Multiple sclerosis mortality and patterns of comorbidity in the United States from 1990 to 2001

Multiple Sclerosis in Black and Hispanic Populations: Serving the Underserved

Multiple sclerosis has historically been characterized as a disease that affects young women of European ancestry, but recent studies indicate that the incidence and prevalence of the disease is much higher in Black and Hispanic populations than previously recognized. There is evidence that there is a more severe disease course in these populations. , but the intersection of genetic underpinnings and social determinants of health (SDOH) is poorly understood due to the lack of diversity in clinical research. Improving health disparities will involve multiple stakeholders in efforts to improve SDOH and raise awareness about research involvement and the importance of developing personalized health care plans to combat this disease.

Association of multiple-sclerosis-related mortality with COVID-19 and other common infections: a multiple causes of death analysis

BACKGROUND AND PURPOSE

People with multiple sclerosis (MS) suffer from higher infection-related mortality compared to the general population; however, sparse data are available on the increased risk of death associated with coronavirus disease 2019 (COVID-19) and other common types of infections.

METHODS

All mortality records and multiple-cause-of-death data in 2010-2021 of residents in the Veneto region (northeastern Italy) were extracted. Mention of specific infections was compared between death certificates reporting MS or not. Odds ratios (OR) with 95% confidence intervals (95% CI) were estimated by conditional logistic regression matching by age, sex and calendar year. The bimonthly averages of MS-related deaths in 2010-2019 were compared with those registered during the pandemic (2020-2021).

RESULTS

Of 580,015 deaths through 2010-2021, MS was mentioned in 850 cases (0.15%), 59.3% women. Influenza and pneumonia were reported in 18.4% of MS-related compared to 11.0% non-MS-related deaths (OR 2.72, 95% CI 2.28-3.25). The odds of mention of urinary tract infections was significantly greater in MS-related deaths of men (OR 8.16, 95% CI 5.23-12.7) than women (OR 3.03, 95% CI 1.82-5.02). Aspiration pneumonia, pressure ulcers/skin infections and sepsis were also significantly associated with MS-related deaths. Reporting of COVID-19 as a cause of death did not significantly differ between deaths with and without mention of MS (approximately 11% of both). However, compared to 2010-2019, peaks in MS-related deaths were observed during the pandemic waves.

CONCLUSIONS

Infections continue to play a significant role in MS-related deaths, underlying the need to improve prevention and management strategies.

Understanding and managing autonomic dysfunction in persons with multiple sclerosis

INTRODUCTION

Multiple sclerosis (MS) is a chronic demyelinating immune mediated disease of the central nervous system. Autonomic dysfunction (AD) is frequently present in persons with MS (pwMS) and increases with disease duration and progression.

AREAS COVERED

Cardiovascular, genitourinary, and sudomotor autonomic dysfunction in pwMS are reviewed and managing of these disorders is addressed.

EXPERT OPINION

AD in pwMS can manifest with a myriad of symptoms including cardiovascular, urogenital, and sweating disorders. These symptoms can significantly impact the quality of life of pwMS with poor tolerance of upright position, difficulties in sexual function, and low endurance of physical activity especially in warm environments. Health professionals involved in care of pwMS should possess basic knowledge of the function of the autonomic nervous system and be informed of the way disorders of the autonomic function may manifest in pwMS in order to provide the proper care.

Influence of Comorbidities on Healthcare Expenditures and Perceived Physical and Mental Health Status Among Adults with Multiple Sclerosis: A Propensity Score-Matched US National-Level Study

Objective

To evaluate the effect of comorbidities on healthcare expenditures and perceived physical and mental health status among adults with multiple sclerosis (MS) compared to propensity score-matched non-MS controls.

Methods

A retrospective, cross-sectional, matched cohort study was conducted using Medical Expenditure Panel Survey (2005–2015) data. The base study sample consisted of adults (age ≥18 years) who were alive and had positive total healthcare expenditures during the survey calendar year. Adults with MS were propensity-matched (1:1) to non-MS controls based on age, gender, and race/ethnicity using greedy matching algorithm. Healthcare expenditures consisted of total and subtypes of expenditures. Health status consisted of perceived physical and mental health status. Comorbidities were identified using ICD-9-CM and Clinical Classification System codes. Ordinary least squares regression and multinomial logistic regression were used to analyze the healthcare expenditures and health status variables, respectively.

Results

Final study sample consisted of 541 adults in each MS and non-MS control groups after propensity score matching. After adjusting for potential confounders, individuals with MS had greater total and subtypes of expenditures compared to non-MS controls, and several comorbidities (eg, depression, hypertension) were significantly associated with increased healthcare expenditures. Yearly average total expenditures (expressed in 2018 US$) were significantly (p<0.001) higher for adults with MS ($29,396) than propensity score-matched non-MS adults ($7875). Moreover, after adjusting for all individual-level factors, adults with MS experienced 363% (p<0.001) higher total expenditures compared to propensity score-matched non-MS controls. Individuals with MS were more likely to report poorer physical and good mental health status compared to propensity score-matched non-MS controls, and several comorbidities (eg, anxiety, depression) were significant independent predictors of poorer health status. For example, adults with MS were four times more likely (OR: 4.10, 95% CI: 2.42–6.96) to report fair/poor physical health status compared to excellent/very good physical health status compared with non-MS controls. Adults with MS were 42% (OR: 1.42, 95% CI: 1.01–1.99) more likely than propensity score-matched non-MS controls to report good rather than very good or excellent mental health status. However, there was no difference between adults with MS and propensity score-matched non-MS controls in terms of reporting fair or poor than very good or excellent mental health status.

Conclusion

Findings from this study indicate substantial economic and health status burdens among adults with MS at the US national-level that are significantly influenced by comorbidities.

Race and ethnicity on MS presentation and disease course

Multiple sclerosis (MS) has a strong racial and ethnic component and disproportionately affects whites of European background. Recent incidence reports suggest an increasing rate of MS among African Americans compared with whites. Despite this recent increase in MS in African Americans, Hispanics and Asians are significantly less likely to develop MS than whites of European ancestry. MS-specific mortality trends demonstrate distinctive disparities by race/ethnicity and age, suggesting that there is an unequal burden of disease. Inequalities in health along with differences in clinical characteristics that may be genetic, environmental, and social in origin may be contributing to disease variability and be suggestive of endophenotypes. The overarching goal of this review was to summarize the current understanding on the variability of disease that we observe in selected racial and ethnic populations: Hispanics and African Americans. Future challenges will be to unravel the genetic, environmental, and social determinants of the observed racial/ethnic disparities.

Multiple cause of death analysis in multiple sclerosis: A population-based study

OBJECTIVE

To gain a better understanding of the complex patterns of causes that contribute to death due to multiple sclerosis (MS) by assessing the relationship between MS and other causes of death listed on death certificates.

METHODS

Multiple cause of death data for all adult deaths (aged ≥18 years) in British Columbia, Canada, between 1986 and 2013 were accessed. All causes, as listed on the death certificate, whether underlying or contributing, were considered "any mention" causes. The associations between mention of MS on the death certificate and mention of other causes of death were examined by logistic regression, adjusted for age, sex, and calendar year (Bonferroni-corrected α level = 0.002). Findings were also sex-stratified.

RESULTS

Among 771,288 deaths, MS was mentioned on 2,153 certificates. If MS was mentioned (versus not mentioned), there was a greater chance that specific conditions contributed to the death: respiratory infection (adjusted odds ratio [aOR], 3.03 [95% confidence interval (CI), 2.73-3.36]), aspiration pneumonia (aOR, 7.15 [95% CI, 6.23-8.22]), urinary tract infection (UTI) (aOR, 10.2 [95% CI, 8.7-12.0]), other infection including sepsis (aOR, 1.34 [95% CI, 1.15-1.56]), and skin disease (aOR, 5.06 [95% CI, 3.96-6.46]). Sex differences existed for urinary tract infection (men: aOR, 14.9 [95% CI, 11.5-19.3]; women: aOR, 8.00 [95% CI, 6.53-9.81]) and chronic respiratory disease (men = aOR, 1.36 [95% CI, 1.14-1.63]; women = aOR, 0.97 [95% CI, 0.84-1.13]).

CONCLUSIONS

Deaths attributed to MS were commonly caused by infection (especially respiratory and urinary tract-related); conditions associated with advanced disability and immobility, such as aspiration pneumonia; and chronic respiratory disease in men. All are potentially modifiable; interventions that reduce the frequency or severity of these complications could improve survival in MS.

Estriol Reduces Pulmonary Immune Cell Recruitment and Inflammation to Protect Female Mice From Severe Influenza

Estriol (E3) is an endogenous estrogen in females with broad biological activity within diverse tissue types. In the context of certain T-cell-mediated autoimmune inflammatory diseases, E3 can ameliorate disease severity through immunomodulatory mechanisms that decrease tissue inflammation. Severe disease caused by influenza A virus (IAV) infection is also characterized by aberrant inflammation and immunopathology. How E3 might affect the pathogenesis of IAV infection, however, has not been explored. Gonadally intact female C57BL/6 mice that were treated with exogenous E3 during infection with mouse-adapted 2009 H1N1 had reduced total pulmonary inflammation and improved disease outcomes compared with females that received no hormone. Furthermore, compared with no hormone treatment, E3 treatment reduced the induction of genes associated with proinflammatory cytokine and chemokine responses in the lungs, which preceded clinical disease, reductions in innate immune cell recruitment, altered pulmonary T-cell skewing, and reduced antibody titers during IAV infection. Although E3 treatment was associated with reduced local and systemic anti-influenza adaptive immune responses, there was no effect of E3 on viral replication or clearance. Together, these data suggest that exogenous E3 confers protection during IAV infection through immunomodulatory mechanisms and that E3 may have broad therapeutic potential in the context of both infectious and noninfectious inflammatory diseases.

Comorbidity in US patients with multiple sclerosis

Objective

To assess the trends in the prevalence of comorbidities in US patients with multiple sclerosis (MS), and the association of demographic characteristics with the presence of comorbidities.

Study design

A retrospective analysis was conducted from a sample of 5 million patients from the IMS Health Real World Data Adjudicated Claims – US database.

Methods

Comorbidity in patients with MS was assessed by year (2006–2014), and logistic regression models evaluated the association of age, sex, and region with select comorbidities.

Results

The most common comorbidities from 2006 to 2014 were hyperlipidemia and hypertension (25.9%–29.7% of patients within an individual year), followed by gastrointestinal disease (18.4%–21.2% of patients) and thyroid disease (12.9%–17.1% of patients). The proportion with a claim for hyperlipidemia increased from 2006 to 2009, was stable from 2009 to 2011, and then declined from 2011 to 2014. The proportion with a claim for hypertension generally increased from 2006 to 2013, then declined from 2013 to 2014. The proportion with a claim for gastrointestinal disease, thyroid disease, and anxiety generally increased from 2006 to 2014. Claims for comorbidities were statistically significantly more likely among older age groups (p<0.05), with the exception of anxiety and alcohol abuse, which were statistically significantly less likely among older age groups. Claims for gastrointestinal disease (OR=0.75), thyroid disease (OR=0.36), chronic lung disease (OR=0.76), arthritis (OR=0.71), anxiety (OR=0.63), and depression (OR=0.69) were statistically significantly less likely among males versus females (all p<0.05). Claims for hyperlipidemia (OR=1.39), hypertension (OR=1.25), diabetes (OR=1.31), and alcohol abuse (OR=2.41) were significantly more likely among males (p<0.05). Many comorbidity claims were statistically significantly more likely in the Northeast and South compared with the Midwest and West.

Conclusion

This study provides select comorbidity claims estimates in US patients with MS, and thus highlights the importance of comprehensive patient care approaches.

Predictors of Mortality in Veterans with Multiple Sclerosis in an Outpatient Clinic Setting

BACKGROUND

Examining factors that increase risk of death in veterans with multiple sclerosis (MS) may help reduce MS-related mortality. We sought to determine predictors of mortality in veterans with MS attending an outpatient clinic.

METHODS

Review of electronic medical records of 226 veterans with MS regularly followed up from January 1, 2000, through December 31, 2014.

RESULTS

Mortality at the end of the 15-year study period was 14%. Patients with MS died prematurely, with a standardized mortality rate of 1.35 relative to the general (Oklahoma) population. The main causes of death documented were MS disease itself (57% of cases), infection (43%), and cancer and respiratory failure (18% each). Cox regression analysis using the whole cohort showed that progressive MS type; older age at entry into the study; presence of sensory, cerebellar, or motor (weakness and/or ataxia) concerns on presentation; more disability on presentation; higher body-mass index; being diabetic; never received disease-modifying therapy; and presence of pressure ulcers or neurogenic bladder were significant predictors of higher mortality.

CONCLUSIONS

Initial presentation by MS type (progressive MS), higher level of disability, and associated motor, sensory, and cerebellar concerns are significant predictors of MS-related mortality. The main causes of death were MS disease itself, infection, respiratory disease, and cancer. More attention should be given to preventive strategies that delay mortality, such as yearly immunization and aggressively treating MS-related complications and diabetes mellitus.

MS in self-identified Hispanic/Latino individuals living in the US

Self-identified Hispanic/Latino individuals living with multiple sclerosis (MS) in the continental United States (US) are a diverse group that represents different cultural and ancestral backgrounds. A marked variability in the way MS affects various subgroups of Hispanics in the US has been observed. We reviewed and synthesized available data about MS in Hispanics in the US. There are likely a host of multifactorial elements contributing to these observations that could be explained by genetic, environmental, and social underpinnings. Barriers to adequate MS care in Hispanics are likely to include delivery of culturally competent care and social and economic disadvantages. Considerable efforts, including the formation of a national consortium known as the Alliance for Research in Hispanic Multiple Sclerosis (ARHMS), are underway to help further explore these various factors.

Immune Response to Seasonal Influenza Vaccine in Patients with Relapsing-Remitting Multiple Sclerosis Receiving Long-term Daclizumab Beta: A Prospective, Open-Label, Single-Arm Study

BACKGROUND

For patients with relapsing-remitting multiple sclerosis (RRMS) undergoing continuous immunomodulatory therapy, understanding whether vaccinations can be performed safely and effectively is important. We tested the immune response to inactivated seasonal influenza vaccine during long-term daclizumab beta treatment.

METHODS

In this prospective, open-label, single-arm extension SELECTED study, an optional vaccine substudy was performed on patients with RRMS who had already received daclizumab beta for 1 to 2 years in previous studies. Patients were administered the seasonal vaccine as a single intramuscular dose containing three inactivated influenza virus strains: A/California/7/2009 (A/H1N1), A/Texas/50/2012 (A/H3N2), and B/Massachusetts/2/2012 (B). Endpoints included proportion of patients achieving seroprotection, proportion of patients who seroconverted, geometric mean titer ratio before and after vaccination, and adverse events reported during 28-day follow-up.

RESULTS

Ninety patients received the influenza vaccine (mean previous daclizumab beta exposure, 49.6 doses). Seroprotection (anti-hemagglutination immunoglobulin G titer ≥40) was detected in 92% (95% confidence interval [CI], 85%-97%) of patients for A/H1N1, 91% (83%-96%) for A/H3N2, and 67% (56%-76%) for B. The proportion of patients who seroconverted was 69% (95% CI, 58%-78%) for A/H1N1, 69% (58%-78%) for A/H3N2, and 44% (34%-55%) for B. The anti-hemagglutination immunoglobulin geometric mean titer ratio was 7.7 for A/H1N1, 9.0 for A/H3N2, and 4.3 for B. There were no significant adverse events considered related to vaccination during 28-day follow-up.

CONCLUSIONS

Patients with RRMS receiving long-term daclizumab beta treatment mounted an immune response to the seasonal influenza vaccine at levels considered to confer protection. No major or new safety issues were identified.

Multiple sclerosis and suicide

Mortality rates are elevated in people with multiple sclerosis (MS) relative to the general population. There is, however, some uncertainty whether suicide contributes to this. Epidemiological data suggest that the standardized mortality ratio (SMR) for suicide in MS is approximately twice that of the general population with younger males in the first few years following diagnosis most at risk. Rates of suicidal intent, a potential harbinger of more self-destructive behavior, are also elevated, but the frequency with which intent is followed by suicide is not known. Depression, severity of depression, social isolation, and alcohol abuse are associated with thoughts of suicide. The variables linked with suicide and suicidal intent are therefore well defined and should be readily available from routine clinical inquiry. While vigilance on the part of clinicians is required, particularly in the context of high-risk patients, it is also recognized that prevention is dependent on full disclosure of intent.

An excessive risk of suicide may no longer be a reality for multiple sclerosis patients

BACKGROUND

Few recent studies have shown that there is no longer an increased risk of suicide in patients affected with multiple sclerosis (MS).

OBJECTIVES

To describe suicide cases within a large French MS cohort and assess whether MS patients are at a higher risk of suicide compared with the general population.

METHODS

Data derives from a study on long-term mortality of 27,603 prevalent cases from 15 MS specialist centres. Of 1,569 deceased MS patients (5.7%) on 1 January 2010, 47 were suicides.

RESULTS

The mean time between MS clinical onset and death was 13.5 years (standard deviation (SD): 9.3 years; none within the first 3 years) and was significantly shorter than for MS patients who had died from other causes (mean = 21.4 (SD = 11.6), p < 0.0001). Age at death was also lower (46.3 vs 56.7). The standardized mortality rates were around 1 in several sensitivity analyses, reflecting no excess mortality in MS compared with general population.

CONCLUSION

Our findings indicate that an excess suicide risk may no longer be true for MS patients and highlight the changing profile of cases, occurring later in the disease course. Further studies in population-based registries are needed to confirm and explain these potential changes (e.g. treatments' impact?).

Temperature dependence of multiple sclerosis mortality rates in the United States

Background:

It is well known that multiple sclerosis (MS) patients are very sensitive to heat events. However, how MS patients respond to the significant temperature difference between the high- and low-latitude regions is not understood.

Objective:

The goal is to identify the primary factor responsible for the fact that MS mortality rates of the United States is more than three times higher in the northern states than in the southern states.

Methods:

Correlation coefficients between the age-adjusted mortality rate of MS as the underlying cause of death and the state average temperature, altitude, latitude, duration of sunshine hours, and solar radiation in the 48 contiguous states were compared.

Results:

MS mortality rates correlate significantly and inversely with temperatures in the 48 states (correlation coefficient r = −0.812 and significance p = 0.00). Durations of sunshine hours and solar radiation do not correlate significantly with MS mortality rates ( r = −0.245, −0.14, and p = 0.101, 0.342, respectively).

Conclusion:

High environmental temperature is the primary reason for the low MS mortality rates and likely the low MS prevalence in low-latitude regions. Implication of the study result is that benefits of long-term heat acclimation through gradual and prolonged exposure to environmental heat for MS patients may be greatly underappreciated.

CNS-targeted autoimmunity leads to increased influenza mortality in mice

The discovery that central nervous system (CNS)-targeted autoreactive T cells required a process of licensing in the lung revealed an unexpected relationship between these organs. The clinical and immunological significance of this finding is bidirectional in that it showed not only a mechanism by which T cells become pathogenic before entering the CNS, but also the potential for this process to influence lung immunity as well. Epidemiological studies have shown that people with multiple sclerosis (MS) suffer from increased morbidity and mortality from infectious diseases, independent of immunosuppressive therapies. Respiratory infections account for a large percentage of deaths of people with MS. In this study, to investigate the mechanisms responsible for this enhanced susceptibility, we established a comorbid model system in which mice with experimental autoimmune encephalomyelitis (EAE) were administered a sublethal dose of influenza. Whereas mice with either EAE alone or influenza alone survived, 70% of comorbid mice died as a result of uncontrolled viral replication. Immunological analyses revealed that the induction of EAE led to a surprising alteration of the lung milieu, converting an effective stimulatory influenza-reactive environment into a suppressive one. These results provide mechanistic information that may help to explain the unexpected immunological interactions.

Analysis of Diagnoses Associated with Multiple Sclerosis-Related In-Hospital Mortality Using the Premier Hospital Database

BACKGROUND

We sought to compare mortality rates and related diagnoses in hospitalized patients with multiple sclerosis (MS), those with diabetes mellitus (DM), and the general hospitalized population (GHP).

METHODS

Patients who died between 2007 and 2011 were identified in the US hospital-based Premier Healthcare Database. Demographic information was collected, mortality rates calculated, and principal diagnoses categorized.

RESULTS

Of 55,152 unique patients with MS identified, 1518 died. Mean age at death was 10 years younger for the MS group (63.4 years) than for the DM (73.3 years) and GHP (73.1 years) groups. Age-adjusted mortality rates, based on the 2000 US Standard Million Population, were 1077, 1248, and 1133 per 100,000, respectively. Infection was the most common principal diagnosis at the hospital stay during which the patient died in the MS cohort (43.1% vs. 26.3% and 24.0% in the DM and GHP groups, respectively). Other common principal diagnoses in the MS group included pulmonary (17.5%) and cardiovascular (12.1%) disease. Septicemia/sepsis/septic shock was a secondary diagnosis for 50.7% of patients with MS versus 36.0% and 31.0% of patients in the DM and GHP cohorts, respectively.

CONCLUSIONS

Patients with MS had a shorter life span than patients with DM or the GHP and were more likely to have a principal diagnosis of infection at their final hospital stay. However, the database was limited to codes recorded in the hospital; diagnoses received outside the hospital were not captured.

A home-based comprehensive care model in patients with Multiple Sclerosis: A study pre-protocol

Background Disability is prevalent in individuals with multiple sclerosis (MS), leading to difficulty in care access, significant caregiver burden, immense challenges in self-care and great societal burden.  Without highly coordinated, competent and accessible care, individuals living with progressive MS experience psychological distress, poor quality of life, suffer from life-threatening complications, and have frequent but avoidable healthcare utilizations. Unfortunately, current healthcare delivery models present severe limitations in providing easily accessible, patient-centered, coordinated comprehensive care to those with progressive MS. We propose a home-based comprehensive care model (MAHA) to address the unmet needs, challenges, and avoidable complications in individuals with progressive MS with disabling disease.

Objective The article aims to describe the study design and methods used to implement and evaluate the proposed intervention.  

Method The study will use a randomized controlled design to evaluate the feasibility of providing a 24-month, home-based, patient-centered comprehensive care program to improve quality of life, reduce complications and healthcare utilizations overtime (quarterly) for 24 months. A transdisciplinary team led by a MS-Comprehensivist will carry out this project. Fifty MS patients will be randomly assigned to the intervention and usual care program using block randomization procedures. We hypothesize that patients in the intervention group will have fewer complications, higher quality of life, greater satisfaction with care, and reduced healthcare utilization. The proposed project is also expected to be financially sustainable in fee-for-service models but best suited for and gain financial success in valued-based care systems.  

Discussion This is the first study to examine the feasibility and effectiveness of a home-based comprehensive care management program in MS patients living with progressive disability. If successful, it will have far-reaching implications in research, education and practice in terms of providing high quality but affordable care to population living with severe complex, disabling conditions.

Multiple Sclerosis Mortality Rates in Canada, 1975-2009

Background: This study examined mortality due to multiple sclerosis (MS) in Canada, 1975-2009 to determine whether there has been a change in age at death relative to the general population and decrease in MS mortality rates. Methods: Mortality rates/100,000 population for MS and all causes were calculated using data derived from Statistics Canada, age-standardized to the 2006 population. Results: The average annual Canadian MS mortality rate, 1975-2009 was 1.23/100,000. Five-year rates for 1975-79, 1980-84, 1985-89, 1990-94, 1995-99, 2000-04, 2005-09 were: 1.16, 0.94, 1.01, 1.16, 1.30, 1.43, 1.33. Trend analysis showed mortality rates over the entire 35 years were stable (average annual percent change of less than one percent). The average annual 1975-2009 rates for females and males were 1.45 and 0.99. Five-year female rates were always higher than males. Regardless of gender, there was a decrease in MS mortality rates in the 0-39 age group and increases in the 60-69, 70-79, and 80+ groups over time. In contrast, there were decreases in all-cause mortality rates across each age group. The highest MS mortality rates for 1975-2009 were consistently in the 50-59 and 60-69 groups for both genders, while the highest all-cause mortality rates were in the 80+ group. Conclusions: Changes in the age distribution of MS mortality rates indicate a shift to later age at death, possibly due to improved health care. However MS patients remain disadvantaged relative to the general population and changes in age at death are not reflected in decreased mortality rates.

Effect of comorbidity on mortality in multiple sclerosis

Objective:

We aimed to compare survival in the multiple sclerosis (MS) population with a matched cohort from the general population, and to evaluate the association of comorbidity with survival in both populations.

Methods:

Using population-based administrative data, we identified 5,797 persons with MS and 28,807 controls matched on sex, year of birth, and region. We estimated annual mortality rates. Using Cox proportional hazards regression, we evaluated the association between comorbidity status and mortality, stratifying by birth cohort, and adjusting for sex, socioeconomic status, and region. We compared causes of death between populations.

Results:

Median survival from birth in the MS population was 75.9 years vs 83.4 years in the matched population. MS was associated with a 2-fold increased risk of death (adjusted hazard ratio 2.40; 95% confidence interval: 2.24–2.58). Several comorbidities were associated with increased hazard of death in both populations, including diabetes, ischemic heart disease, depression, anxiety, and chronic lung disease. The magnitude of the associations of mortality with chronic lung disease, diabetes, hypertension, and ischemic heart disease was lower in the MS population than the matched population. The most common causes of death in the MS population were diseases of the nervous system and diseases of the circulatory system. Mortality rates due to infectious diseases and diseases of the respiratory system were higher in the MS population.

Conclusion:

In the MS population, survival remained shorter than expected. Within the MS population, comorbidity was associated with increased mortality risk. However, comorbidity did not preferentially increase mortality risk in the MS population as compared with controls.

Cost effectiveness of fingolimod, teriflunomide, dimethyl fumarate and intramuscular interferon-β1a in relapsing-remitting multiple sclerosis

OBJECTIVE

The aim of the study was to compare the cost effectiveness of fingolimod, teriflunomide, dimethyl fumarate, and intramuscular (IM) interferon (IFN)-β(1a) as first-line therapies in the treatment of patients with relapsing-remitting multiple sclerosis (RRMS).

METHODS

A Markov model was developed to evaluate the cost effectiveness of disease-modifying drugs (DMDs) from a US societal perspective. The time horizon in the base case was 5 years. The primary outcome was incremental net monetary benefit (INMB), and the secondary outcome was incremental cost-effectiveness ratio (ICER). The base case INMB willingness-to-pay (WTP) threshold was assumed to be US$150,000 per quality-adjusted life year (QALY), and the costs were in 2012 US dollars. One-way sensitivity analyses and probabilistic sensitivity analysis were conducted to test the robustness of the model results.

RESULTS

Dimethyl fumarate dominated all other therapies over the range of WTPs, from US$0 to US$180,000. Compared with IM IFN-β(1a), at a WTP of US$150,000, INMBs were estimated at US$36,567, US$49,780, and US$80,611 for fingolimod, teriflunomide, and dimethyl fumarate, respectively. The ICER of fingolimod versus teriflunomide was US$3,201,672. One-way sensitivity analyses demonstrated the model results were sensitive to the acquisition costs of DMDs and the time horizon, but in most scenarios, cost-effectiveness rankings remained stable. Probabilistic sensitivity analysis showed that for more than 90% of the simulations, dimethyl fumarate was the optimal therapy across all WTP values.

CONCLUSION

The three oral therapies were favored in the cost-effectiveness analysis. Of the four DMDs, dimethyl fumarate was a dominant therapy to manage RRMS. Apart from dimethyl fumarate, teriflunomide was the most cost-effective therapy compared with IM IFN-β(1a), with an ICER of US$7,115.

No human protein is exempt from bacterial motifs, not even one

The hypothesis that mimicry between a self and a microbial peptide antigen is strictly related to autoimmune pathology remains a debated concept in autoimmunity research. Clear evidence for a causal link between molecular mimicry and autoimmunity is still lacking. In recent studies we have demonstrated that viruses and bacteria share amino acid sequences with the human proteome at such a high extent that the molecular mimicry hypothesis becomes questionable as a causal factor in autoimmunity. Expanding upon our analysis, here we detail the bacterial peptide overlapping to the human proteome at the penta-, hexa-, hepta- and octapeptide levels by exact peptide matching analysis and demonstrate that there does not exist a single human protein that does not harbor a bacterial pentapeptide or hexapeptide motif. This finding suggests that molecular mimicry between a self and a microbial peptide antigen cannot be assumed as a basis for autoimmune pathologies. Moreover, the data are discussed in relation to the microbial immune escape phenomenon and the possible vaccine-related autoimmune effects.

Autonomic dysfunction in multiple sclerosis

Multiple sclerosis (MS) is the leading cause of neurological disability in young adults. Since the pathophysiology of MS is characterized by dissemination in space, as well as in time, the autonomic nervous system is inevitably damaged in the course of the disease in many patients and the proportion of affected patients increases with disease duration. Autonomic dysfunction (AD) in MS is explained by lesions in regions responsible for autonomic regulation such as nuclei in the periventricular region of fourth ventricle in the brainstem as well as medullar lesions. Reports about frequency of AD in MS patients vary notably between groups. Nevertheless its impact on quality of life is substantial but, unfortunately, often overlooked. The aim of this article is to present a concise review of various symptoms and signs of autonomic system dysfunction in MS.

The rise of mortality from mental and neurological diseases in Europe, 1979-2009: observational study

Background

We studied recent trends in mortality from seven mental and neurological conditions and their determinants in 41 European countries.

Methods

Age-standardized mortality rates were analysed using standard methods of descriptive epidemiology, and were related to cultural, economic and health care indicators using regression analysis.

Results

Rising mortality from mental and neurological conditions is seen in most European countries, and is mainly due to rising mortality from dementias. Mortality from psychoactive substance use and Parkinson’s disease has also risen in several countries. Mortality from dementias has risen particularly strongly in Finland, Iceland, Malta, Netherlands, Spain, Sweden and the United Kingdom, and is positively associated with self-expression values, average income, health care expenditure and life expectancy, but only the first has an independent effect.

Conclusions

Although trends in mortality from dementias have probably been affected by changes in cause-of-death classification, the high level of mortality from these conditions in a number of vanguard countries suggests that it is now among the most frequent causes of death in high-income countries. Recognition of dementias as a cause of death, and/or refraining from life-saving treatment for patients with dementia, appear to be strongly dependent on cultural values.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2458-14-840) contains supplementary material, which is available to authorized users.

Dramatically changing rates and reasons for hospitalization in multiple sclerosis

OBJECTIVE

We aimed to describe hospitalizations in the multiple sclerosis (MS) population, and to evaluate temporal trends in hospitalizations in the MS population compared to the general population.

METHODS

Using population-based administrative data, we identified 5,797 persons with MS and a matched general population cohort of 28,769 persons. Using general linear models, we evaluated temporal trends in hospitalization rates and length of stay in the 2 populations over the period 1984-2011.

RESULTS

In 1984 the hospitalization rate was 35 per 100 person-years in the MS population and 10.5 in the matched population (relative risk [RR] 3.33; 95% confidence interval: 1.67-6.64). Over the study period hospitalizations declined 75% in the MS population but only 41% in the matched population. The proportion of hospitalizations due to MS declined substantially from 43.4% in 1984 to 7.8% in 2011. The 3 most common non-MS-related reasons for admission in the MS population were diseases of the digestive, genitourinary, and circulatory systems. Admissions for bacterial pneumonia, influenza, urinary tract infections, and pressure ulcers occurred more often in the MS population than in the general population, while admissions for circulatory system disease and neoplasms occurred less often. Older age, male sex, and lower socioeconomic status were associated with increased hospitalization rates for non-MS-related reasons.

CONCLUSIONS

Although hospitalization rates have declined dramatically in the MS population over the last quarter century, they remain higher than in the general population. Admissions for MS-related reasons now constitute only a small proportion of the reasons for hospitalization.

Intensive care unit admission in multiple sclerosis: increased incidence and increased mortality

OBJECTIVE

To compare the incidence of, and mortality after, intensive care unit (ICU) admission as well as the characteristics of critical illness in the multiple sclerosis (MS) population vs the general population.

METHODS

We used population-based administrative data from the Canadian province of Manitoba for the period 1984 to 2010 and clinical data from 93% of admissions to provincial high-intensity adult ICUs. We identified 5,035 prevalent cases of MS and a cohort from the general population matched 5:1 on age, sex, and region of residence. We compared these populations using incidence rates and multivariable regression models adjusting for age, sex, comorbidity, and socioeconomic status.

RESULTS

From January 2000 to October 2009, the age- and sex-standardized annual incidence of ICU admission among prevalent cohorts was 0.51% to 1.07% in the MS population and 0.34% to 0.51% in matched controls. The adjusted risk of ICU admission was higher for the MS population (hazard ratio 1.45; 95% confidence interval [CI] 1.19-1.75) than for matched controls. The MS population was more likely to be admitted for infection than the matched controls (odds ratio 1.82; 95% CI 1.10-1.32). Compared with the matched controls admitted to ICUs, 1-year mortality was higher in the MS population (relative risk 2.06; 95% CI 1.32-3.07) and was particularly elevated in patients with MS who were younger than 40 years (relative risk 3.77; 95% CI 1.45-8.11). Causes of death were MS (9.3%), infections (37.0%), and other causes (52.9%).

CONCLUSIONS

Compared with the general population, the risk of ICU admission is higher in MS, and 1-year mortality after admission is higher. Greater attention to preventing infection and managing comorbidity is needed in the MS population.

Factors associated with health-related quality of life among older people with multiple sclerosis

BACKGROUND

This study was conducted to determine which factors (clinical and demographic) are associated with mental and physical health-related quality of life (HRQOL) among people with multiple sclerosis (MS) aged 60 years and older.

METHODS

Data were collected at four MS centers on Long Island, New York, from a total of 211 patients. Three surveys were administered that collected demographic information and included validated questionnaires measuring quality of life (QOL), cognition, depression, and disability. Multivariate linear regression analyses examined the relationship between patient demographics and scores on standardized scales measuring mental and physical HRQOL (Multiple Sclerosis Quality of Life-54). Variables included in the regression models were selected on the basis of the Andersen Healthcare Utilization model. This framework encompasses the multiple influences on health status, including predisposing characteristics, enabling resources, need, and health behavior.

RESULTS

We found that mental HRQOL was negatively associated with having a high school education or less, risk of neurologic impairment, physical disability, and depression. No variables were positively associated with mental HRQOL. Physical HRQOL was negatively associated with risk of neurologic impairment, physical disability, depression, and the comorbidity of thyroid disease. However, patient employment and, surprisingly, being widowed were positively associated with physical HRQOL. These findings are consistent with those of similar studies among younger patients in which lower HRQOL was associated with increased disability, depression, risk of neurologic impairment, and lower levels of education.

CONCLUSIONS

The findings that patient employment and being widowed were associated with better physical HRQOL suggest that older patients have the ability to adapt and adjust to the challenges of MS over time. Clinicians should regularly screen for HRQOL in older patients with MS.

Common mechanisms of compensatory respiratory plasticity in spinal neurological disorders

In many neurological disorders that disrupt spinal function and compromise breathing (e.g. ALS, cervical spinal injury, MS), patients often maintain ventilatory capacity well after the onset of severe CNS pathology. In progressive neurodegenerative diseases, patients ultimately reach a point where compensation is no longer possible, leading to catastrophic ventilatory failure. In this brief review, we consider evidence that common mechanisms of compensatory respiratory plasticity preserve breathing capacity in diverse clinical disorders, despite the onset of severe pathology (e.g. respiratory motor neuron denervation and/or death). We propose that a suite of mechanisms, operating at distinct sites in the respiratory control system, underlies compensatory respiratory plasticity, including: (1) increased (descending) central respiratory drive, (2) motor neuron plasticity, (3) plasticity at the neuromuscular junction or spared respiratory motor neurons, and (4) shifts in the balance from more to less severely compromised respiratory muscles. To establish this framework, we contrast three rodent models of neural dysfunction, each posing unique problems for the generation of adequate inspiratory motor output: (1) respiratory motor neuron death, (2) de- or dysmyelination of cervical spinal pathways, and (3) cervical spinal cord injury, a neuropathology with components of demyelination and motor neuron death. Through this contrast, we hope to understand the multilayered strategies used to "fight" for adequate breathing in the face of mounting pathology.

Incidence of scleritis and episcleritis: results from the Pacific Ocular Inflammation Study

PURPOSE

To ascertain the incidence of scleritis and episcleritis in a Hawaiian population and describe variations by age, sex, and race.

DESIGN

Retrospective, population-based cohort study.

METHODS

All electronic medical records for enrollees in Kaiser Permanente Hawaii (n = 217,061) from January 1, 2006 to December 31, 2007 were searched for International Classification of Diseases, 9th Edition (ICD-9) codes associated with ocular inflammation. Chart review was conducted to verify a clinical diagnosis of scleritis or episcleritis. Confirmed cases were used to calculate incidence rates per 100,000 person-years. Ninety-five percent confidence intervals (CI) were calculated for each incidence rate, including age-, sex-, and race-specific rates, using bias-corrected Poisson regression. To assess for confounding, a multivariate analysis adjusting for age, sex, and race was also performed.

RESULTS

Of 217,061 eligible patients, 17 incident scleritis cases and 93 incident episcleritis cases were confirmed. The overall incidence rates of scleritis and episcleritis were 4.1 (95% CI: 2.6-6.6) and 21.7 (95% CI: 17.7-26.5) cases per 100,000 person-years, respectively. Women were overrepresented among scleritis patients (P = .049). Pacific Islanders were the most underrepresented racial group among cases of scleritis and episcleritis (P = .006, P = .001). Blacks had the highest incidence of scleritis (P = .004).

CONCLUSIONS

These results provide a population-based estimate of the incidence of scleritis and episcleritis in a diverse population and highlight differences in patients' demographic characteristics. Differences in incidence by sex and race raise questions about genetic and environmental influences on the development of these conditions.

Mortality in patients with multiple sclerosis

Mortality in patients with multiple sclerosis (MS) is significantly increased compared with the general population. Many questions concerning survival in MS are still unanswered due to the difficulty of comparing information collected at different times and in different geographic areas. The increasing incidence of MS, the improvement in care of the chronically disabled, and different methodologies may explain the lack of coherence among studies' results. Reported times to death from birth and from disease onset/diagnosis are highly variable. Patients older at onset or with primary progressive course have shorter survival; however, data on sex and mortality are contradictory. Changes in sex ratio in MS over time represent one possible explanation. MS is the main cause of death in ≥50% of patients and the incidence of deaths not due to MS varies among countries. Particularly, suicide is substantially increased in patients with MS, and, despite its varying incidence, mainly due to "cultural bias," it should be considered an MS-related cause of death. Recent results of the long-term follow-up study of interferon-β-1b demonstrated a significant reduction of mortality among treated patients. Notwithstanding its long latency, mortality is therefore an unambiguously valid long-term outcome in randomized controlled trials. It usefully combines the net impact of treatment efficacy on longevity and adverse events, which may reduce it.

Prevalence and incidence of ischemic heart disease in multiple sclerosis: A population-based validation study

BACKGROUND

Studies suggest an altered risk of ischemic heart disease (IHD) in multiple sclerosis (MS), but data are limited. We aimed to validate and apply administrative case definitions to estimate the incidence and prevalence of IHD in MS.

METHODS

Using administrative data we identified persons with incident MS (MSPOP) and a matched general population (GPOP) cohort. We developed case definitions for IHD using ICD-9/10 codes and prescription claims, compared them to medical records, then applied them to evaluate the incidence and prevalence of IHD.

RESULTS

Agreement between medical records and the administrative definition using ≥1 hospital or ≥2 physician claims over 5 years was moderate (kappa=0.66; 95% CI: 0.42-0.90). In 2005, the age-standardized prevalence of IHD was 6.77% (95% CI: 5.48-8.07%) in the MSPOP and 6.11% (95% CI: 5.56-6.66%) in the GPOP. The prevalence of IHD was higher in the MSPOP than the GPOP among persons aged 20-44 years (prevalence ratio 1.87; 95% CI: 1.65-2.12) and aged 45-59 years (prevalence ratio 1.21; 95% CI: 1.08-1.35). The incidence of IHD was also higher in the MSPOP (incidence rate ratio 1.24; 95% CI: 0.97-1.59).

CONCLUSIONS

More than 5% of the MSPOP has IHD. The incidence of IHD was higher than expected in persons aged <60 years. Further evaluation of this issue is warranted.

Cervical spinal demyelination with ethidium bromide impairs respiratory (phrenic) activity and forelimb motor behavior in rats

Although respiratory complications are a major cause of morbidity/mortality in many neural injuries or diseases, little is known concerning mechanisms whereby deficient myelin impairs breathing, or how patients compensate for such changes. Here, we tested the hypothesis that respiratory and forelimb motor functions are impaired in a rat model of focal dorsolateral spinal demyelination (ethidium bromide, EB). Ventilation, phrenic nerve activity and horizontal ladder walking were performed 7-14 days post-C2 injection of EB or vehicle (SHAM). EB caused dorsolateral demyelination at C2-C3 followed by significant spontaneous remyelination at 14 days post-EB. Although ventilation did not differ between groups, ipsilateral integrated phrenic nerve burst amplitude was significantly reduced versus SHAM during chemoreceptor activation at 7 days post-EB but recovered by 14 days. The ratio of ipsi- to contralateral phrenic nerve amplitude correlated with cross-sectional lesion area. This ratio was significantly reduced 7 days post-EB versus SHAM during baseline conditions, and versus SHAM and 14-day groups during chemoreceptor activation. Limb function ipsilateral to EB was impaired 7 days post-EB and partially recovered by 14 days post-EB. EB provides a reversible model of focal, spinal demyelination, and may be a useful model to study mechanisms of functional impairment and recovery via motor plasticity, or the efficacy of new therapeutic interventions to reduce severity or duration of disease.

Cause of death in MS: long-term follow-up of a randomised cohort, 21 years after the start of the pivotal IFNβ-1b study

OBJECTIVES

Compared with controls, multiple sclerosis (MS) patients die, on average, 7-14 years prematurely. Previously, we reported that, 21 years after their participation in the pivotal randomised, controlled trial (RCT) of interferon β-1b, mortality was reduced by 46-47% in the two groups who received active therapy during the RCT. To determine whether the excessive deaths observed in placebo-treated patients was due to MS-related causes, we analysed the causes-of-death (CODs) in these three, randomised, patient cohorts.

DESIGN

Long-term follow-up (LTF) of the pivotal RCT of interferon β-1b.

SETTING

Eleven North American MS-centres participated.

PARTICIPANTS

In the original RCT, 372 patients participated, of whom 366 (98.4%) were identified after a median of 21.1 years from RCT enrolment.

INTERVENTIONS

Using multiple information sources, we attempted to establish COD and its relationship to MS in deceased patients.

PRIMARY OUTCOME

An independent adjudication committee, masked to treatment assignment and using prespecified criteria, determined the likely CODs and their MS relationships.

RESULTS

Among the 366 MS patients included in this LTF study, 81 deaths were recorded. Mean age-at-death was 51.7 (±8.7) years. COD, MS relationship, or both were determined for 88% of deaths (71/81). Patients were assigned to one of nine COD categories: cardiovascular disease/stroke; cancer; pulmonary infections; sepsis; accidents; suicide; death due to MS; other known CODs; and unknown COD. Of the 69 patients for whom information on the relationship of death to MS was available, 78.3% (54/69) were adjudicated to be MS related. Patients randomised to receive placebo during the RCT (compared with patients receiving active treatment) experienced an excessive number of MS-related deaths.

CONCLUSIONS

In this long-term, randomised, cohort study, MS patients receiving placebo during the RCT experienced greater all-cause mortality compared to those on active treatment. The excessive mortality in the original placebo group was largely from MS-related causes, especially, MS-related pulmonary infections.

Ambulatory activity in individuals with multiple sclerosis

BACKGROUND AND PURPOSE

Specific characteristics of physical activity limitations associated with multiple sclerosis (MS) remain unclear. Our purpose was to examine the impact of MS disability on physical activity behaviors involving ambulation. We also explored relationships among ambulatory activity parameters and clinical measures of gait, balance, and fatigue.

METHODS

Twenty-one adults with MS participated: 11 without ambulatory limitation (Expanded Disability Status Scale [EDSS] score ≤ 4.5) and 10 with ambulatory limitation (EDSS score > 4.5). Participants wore a step activity monitor for up to 7 days. Daily values were calculated for parameters indicative of (1) overall activity, (2) upper limits of activity output, and (3) activity work-rest cycles. Clinical measures included Multiple Sclerosis Walking Scale, Timed 25-Foot Walk, Timed Up and Go test, 6-Minute Walk, Dynamic Gait Index, Berg Balance Scale, Activities-specific Balance Confidence Scale, and Modified Fatigue Impact Scale. Statistical analyses were conducted using nonparametric tests.

RESULTS

Participants without limitation were more active, demonstrated higher upper limits of activity output, and had longer activity bouts than participants with limitation (P < 0.05). Only 1 participant averaged more than 100 steps per minute over a 30-minute period. Of the ambulatory activity parameters, daily step count was most strongly related to gait and balance measures. Of the clinical measures, EDSS and Multiple Sclerosis Walking Scale scores were most strongly related to daily step count.

CONCLUSION

Individuals with MS are not necessarily sedentary, but few may achieve recommended daily physical activity levels. Ambulatory activity characteristics revealed new insights into physical activity limitations in MS. The study findings suggest that disability status should direct physical activity interventions.

Six-minute walk test for persons with mild or moderate disability from multiple sclerosis: performance and explanatory factors

PURPOSE

The primary purpose of this study was to determine the extent to which health factors, functional measures, and pulmonary impairment explain performance on 6-Minute Walk Test (6MWT) distance in ambulatory persons with multiple sclerosis (MS). Another purpose was to determine the effect of disability and age on 6MWT performance and explanatory factors.

METHODS

A cross-sectional study design was used to evaluate factors that explain performance on the 6MWT in 64 community-dwelling persons with MS-related disability (Expanded Disability Status Scale [EDSS] 3.8±1.6). Of the 64 participants, 43 (67.2%) exhibited mild disability (EDSS <4.0) and 21 (32.8%) had moderate disability (EDSS 4.0-6.5). A regression analysis compared 6MWT performance to measures of health factors (EDSS, number of medications, number of comorbidities, resting HR, systolic and diastolic blood pressure [BP]); physical performance (functional stair test [FST], sit-to-stand test [SST], static standing balance [BAL], Fatigue Severity Scale [FSS], Activities-specific Balance Confidence [ABC] Scale); and pulmonary function (forced expiratory volume in 1 second [FEV(1)], forced vital capacity [FVC], maximal voluntary ventilation [MVV], maximal inspiratory pressure [MIP], maximal expiratory pressure [MEP]).

RESULTS

EDSS, ABC, FST, SST, BAL, MVV, MIP, and MEP were significantly associated with 6MWT distance after adjusting for age. Multiple step-wise linear regression analysis revealed that ABC, FST, and BAL were significant and independent explanatory factors of 6MWT distance. ABC and FST explained 75% of the variance in 6MWT performance (R(2)=0.75). Curvilinear regression analysis revealed that the FST is the most significant explanatory factor for 6MWT distance, explaining 79% of the variance (R(2)=0.79).

CONCLUSIONS

6MWT performance in persons with MS was explained by balance confidence (ABC) and stair-climbing ability (FST). The ABC and FST may be practical clinical measures for explaining walking ability and determining risk for disablement in persons with MS.

The economic burden of Medicare-eligible patients by multiple sclerosis type

OBJECTIVE

Although the global rate of multiple sclerosis (MS) is low, a few studies have documented high costs. Costs are highly variable depending on MS stage. This study was designed to assess the economic burden of Medicare-eligible patients by MS type in the United States using a claims-based classification algorithm to examine cost variation by disease stage.

METHODS

A sample of 2003 to 2006 Medicare patients was selected. Cases were classified as pre-existing progressive MS or pre-existing relapsing-remitting MS (RRMS); the latter were further subdivided into relapsing, remitting, or stable.

RESULTS

The sample had 5044 MS subjects, of whom 34.4% had prevalent progressive MS and 65.6% had prevalent RRMS. There were many chronic, comorbid conditions. The mean all-cause Medicare expenditures (not including self-administered medications) per person-year for MS in 2006 were $23,630 for prevalent progressive patients and $5887 for prevalent RRMS patients. Within the RRMS type, Medicare expenditures per person per month in 2006 were $1418 for relapsing patients, $608 for remitting patients, and $331 for stable patients.

CONCLUSIONS

There are substantial cost advantages to Medicare for keeping RRMS patients in a stable health state and in keeping them from advancing in disability severity. The overall cost advantage would be diminished by the large cost burden of comorbidity, which would likely remain fixed with improved MS therapies.

Effects of a 10-week inspiratory muscle training program on lower-extremity mobility in people with multiple sclerosis: a randomized controlled trial

Pulmonary muscle weakness is common in ambulatory people with multiple sclerosis (MS) and may lead to deficits in mobility function. The purpose of this study was to examine the effect of a 10-week home-based exercise program using an inspiratory muscle threshold trainer (IMT) on the results of four lower-extremity physical performance tests in people with MS. The study design was a two-group (experimental-control), pretest-posttest study. Outcome measures consisted of pulmonary function measures including maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), and maximal voluntary ventilation (MVV), and the following lower-extremity physical performance measures: the 6-Minute Walk (6MW) distance, gait velocity (GV), the Sit-to-Stand Test (SST), the Functional Stair Test (FST), and a balance test (BAL). A total of 46 ambulatory participants (Expanded Disability Status Scale [EDSS] score, 2.0-6.5) with MS were randomly assigned to an intervention group (mean EDSS score, 4.1) that received 10 weeks of home-based inspiratory muscle training or a nontreatment control group (mean EDSS score, 3.2). Of the original 46 participants, 20 intervention group participants and 19 control group participants completed the study. Compared with the control group, the intervention group made significantly greater gains in inspiratory muscle strength (P = .003) and timed balance scores (P = .008). A nonsignificant improvement in 6MW distance (P = .086) was also noted in the IMT-trained group as compared with the control group. This is the first study directly linking improvement in respiratory function to improvement in physical performance function in people with mild-to-moderate disability due to MS.

Causes of death among patients with multiple sclerosis

BACKGROUND

Several studies show a high mortality risk among patients with multiple sclerosis (MS).

OBJECTIVES

In this study, mortality and underlying causes of death were analysed among patients with MS diagnosed between 1964-1993 in Finland (n = 1595).

METHODS

Standardized mortality ratios (SMRs) were calculated for both genders. The follow-up was based on linkage to the national computerized Cause-of-Death Register of Statistics Finland.

RESULTS

Altogether, 464 deaths were recorded by the end of 2006. The SMR as compared with the general population among females was 3.4 (95% confidence interval 3.0-3.9) and among males 2.2 (1.9-2.6). In total, 270 patients (58%) died from MS; only one of these deaths occurred during the first 2 years after the MS diagnosis. Mortality was also increased for other natural causes of death (n = 160) in patients followed for more than 10 years (SMR 1.4, 1.2-1.7), with a significant increase in deaths from influenza (29, 6.0-85), pneumonia (4.7, 2.5-8.0) and gastrointestinal causes (4.4, 2.3-7.7). The SMR for violent causes was 1.2 (0.7-1.9) and for alcohol-related deaths 0.2 (0.02-0.7). The SMR for suicides was 1.7 (0.9-2.7).

CONCLUSIONS

The MS population has an increased disease mortality, while the increase in the risk of accidents and suicides is not significantly increased among patients with MS in Finland.

Ventilatory impairment in the dysmyelinated Long Evans shaker rat

Although respiratory complications significantly contribute to morbidity/mortality in advanced myelin disorders, little is known concerning mechanisms whereby dysmyelination impairs ventilation, or how patients compensate (i.e. plasticity). To establish a model for studies concerning mechanisms of ventilatory impairment/compensation, we tested the hypotheses that respiratory function progressively declines in a model of CNS dysmyelination, the Long Evans shaker rat (les). The observed impairment is associated with abnormal inspiratory neural output. Minimal myelin staining was found throughout the CNS of les rats, including the brainstem and cervical bulbospinal tracts. Ventilation (via whole-body plethysmography) and phrenic motor output were assessed in les and wild-type (WT) rats during baseline, hypoxia (11% O(2)) and hypercapnia (7% CO(2)). Hypercapnic ventilatory responses were similar in young adult les and WT rats (2 months old); in hypoxia, rats exhibited seizure-like activity with sustained apneas. However, 5-6 month old les rats exhibited decreased breathing frequencies, mean inspiratory flow (V(T)/T(I)) and ventilation (V (E)) during baseline and hypercapnia. Although phrenic motor output exhibited normal burst frequency and amplitude in 5-6 month old les rats, intra-burst activity was abnormal. In WT rats, phrenic activity was progressive and augmenting; in les rats, phrenic activity was decrementing with asynchronized, multipeaked activity. Thus, although ventilatory capacity is maintained in young, dysmyelinated rats, ventilatory impairment develops with age, possibly through discoordination in respiratory motor output. This study is the first reporting age-related breathing abnormalities in a rodent dysmyelination model, and provides the foundation for mechanistic studies of respiratory insufficiency and therapeutic interventions.