years of follow-up (PYFU) were co-nsidered. The overall pooled worldwide crude ALS incidence was at 1.75 (1.55–1.96)/100 000 PYFU; 1.68 (1.50–1.85)/100 000 PYFU after standardization. Heterogeneity was identified in ALS standardized incidence between North Europe [1.89 (1.46–2.32)/100 000 PYFU] and East Asia [0.83 (0.42–1.24)/100 000 PYFU, China and Japan P = 0.001] or South Asia [0.73 (0.58–0.89)/100 000/PYFU Iran, P = 0.02]. Conversely, homogeneous rates have been reported in populations from Europe, North America and New Zealand [pooled ALS standardized incidence of 1.81 (1.66-1.97)/100 000 PYFU for those areas].

Conclusion

This review confirms a heterogeneous distribution worldwide of ALS, and sets the scene to sustain a collaborative study involving a wide international consortium to investigate the link between ancestry, environment and ALS incidence.

Age-dependent sex ratios of motor neuron disease: French nationwide study and meta-analysis

OBJECTIVE

To examine the relation of age with male-to-female (M/F) ratios and incidence rates of motor neuron disease (MND) in a French nationwide study and meta-analysis of incidence studies.

METHODS

We used data from the French National Health Insurance databases. Patients with incident MND (2010-2014) were identified based on drug claims (riluzole), hospitalization records, death records, and long-term chronic disease benefits. We estimated age-specific M/F incidence ratios using Poisson regression. Poisson, Gompertz, and multistep models were used to model the relation between age and incidence. We performed a meta-analysis (n = 28 studies) and used meta-regression to examine the relation of age with incidence rates and ratios.

RESULTS

In France, we identified 10,848 patients with incident MND (6,021 men, 4,827 women). Incidence was higher in men than in women in all age groups. M/F ratios were significantly different across age groups and followed a quadratic trend (p < 0.001). Between 20 and 49 years, the average M/F ratio was 2.26 (95% confidence interval [CI] = 1.96-2.62); it was 1.41 (95% CI = 1.35-1.47) between 50 and 84 years, and 1.88 (95% CI = 1.64-2.17) after 85 years. Incidence was lower in women than men at younger ages, but increased more steeply in women than men. Similar patterns were observed in the meta-analysis of incidence studies, especially in 19 higher-quality studies.

CONCLUSION

The relation between age and M/F incidence ratios of MND follows a quadratic U-shaped pattern with an abrupt drop after the fifth decade. The change in M/F ratios before and after menopause suggests that reproductive/hormonal protective factors have a role in women and should prompt further studies to explore this hypothesis.

Association Between Decline in Slow Vital Capacity and Respiratory Insufficiency, Use of Assisted Ventilation, Tracheostomy, or Death in Patients With Amyotrophic Lateral Sclerosis

Importance

The prognostic value of slow vital capacity (SVC) in relation to respiratory function decline and disease progression in patients with amyotrophic lateral sclerosis (ALS) is not well understood.

Objective

To investigate the rate of decline in percentage predicted SVC and its association with respiratory-related clinical events and mortality in patients with ALS.

Design, Setting, and Participants

This retrospective study included 893 placebo-treated patients from 2 large clinical trials (EMPOWER and BENEFIT-ALS, conducted from March 28, 2011, to November 1, 2012, and from October 23, 2012, to March 21, 2014, respectively) and an ALS trial database (PRO-ACT, containing studies completed between 1990 and 2010) to investigate the rate of decline in SVC. Data from the EMPOWER trial (which enrolled adults with possible, probable, or definite ALS; symptom onset within 24 months before screening; and upright SVC at least 65% of predicted value for age, height, and sex) were used to assess the relationship of SVC to respiratory-related clinical events; 456 patients randomized to placebo were used in this analysis. The 2 clinical trials included patients from North America, Australia, and Europe.

Main Outcomes and Measures

Clinical events included the earlier of time to death or time to decline in the Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R) respiratory subdomain, time to onset of respiratory insufficiency, time to tracheostomy, and all-cause mortality.

Results

Among 893 placebo-treated patients with ALS, the mean (SD) patient age was 56.7 (11.2) years, and the mean (SD) SVC was 90.5% (17.1%) at baseline; 65.5% (585 of 893) were male, and 20.5% (183 of 893) had bulbar-onset ALS. In EMPOWER, average decline of SVC from baseline through 1.5-year follow-up was -2.7 percentage points per month. Steeper declines were found in patients older than 65 years (-3.6 percentage points per month [P = .005 vs <50 years and P = .007 vs 50-65 years) and in patients with an ALSFRS-R total score of 39 or less at baseline (-3.1 percentage points per month [P < .001 vs >39]). When the rate of decline of SVC was slower by 1.5 percentage points per month in the first 6 months, risk reductions for events after 6 months were 19% for decline in the ALSFRS-R respiratory subdomain or death after 6 months, 22% for first onset of respiratory insufficiency or death after 6 months, 23% for first occurrence of tracheostomy or death after 6 months, and 23% for death at any time after 6 months (P < .001 for all).

Conclusions and Relevance

The rate of decline in SVC is associated with meaningful clinical events in ALS, including respiratory failure, tracheostomy, or death, suggesting that it is an important indicator of clinical progression.

Hypermetabolism is a deleterious prognostic factor in patients with amyotrophic lateral sclerosis

BACKGROUND AND PURPOSE

The aim of this study was to investigate patients with amyotrophic lateral sclerosis in order to determine their nutritional, neurological and respiratory parameters, and survival according to metabolic level.

METHODS

Nutritional assessment included resting energy expenditure (REE) measured by indirect calorimetry [hypermetabolism if REE variation (ΔREE) > 10%] and fat mass (FM) using impedancemetry. Neurological assessment included the Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised score. Survival analysis used the Kaplan-Meier method and multivariate Cox model.

RESULTS

A total of 315 patients were analysed. Median age at diagnosis was 65.9 years and 55.2% of patients were hypermetabolic. With regard to the metabolic level (ΔREE: < 10%, 10-20% and >20%), patients with ΔREE > 20% initially had a lower FM(29.7% vs. 32.1% in those with ΔREE ≤10%; P = 0.0054). During follow-up, the median slope of Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised tended to worsen more in patients with ΔREE > 20% (-1.4 vs. -1.0 points/month in those with ΔREE ≤10%; P = 0.07). Overall median survival since diagnosis was 18.4 months. ΔREE > 20% tended to increase the risk of dying compared with ΔREE ≤10% (hazard ratio, 1.33; P = 0.055). In multivariate analysis, an increased REE:FM ratio was independently associated with death (hazard ratio, 1.005; P = 0.001).

CONCLUSIONS

Hypermetabolism is present in more than half of patients with amyotrophic lateral sclerosis. It modifies the body composition at diagnosis, and patients with hypermetabolism >20% have a worse prognosis than those without hypermetabolism.

Amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease, is characterized by the degeneration of both upper and lower motor neurons, which leads to muscle weakness and eventual paralysis. Until recently, ALS was classified primarily within the neuromuscular domain, although new imaging and neuropathological data have indicated the involvement of the non-motor neuraxis in disease pathology. In most patients, the mechanisms underlying the development of ALS are poorly understood, although a subset of patients have familial disease and harbour mutations in genes that have various roles in neuronal function. Two possible disease-modifying therapies that can slow disease progression are available for ALS, but patient management is largely mediated by symptomatic therapies, such as the use of muscle relaxants for spasticity and speech therapy for dysarthria.

The Rotterdam Study: 2018 update on objectives, design and main results

The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in The Netherlands. The study targets cardiovascular, endocrine, hepatic, neurological, ophthalmic, psychiatric, dermatological, otolaryngological, locomotor, and respiratory diseases. As of 2008, 14,926 subjects aged 45 years or over comprise the Rotterdam Study cohort. Since 2016, the cohort is being expanded by persons aged 40 years and over. The findings of the Rotterdam Study have been presented in over 1500 research articles and reports (see www.erasmus-epidemiology.nl/rotterdamstudy ). This article gives the rationale of the study and its design. It also presents a summary of the major findings and an update of the objectives and methods.

The changing picture of amyotrophic lateral sclerosis: lessons from European registers

Prospective population based-registers of amyotrophic lateral sclerosis (ALS) have operated in Europe for over two decades, and have provided important insights into our understanding of ALS. Here, we review the benefits that population registers have brought to the understanding of the incidence, prevalence, phenotype and genetics of ALS and outline the core operating principles that underlie these registers and facilitate international collaboration. Going forward, we offer lessons learned from our collective experience of operating population-based ALS registers in Europe for over two decades, focusing on register design, maintenance, identification and management of bias and the value of cross-national harmonisation and integration.

A clinical tool for predicting survival in ALS

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a progressive and usually fatal neurodegenerative disease. Survival from diagnosis varies considerably. Several prognostic factors are known, including site of onset (bulbar or limb), age at symptom onset, delay from onset to diagnosis and the use of riluzole and non-invasive ventilation (NIV). Clinicians and patients would benefit from a practical way of using these factors to provide an individualised prognosis.

METHODS

575 consecutive patients with incident ALS from a population-based registry in South-East England register for ALS (SEALS) were studied. Their survival was modelled as a two-step process: the time from diagnosis to respiratory muscle involvement, followed by the time from respiratory involvement to death. The effects of predictor variables were assessed separately for each time interval.

FINDINGS

Younger age at symptom onset, longer delay from onset to diagnosis and riluzole use were associated with slower progression to respiratory involvement, and NIV use was associated with lower mortality after respiratory involvement, each with a clinically significant effect size. Riluzole may have a greater effect in younger patients and those with longer delay to diagnosis. A patient's survival time has a roughly 50% chance of falling between half and twice the predicted median.

INTERPRETATION

A simple and clinically applicable graphical method of predicting an individual patient's survival from diagnosis is presented. The model should be validated in an independent cohort, and extended to include other important prognostic factors.

Hospitalizations due to respiratory failure in patients with Amyotrophic Lateral Sclerosis and their impact on survival: a population-based cohort study

Background

Respiratory failure, infections and aspiration pneumonia, are the main causes of morbidity and mortality in Amyotrophic Lateral Sclerosis (ALS). In a population-based cohort, we assessed (a) hospital utilization and (b) impact of hospitalization for respiratory failure on survival.

Methods

All patients with incident ALS in Friuli Venezia Giulia region, Italy, from 2002 to 2009, were identified through multiple sources. Diagnosis was validated through clinical documentation review. For each patient, we extracted the records of all hospitalizations after ALS diagnosis from the regional hospitalization database. Cox proportional hazards model survival Hazard Ratio (HR), with 95 % Confidence Interval (95 % CI), was calculated.

Results

Out of 262 patients, 98.1 % had at least 1 and 58.0 % ≥3 hospitalizations. Emergency admissions occurred in 77.5 % of patients and a diagnosis of respiratory failure in 55.0 %. Patients underwent a total of 885 hospitalizations. The leading diagnosis was respiratory failure (31.6 % of hospitalizations). This diagnosis occurred most frequently in emergency (45.6 %) than in elective admissions (26.4 %). The second leading diagnosis was pneumonia (14.2 %), 24.9 and 6.3 % respectively. The leading procedure was mechanical ventilation (18.4 %), performed in 29.9 % of emergency and in 12.4 % of elective admissions. After adjustment for site of onset, age and diagnostic delay, a first hospitalization for respiratory failure had a strong adverse effect on survival (HR 4.00; 95 % CI 3.00; 5.34).

Conclusions

Respiratory failure, pneumonia and aspiration pneumonia were major determinants of hospitalizations and emergency admissions and often dealt with in emergency admissions. A first hospitalization for respiratory failure had a strong adverse effect on survival. Strategies to improve home management of respiratory conditions in patients with ALS and to optimize hospital care utilization are needed.

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-016-0297-y) contains supplementary material, which is available to authorized users.

Projected increase in amyotrophic lateral sclerosis from 2015 to 2040

Although amyotrophic lateral sclerosis (ALS) is relatively rare, the socioeconomic significance of the disease is extensive. It is therefore vital to project the epidemiologic trend of ALS. To date, there have been few published studies attempting to estimate the number and distribution of ALS cases in the upcoming years. Here we show that the number of ALS cases across the globe will increase from 222,801 in 2015 to 376,674 in 2040, representing an increase of 69%. This increase is predominantly due to ageing of the population, particularly among developing nations. This projection is likely an underestimate due to improving healthcare and economic conditions. The results should be used to inform healthcare policy to more efficiently allocate healthcare resources.

The socioeconomic burden of amyotrophic lateral sclerosis (ALS) is high, but the projected number of cases in the upcoming years is unclear. Here, the authors estimate the number and distribution of ALS cases to 2040, and show that cases are projected to increase, particularly in developing nations.

Amyotrophic lateral sclerosis and motor neuron syndromes in Asia

While the past 2 decades have witnessed an increasing understanding of amyotrophic lateral sclerosis (ALS) arising from East Asia, particularly Japan, South Korea, Taiwan and China, knowledge of ALS throughout the whole of Asia remains limited. Asia represents >50% of the world population, making it host to the largest patient cohort of ALS. Furthermore, Asia represents a diverse population in terms of ethnic, social and cultural backgrounds. In this review, an overview is presented that covers what is currently known of ALS in Asia from basic epidemiology and genetic influences, through to disease characteristics including atypical phenotypes which manifest a predilection for Asians. With the recent establishment of the Pan-Asian Consortium for Treatment and Research in ALS to facilitate collaborations between clinicians and researchers across the region, it is anticipated that Asia and the Pacific will contribute to unravelling the uncertainties in ALS.

Gly482Ser PGC-1α Gene Polymorphism and Exercise-Related Oxidative Stress in Amyotrophic Lateral Sclerosis Patients

The role of exercise in Amyotrophic lateral sclerosis (ALS) pathogenesis is controversial and unclear. Exercise induces a pleiotropic adaptive response in skeletal muscle, largely through the peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), a transcriptional coactivator that regulates mitochondrial biogenesis and antioxidant defense mechanisms. It has been suggested that a Gly482Ser substitution in PGC-1α has functional relevance in human disorders and in athletic performance. To test this hypothesis, we examined the genotype distribution of PGC-1α Gly482Ser (1444 G > A) in ALS patients to evaluate whether or not the minor serine-encoding allele 482Ser is involved in oxidative stress responses during physical exercise. We genotyped 197 sporadic ALS patients and 197 healthy controls in order to detect differences in allelic frequencies and genotype distribution between the two groups. A total of 74 ALS patients and 65 controls were then comparatively assessed for plasmatic levels of the oxidative stress biomarkers, advanced oxidation protein products, ferric reducing ability and thiol groups. In addition a subgroup of 35 ALS patients were also assessed for total SOD and catalase plasmatic activity. Finally in 28 ALS patients we evaluated the plasmatic curve of the oxidative stress biomarkers and lactate during an incremental exercise test. No significant differences were observed in the genotype distribution and allelic frequency in ALS patients compared to the controls. We found significant increased advanced oxidation protein products (p < 0.001) and significant decreased ferric reducing ability (p < 0.001) and thiol groups (p < 0.001) in ALS patients compared to controls. When comparing different genotypes of PGC-1α, no relation between Gly482Ser polymorphism and oxidative stress biomarker levels was detected in resting conditions. On the other hand, when considering exercise performance, lactate levels were significantly higher (between p < 0.01 and p < 0.001) and greater protein oxidative products were found in AA (Ser482Ser) compared to GG (Gly482Gly) and GA (Gly482Ser) ALS patients. Our findings highlight the importance and confirm the involvement of oxidative stress in ALS pathogenesis. Although not associated with 1444 G > A SNP, ALS patients with Gly482Ser allelic variant show increased exercise-related oxidative stress. This thus highlights the possible role of this antioxidant defense transcriptional coactivator in ALS.

Stratification of ALS patients' survival: a population-based study

The natural history of amyotrophic lateral sclerosis (ALS) and patient risk stratification are areas of considerable research interest. We aimed (1) to describe the survival of a representative cohort of French ALS patients, and (2) to identify covariates associated with various patterns of survival using a risk classification analysis. ALS patients recruited in the FRALim register (2000-2013) were included. Time-to-death analyses were performed using Kaplan-Meier method and Cox model. A recursive partitioning and amalgamation (RECPAM) algorithm analysis identified subgroups of patients with different patterns of survival. Among 322 patients, median survival times were 26.2 and 15.6 months from time of onset and of diagnosis, respectively. Four groups of patients were identified, depending on their baseline characteristics and survival (1) ALSFRS-R slope >0.46/month and definite or probable ALS (median survival time (MST) 10.6 months); (2) ALSFRS-R slope >0.46/month and possible or probable laboratory-supported ALS (MST: 18.1 months); (3) ALSFRS-R slope ≤0.46/month and definite or probable ALS (MST: 22.5 months), and (4) ALSFRS-R slope ≤0.46/month and possible or probable laboratory-supported ALS (MST: 37.6 months). Median survival time is among the shortest ever reported by a worldwide population-based study. This is probably related to the age structure of the patients (the oldest identified to date), driven by the underlying population (30 % of subjects older than 60 years). Further research in the field of risk stratification could help physicians better anticipate prognosis of ALS patients, and help improve the design of randomized controlled trials.