Prognostic factors for life expectancy in multiple sclerosis analysed by Cox-models

Prediction of Conversion from Clinically Isolated Syndrome to Multiple Sclerosis According to Baseline Characteristics: A Prospective Study

Objective

Clinically isolated syndrome (CIS) is a clinical state that proceeds with inflammation and demyelination, suggestive of multiple sclerosis (MS) in the central nervous system in the absence of other alternative diagnoses. The purpose of this study was to determine in a prospective cohort, the predictor factors in conversion from CIS to MS on the basis of clinical, magnetic resonance (MR) imaging and cerebrospinal fluid (CSF) findings.

Methods

Forty-one CIS patients were included in this study and followed up for at least two years.

Results

Clinically, polysymptomatic or sensorial involvement, good prognostic factors and complete response to pulse therapy were found to be of prognostic value in conversion to MS. A greater presence of oligoclonal bands in CSF was identified in the converted group (92.8%). In terms of localization, presence of callosal lesion (71.4%), periventricular lesion (97.1%), Gd-enhanced lesion (48.6%), black hole (54.2%) and brainstem lesion (57.1%) was statistically significant in terms of conversion to MS.

Conclusion

A carefully performed neurological assessment of symptoms and signs, and evaluation of lesions on MR combined with CSF findings are important for identifying the risk of conversion to MS. This information may be useful when considering treatment in CIS patients instead of waiting for conversion to MS.

Survival and cause of death in multiple sclerosis: a 60-year longitudinal population study

OBJECTIVE

Survival and causes of death (COD) in multiple sclerosis (MS) provide ultimate endpoints. We aimed to investigate survival and COD in a 60-year population-based MS cohort compared with the general population.

METHODS

All patients with incident multiple sclerosis (MS) (N=1388) with onset during 1953-2012 in Hordaland County, Western Norway, were included. Data were obtained from patient records at Haukeland University Hospital and linked to the Norwegian COD registry. Survival adjusted for sex, age and disease course were estimated by Kaplan-Meier analyses from birth and from disease onset. Mortality and COD in MS relative to the general population were examined by standardised mortality ratio (SMR).

RESULTS

Of 1388 patients, 291 had deceased, mainly of MS (56.4%). Median life expectancy was 74.7 years for MS and 81.8 years for the general population (p<0.001); 77.2 years for women with MS and 72.2 years for men with MS (p<0.001). Life expectancy for patients with relapsing remitting MS (RRMS) was 77.8 years and -71.4 years for primary progressive MS (PPMS) (p<0.001). Overall SMR was 2.7 (p>0.0001); 2.9 in women and 2.5 in men (p=0.0009). SMR was 2.4 in RRMS and 3.9 in PPMS (p<0.0001). SMR from disease onset during 1953-1974 was 3.1; 2.6 during 1975-1996 and 0.7 during 1997-2012 (p<0.0083). No difference in cause-specific deaths were found (p=0.0871).

CONCLUSION

We found a 7-year shorter life expectancy and almost threefold higher mortality in MS compared with the general population. A rise in survival in MS was observed during the entire observation period.

Multiple sclerosis: integration of modeling with biology, clinical and imaging measures to provide better monitoring of disease progression and prediction of outcome

Multiple Sclerosis (MS) is a major cause of neurological disability in adults and has an annual cost of approximately $28 billion in the United States. MS is a very complex disorder as demyelination can happen in a variety of locations throughout the brain; therefore, this disease is never the same in two patients making it very hard to predict disease progression. A modeling approach which combines clinical, biological and imaging measures to help treat and fight this disorder is needed. In this paper, I will outline MS as a very heterogeneous disorder, review some potential solutions from the literature, demonstrate the need for a biomarker and will discuss how computational modeling combined with biological, clinical and imaging data can help link disparate observations and decipher complex mechanisms whose solutions are not amenable to simple reductionism.

Excess Mortality in Patients with Multiple Sclerosis Starts at 20 Years from Clinical Onset: Data from a Large-Scale French Observational Study

BACKGROUND

Recent studies in multiple sclerosis (MS) showed longer survival times from clinical onset than older hospital-based series. However estimated median time ranges widely, from 24 to 45 years, which makes huge difference for patients as this neurological disease mainly starts around age 20 to 40. Precise and up-to-date reference data about mortality in MS are crucial for patients and neurologists, but unavailable yet in France.

OBJECTIVES

Estimate survival in MS patients and compare mortality with that of the French general population.

METHODS

We conducted a multicenter observational study involving clinical longitudinal data from 30,413 eligible patients, linked to the national deaths register. Inclusion criteria were definite MS diagnosis and clinical onset prior to January, 1st 2009 in order to get a minimum of 1-year disease duration.

RESULTS

After removing between-center duplicates and applying inclusion criteria, the final population comprised 27,603 MS patients (F/M sex ratio 2.5, mean age at onset 33.0 years, 85.5% relapsing onset). During the follow-up period (mean 15.2 +/- 10.3 years), 1569 deaths (5.7%) were identified; half related to MS. Death rates were significantly higher in men, patients with later clinical onset, and in progressive MS. Overall excess mortality compared with the general population was moderate (Standardized Mortality Ratio 1.48, 95% confidence interval [1.41-1.55]), but increased considerably after 20 years of disease (2.20 [2.10-2.31]).

CONCLUSIONS

This study revealed a moderate decrease in life expectancy in MS patients, and showed that the risk of dying is strongly correlated to disease duration and disability, highlighting the need for early actions that can slow disability progression.

Disability and Survival of Multiple Sclerosis in Saskatoon, Saskatchewan

Background:

A population-based prevalent group of 150 clinical definite patients ascertained on 1 January 1977, in Saskatoon, Saskatchewan, was followed for 30 years.

Objectives:

To outline the clinical characteristics, determine the levels of disability at 15, 25, 35, 40, and 45 years after onset, to estimate the survival after onset and life expectancy.

Methods:

Clinical records were maintained, and the cohort reviewed each decade for 30 years. The disability levels according to the Kurtzke Extended Disability Status Scale were recorded and survival times were estimated. SPSS and Kaplan-Meier methods were used for analysis.

Results:

On prevalence day, 1 January 1977, there were 48(32%) men and 102(68%) women, with an average age of onset of 32.2±10 years and 28.4±8.6 years. The average duration of disease was 15.7 years. On 1 January 2007, 39(26%) patients were living, 105(70%) deceased, and 6(4%) were missing The disability levels recorded in 1977 and 2007, at 15 and 45 years after onset, were mild (EDSS≤2.5), 33.3% and 8.0%; moderate (EDSS3-5.5), 17.3% and 2.7%; severe (EDSS6-7.5), 6.6% and 4.7%; maximum (EDSS8-9.5), 22.7% and 10.7%. The median survival time after onset was 33 (95% CI: 27.3-38.6) years for men and 38 (95% CI: 34.1-41.9) years for women. The median duration of life was 68.9 years for men and 69.5 years for women, and a decreased life expectancy of 7.7 and 12.8 years.

Conclusions:

Multiple sclerosis is a progressive neurological disorder and long-term survival is associated with moderate to severe disability and decreased life expectancy.

The clinical course of multiple sclerosis

Knowledge of the epidemiology and natural history of multiple sclerosis (MS) is essential for practitioners and patients to make informed decisions about their care. This knowledge, in turn, depends upon the findings from reliable studies (i.e., those which adhere to the highest methodological standards). For a clinically variable disease such as MS, these standards include case ascertainment using a population-based design; a large-sized sample of patients, who are followed for a long time-period in order to provide adequate statistical power; a regular assessment of patients that is prospective, frequent, and standardized; and the application of rigorous statistical techniques, taking into account confounding factors such as the use of disease modifying therapy or the age at clinical onset. In this chapter we review the available epidemiologic and natural history data as it relates clinical issues such as the likelihood of incomplete recovery from a first attack; the likelihood and time course of a second attack; the likelihood and time course of disease progression and the accumulation of irreversible disability; the disease prognosis based both upon the clinical nature and presentation of the first episode and upon the initial disease course; and the impact of disease on mortality. In addition, these studies provide insight to the pathophysiologic mechanisms underlying the course and prognosis of MS. Studies of the Lyon cohort have been particularly helpful in this regard and observations from this cohort have led to the hypothesis that, in large part, the accumulation of disability in MS is an age-related process, which is independent of the clinical subtype of MS (i.e., relapsing-remitting, primary progressive, secondary progressive, or relapsing progressive). And finally, we consider briefly the impact of various life events (e.g., pregnancy, infection, vaccination, trauma, and stress) on the clinical course of disease.

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.

Pre-existing central nervous system lesions negate cytokine requirements for regional experimental autoimmune encephalomyelitis development

In region-specific forms of experimental autoimmune encephalomyelitis (EAE), lesion initiation is regulated by T-cell-produced interferon-γ (IFN-γ) resulting in spinal cord disease in the presence of IFN-γ and cerebellar disease in the absence of IFN-γ. Although this role for IFN-γ in regional disease initiation is well defined, little is known about the consequences of previous tissue inflammation on subsequent regional disease, information vital to the development of therapeutics in established disease states. This study addressed the hypothesis that previous establishment of regional EAE would determine subsequent tissue localization of new T-cell invasion and associated symptoms regardless of the presence or absence of IFN-γ production. Serial transfer of optimal or suboptimal doses of encephalitogenic IFN-γ-sufficient or -deficient T-cell lines was used to examine the development of new clinical responses associated with the spinal cord and cerebellum at various times after EAE initiation. Previous inflammation within either cerebellum or spinal cord allowed subsequent T-cell driven inflammation within that tissue regardless of IFN-γ presence. Further, T-cell IFN-γ production after initial lesion formation exacerbated disease within the cerebellum, suggesting that IFN-γ plays different roles at different stages of cerebellar disease. For the spinal cord, IFN-γ-deficient cells (that are ordinarily cerebellum disease initiators) were capable of driving new spinal-cord-associated clinical symptoms more than 60 days after the initial acute EAE resolution. These data suggest that previous inflammation modulates the molecular requirements for new neuroinflammation development.

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.

Fingolimod (FTY720): a recently approved multiple sclerosis drug based on a fungal secondary metabolite

Fingolimod (Gilenya; FTY720), a synthetic compound based on the fungal secondary metabolite myriocin (ISP-I), is a potent immunosuppressant that was approved (September 2010) by the U.S. FDA as a new treatment for multiple sclerosis (MS). Fingolimod was synthesized by the research group of Tetsuro Fujita at Kyoto University in 1992 while investigating structure-activity relationships of derivatives of the fungal metabolite ISP-I, isolated from Isaria sinclairii. Fingolimod becomes active in vivo following phosphorylation by sphingosine kinase 2 to form fingolimod-phosphate, which binds to extracellular G protein-coupled receptors, sphingosine 1-phosphates, and prevents the release of lymphocytes from lymphoid tissue. Fingolimod is orally active, which is unique among current first-line MS therapies, and it has the potential to be used in the treatment of organ transplants and cancer. This review highlights the discovery and development of fingolimod, from an isolated lead natural product, through synthetic analogues, to an approved drug.

Gender issues in multiple sclerosis: an update

Although multiple sclerosis (MS) affects both women and men, women are more susceptible to MS than men. Accumulating evidence indicates that the incidence and prevalence of MS is increasing, more so in women than in men. Owing to pregnancy, differing hormonal states and distinct social roles, the impact of MS differs between women and men. Since Patricia K Coyle published a review on gender issues in MS, multiple studies have added to the body of knowledge. This update will summarize the current thinking on gender-related issues in MS and we will address incidence and prevalence, hormonal factors, pregnancy and breastfeeding, genetics, course and prognosis, imaging, treatment and psychosocial aspects. Future progression within this field will help elucidate the cause of and define the treatment of 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.

Clinical and electronystagmographical evaluation of vestibular symptoms in relapsing remitting multiple sclerosis

OBJECTIVE

Multiple sclerosis (MS) may give rise to a variety of clinical signs and symptoms including vertigo and/or other problems related with equilibrium. In this study, we aimed to evaluate clinical and electronystagmographical (ENG) characteristics of relapsing remitting MS (RRMS) patients.

DESIGN

This is a prospective controlled study consisting of 30 patients who were diagnosed as definite RRMS according to McDonald's diagnostic criteria and 30 healthy individuals.

SETTING

Entire population of patients were examined and followed up at the same tertiary centre during the period of September 2003 and March 2005. Clinical examination and detailed electronystagmographic investigations were performed in each group.

METHODS

Vestibular laboratory testing was carried out by a computerized ENG system. All ENG subtests including tracking, saccade, optokinetic, gaze, positional and Dix-Hallpike tests were performed in each group but caloric, which is relatively an invasive test, was performed only in the patient group.

MAIN OUTCOME MEASURES

We aimed to find the ratio of abnormal tests indicating, central and/or peripheral pathology in ENG. We also analyzed the correlation of total number of abnormal tests in ENG with clinical parameters.

RESULTS

Differences of ENG abnormality indicating central and/or peripheral pathology and ENG abnormality indicating only central pathology between the two groups were statistically significant. Correlation of total number of abnormal tests in ENG with EDSS score was statistically significant.

CONCLUSION

ENG is sensitive in detecting the vestibular system involvement in RRMS patients if all subtests are performed and evaluated in detail with clinical symptoms and signs.

Excess mortality and cause of death in a cohort of Norwegian multiple sclerosis patients

There are few studies of long-term, cause-specific mortality in multiple sclerosis (MS) relating to population mortality. Our objective was to study survival, excess mortality and causes of death in a cohort of patients with a long history of MS. Patients living in Oslo with definite MS and onset during 1940—80 were included in 2006. Causes of death and mortality in the general population were obtained from the Cause of Death Registry of Statistics Norway. Of the 386 patients included in the study, 263 (68%) had died at inclusion. Median survival from onset was 35 years (Kaplan—Meier: 95% confidence interval 33—37). Primary progressive MS was associated with shorter survival, but mean age at death was similar for relapsing-remitting and primary progressive MS patients. The most frequent underlying cause of death was MS (50%), and infection was often registered as a contributory cause (56%). The all-cause standardized mortality ratio was 2.47. Excess mortality was most marked during the second decade after onset of MS. We conclude that infections are probably the main cause of death in patients with MS, but the frequency is underestimated due to misleading information on death certificates. Excess mortality in patients with MS first appeared during the second decade of the disease. Survival seems to be age-dependent rather than related to disease course.

Long-term follow-up of benign multiple sclerosis in Hordaland County, Western Norway

Objective

To study the frequency of benign multiple sclerosis (MS) after 20 years disease duration and identify early clinical and demographic prognostic factors of a benign course.

Methods

A population-based cohort including all 230 MS patients with clinical disease onset during 1976–1986 in Hordaland County, Western Norway was followed up with clinical examination in 1995 and 2003. Benign MS was defined as an Expanded Disability Status Scale (EDSS) score ≤3.0, at least 10 years after disease onset.

Results

A relapsing–remitting disease course at onset, female gender, and younger age at onset were significantly associated with a benign course, but could only explain 23.0% of the variation in the benign course. A low annual relapse rate was also associated with a benign course. When including this variable in the model, 42.3% of the variation could be explained. The number of benign MS cases decreased significantly from 37.6% in 1995 to 24.2% in 2003.

Conclusion

Benign MS is frequently a temporary condition. Only a small part of the variation in the long-term benign course could be explained by clinical data present in the early phase of the disease. With several new emerging therapies in MS, the need for more reliable prognostic factors is increasing, to improve and individualize patient treatment.

The clinical epidemiology of multiple sclerosis

A comprehensive knowledge of the natural course and prognosis of multiple sclerosis is of utmost importance for a physician to make it affordable in simple descriptive terms to a patient when personal and medical decisions are to be taken. It is still topical because the currently acknowledged disease-modifying agents only marginally alter the overall prognosis of the disease. It provides reference for evaluating the efficacy of a therapeutic intervention in clinical trials; clues for public health services, health insurance companies, and pharmaceutical industry in their respective activities; and insights into the pathophysiology and the treatment of multiple sclerosis. Precise, consistent, and reliable data from appropriate cohorts have become available and knowledge is fairly comprehensive.

Survival and cause of death in multiple sclerosis: results from a 50-year follow-up in Western Norway

Background

Survival time among patients with multiple sclerosis (MS) has varied considerably according to previous reports.

Objectives

Survival and cause of death were analyzed among all patients with MS (878) with onset of MS in Hordaland County, Western Norway during 1953–2003, of whom 198 were dead at follow-up on January 1, 2005.

Methods

Standardized mortality ratios (SMRs) and relative mortality ratios (RMRs) were calculated based on observed mortality in MS and expected mortality.

Results

Median survival from onset was 41 years versus 49 years in the corresponding population, and mortality (SMR) was 2.7-fold increased in MS. The median survival was 43 years among women and 36 years among men, but women had higher relative mortality, when compared with the corresponding population, than men (RMR = 1.40). The median survival time was 45 years among young-onset patients (21–30 years) and 23 years among older-onset patients (51–60 years), but young-onset patients had higher relative mortality than older-onset patients, as shown by a significant reduction by 10-year interval of age at onset (RMR = 0.65). Median survival from onset was longer (43 years) among relapsing–remitting MS than primary progressive MS ([PPMS]; 49 years), and the relative mortality was higher in the PPMS group, (RMR = 1.55). According to death certificates, 57% died from MS.

Conclusion

Female patients and patients with young onset had longer median time to death but higher relative risk of dying compared with the corresponding population. PPMS had both shorter median time to death from onset and a higher relative risk of dying.

Mortality in multiple sclerosis: a review

This work was undertaken to evaluate studies on mortality caused by multiple sclerosis (MS), to evaluate if useful inferences can be drawn from survival studies that can be applied to clinical practice. A literature search was carried out to find epidemiological studies on MS prognosis, survival, mortality and causes of death relevant to our aim. The World Health Organization (WHO) reports on worldwide cause-specific mortality were also considered. Studies were evaluated according to the duration of the follow-up study, the year of publication and the methodology used. We evaluated MS survival from a methodological point of view and considered if time trends could be drawn from study results. We conclude that mortality is only slightly higher in MS patients when compared with that in the general population. Mortality is higher particularly for older patients and those with longer disease duration.

Campath 1-H treatment in patients with aggressive relapsing remitting multiple sclerosis

Campath 1-H (Alemtuzumab) is a humanised monoclonal antibody which targets the CD52 antigen, a low molecular weight glycoprotein present on the surface of most lymphocyte lineages, causing complement mediated lysis and rapid and prolonged T lymphocyte depletion. Following encouraging initial data from other centres we report our open label experience of using Campath 1-H as a treatment in aggressive relapsing multiple sclerosis in a consecutive series of 39 highly selected patients treated across three regional centres and followed for a mean of 1.89 years. The mean annualised relapse rate fell from 2.48 pre treatment to 0.19 post treatment with 29% of documented relapses observed in the 12 weeks following initial infusion. Mean change in EDSS was -0.36 overall and -0.15 in those patients completing > or =1 year of follow- up. Eighty-three per cent of patients had stable or improved disability following treatment. Infusion related side effects were common including rash, headache and pyrexia but were usually mild and self limiting. Transient worsening of pre-existing neurological deficits during infusion was observed in 3 patients. 12 patients developed biochemical evidence of autoimmune dysfunction, 2 patients developed thyroid disease and 1 patient autoimmune skin disease. We conclude that relapse rates fall following Campath 1-H. Whilst side effects were common these were normally self limiting or easily managed, suggesting Campath 1-H may be of use in the treatment of very active relapsing remitting multiple sclerosis.

Long-term survival of patients with multiple sclerosis in West France

In France no data have been published about comparing survival in multiple sclerosis (MS) patients with the general French population. We estimated survival probabilities in MS patients from a major centre for MS in West France. We also compared MS survival with the general population and assessed prognostic parameters. All patients with MS onset after January 1976 and classified as dead or alive on 1 January 2004 were included. One thousand eight-hundred and seventy-nine patients (sex ratio W: M 2.3; relapsing/progressive onset 77.4%/22.6%) fulfilled these criteria, disease duration ranged from one to 28 years. By 2004, 68 patients died (51 due to MS) and the 15 and 25-year survival probabilities were 96% and 88%. Male gender, progressive course (either primary or secondary), polysymptomatic onset, and increased annual relapse rate during the first two years of MS were related to a worse prognosis. After a mean follow-up duration of 12.7 years since clinical onset, MS increased the number of deaths compared with the general population. However taking into account disability status, we found that less disabled MS patients had a better survival and highly disabled patients a worse survival (eight-fold increase of mortality) compared with the French population.

Disability evolution in multiple sclerosis: how to deal with missing transition times in the Markov model?

Markov modeling of disability progression in multiple sclerosis requires knowledge of all times of transitions from a given level of disability to the next level, but such data are often missing. We address methodological challenges due to partly missing transition times. To estimate the effects of prognostic factors on the risk of transitions between three consecutive disability levels, two methods were used to deal with missing data. Listwise deletion limited the analysis to subjects with complete data. Multiple imputation of missing data revealed that data were missing at random (MAR mechanism) and imputed the missing transition times from the Weibull model. The results were then compared with the full data set with the actual times established through chart review. Multiple imputation estimates were systematically closer to those from the full data set than the listwise deletion estimates.

Benign course in multiple sclerosis: a review

Since the 1950s, it has been recognized that a subgroup of multiple sclerosis (MS) patients exists that shows little or no progression in the severity of the disease over time. This group is referred to as 'benign' MS. Although a substantial amount of research in MS indicates a multifactorial background in disease severity, to date it is still difficult to predict whether the course will be benign at onset and it is difficult to find factors that influence the course of the disease over time. Maintaining or restoring neural conduction inside a central nervous system lesion seems to be the essence of staying 'benign'.

Increasing Incidence of Multiple Sclerosis in the Province of Sassari, Northern Sardinia

Sardinia is a high-risk area for multiple sclerosis (MS), with prevalence rates of 150 per 100,000 population. The study included 689 MS patients (female-male ratio 2.6) with disease onset between 1965 and 1999 in the province of Sassari. The mean annual incidence rate increased significantly from 1.1 per 100,000 population in 1965-1969 to 5.8 in 1995-1999, with no significant difference for gender and province sub-areas. The mean age at onset increased significantly during the same period from 25.7 to 30.6 years, while the proportion of patients with progressive initial course declined over time. The marked increase of MS incidence and the change of MS clinical phenotype over time cannot be explained by ascertainment bias only, thus pointing to a corresponding change in the distribution of exogenous risk factors in this highly genetically stable population.

Multiple Sclerosis

This chapter provides information on the epidemiology of multiple sclerosis (MS), the most common disabling neurological disease in young adults. It describes the clinical and pathologic features of MS and how these features pose challenges for clinical diagnosis and case definition criteria. Information is provided regarding the descriptive epidemiology of MS, including studies of incidence, prevalence, and temporal trends in MS frequency. Also included is a discussion of the interesting geographical features of the MS distribution, including MS disease clusters, the latitude gradient in disease risk, and migrant studies of individuals who move from high-risk to low-risk regions. Other sections of the chapter cover evidence regarding the infectious etiology of MS, including the important role that Epstein-Barr virus appears to play in disease susceptibility. The role of lifestyle factors is receiving increasing emphasis in MS epidemiologic studies, and evidence is summarized regarding the potential role of cigarette smoking, diet, and hormonal factors.

Comparison of two brief neuropsychological batteries in people with multiple sclerosis

BACKGROUND

We compared two brief neuropsychological batteries devised to assess people with multiple sclerosis (MS) and used them to assess the relationship between cognitive impairment and dinical characteristics.

METHODS

We administered either the Brief Repeatable Battery of Neuropsychological Tests (BRBNT) or the Screening Examination for Cognitive Impairment (SEFCI) to 213 consecutive MS outpatients and 213 individually matched controls.

RESULTS

Administration times were longer for BRBNT than SEFCI, for MS and controls (p=0.001). People with MS had lower scores in all individual tests than controls (p<0.001, BRBNT and SEFCI). By the criterion of poor performance on one or more tests, the sensitivity of BRBNT was 41.9% and that of SEFCI 31.5%. The corresponding figures by poor performance on two or more tests were 16.2% for BRBNT and 18.5% for SEFCI. The Buschke Selective Reminding and Paced Auditory Serial Addition were the tests best discriminating between people with MS and controls for BRBNT, and the Symbol Digit Modalities test for SEFCI. The only clinical variable independently associated with impaired performance on these batteries was EDSS.

CONCLUSIONS

Both cognitive batteries were well accepted and easy to administer. Administration time for SEFCI was significantly shorter than for BRBNT; however, alternative forms for serial evaluation are available only for BRBNT. The BRBNT was slightly more sensitive in detecting impairment by the criterion of poor perfomance on one or more tests. EDSS score was the only clinical variable independently associated with cognitive impairment

Disability and prognosis in multiple sclerosis: demographic and clinical variables important for the ability to walk and awarding of disability pension

OBJECTIVE

To evaluate disability and prognosis in an untreated population-based incidence cohort of multiple sclerosis (MS) patients.

METHODS

The Expanded Disability Status Scale (EDSS) score was recorded in 220 MS patients. Disease progression was assessed by life table analysis with different endpoints and multivariate Cox regression analysis was performed for evaluation of prognostic factors.

RESULTS

The probability of being alive after 15 years was 94.8 +/- 1.8% (s.e.), of managing without a wheelchair (EDSS < 7.0) 75.8 +/- 3.2%, of walking without walking assistance (EDSS<6.0) 60.3 +/- 3.6%, and of not being awarded a disability pension 46.0 +/- 3.7%. The probability of still having a relapsing-remitting (RR) course after 15 years was 62.0 +/- 4.1%. A RR course and long interval between the initial (onset) and second episode (> 3 years) predicted favorable outcome. There was also a trend towards favorable outcome in patients with optic neuritis, sensory symptoms and low age at onset but these factors were associated with the RR course. Motor symptoms and high age at onset indicated unfavorable outcome, but these factors were associated with the primary progressive course.

CONCLUSIONS

A RR course and long inter-episode intervals in the early phase of the disease were associated with a better outcome. Other onset characteristics indicating a favorable outcome were associated with the RR course while characteristics indicating an unfavorable outcome were associated with the PP course.

Performance of the SF-36, SF-12, and RAND-36 summary scales in a multiple sclerosis population

BACKGROUND

Multiple sclerosis (MS) patients accumulate both physical and mental health problems along with disease progression. Valid and sensitive outcome measures are important to measure disease effects and the effect of treatment.

OBJECTIVE

The objective of this study was to test the performance of the physical and mental summary scales of SF-36, SF-12, and RAND-36.

METHODS

The scales were evaluated by comparing the scores of a cohort of 194 MS patients with general population data and using the Expanded Disability Status Scale (EDSS) and the Incapacity Status Scale-mental as criterion variables for physical functioning and mental health.

RESULTS

All 3 physical summary scales were markedly reduced and correlated highly with the EDSS. The SF-36 mental summary score was only slightly reduced among MS patients (0.2 SD) compared with the general population, despite significantly reduced scores on all 4 health scales being most related to mental health and despite a high prevalence of mental health problems. This results from the poor physical functioning (mean scale score, 2.3 SD below the general population) and the orthogonal factor rotation used to derive independent measures of physical and mental health. Similar results were found for the SF-12. The nonorthogonal RAND-36 physical and mental summary scores were both markedly reduced. This is more compatible with the disease progression in MS and the results of the other measures of physical and mental health used in the study.

CONCLUSIONS

The SF-36 and SF-12 mental health summary scales appear to overestimate mental health in people with MS.

Multiple sclerosis in Australia: prognostic factors

In order to determine the influence of age of onset, sex, onset symptoms, clinical course and interval from onset to first relapse on the subsequent outcome of multiple sclerosis (MS), data from 2934 cases of MS documented in a large population based study undertaken in Australia have been analysed. Disability on prevalence day (30 June 1981) was defined on the Kurtzke disability scale as mild (DSS 0-3), moderate (DSS 4-6) and severe (DSS 7-9). Prognostic factors associated with mild vs moderate/severe, and moderate vs severe disability on prevalence day were identified by logistic regression analysis. A worse prognosis was significantly associated with older age of onset, progressive disease course, onset symptoms that were multiple, pyramidal or cerebellar, and a short interval between onset and first relapse.

Prognostic factors for survival in multiple sclerosis

In a hospital-based study of 119 patients with definite multiple sclerosis, demographic and clinical factors were analysed with respect to their validity in assessing the long-term prognosis. Over a mean follow-up of 21.7 years, the following factors negatively influenced the prognosis by the univariate analysis: male sex, age at onset over 25, pyramidal involvement or spasticity at onset, > or =3 functional systems affected at onset or after 5 years, incomplete first remission, length of the first remission < or =1 year, >5 attacks in the first 10 years, secondary or primary-progressive disease, time to reach secondary progression over 5 years and time to reach EDSS 6 over 7 years. The multivariate model showed that in patients with relapsing-remitting disease, 5 years after onset, pyramidal involvement at onset and shorter time to reach EDSS 6 predicted poor outcome, while after 10 years, higher age at onset and incomplete first remission indicated poor prognosis. Ten years after onset, the predictors of poor outcome in the secondary-progressive group were shorter time to reach EDSS 6 or secondary progression and higher EDSS, while in the primary-progressive group those variables were spasticity or higher number of functional systems affected at onset, and higher EDSS after 5 and 10 years.

The search for virus in multiple sclerosis brain

Plaque-periplaque areas from MS brain tissue were explanted and propagated in tissue culture. The same in vitro techniques that successfully rescued measles virus from SSPE brain, papovavirus from PML brain, and HSV from normal human trigeminal ganglia, were applied. MS brain cells were also inoculated into chimpanzees, multiple rodent species, and embryonated hens eggs. No neurologic disease developed in experimentally infected animals, and no cytopathic effect was observed in explanted cells, or after cocultivation or fusion of MS brain cells with indicator cells. Further analysis of explanted and cocultivated cells by indirect immunofluorescence with various antiviral antisera prepared against viruses associated with post-infectious encephalomyelitis, as well as antisera to other ubiquitous viruses, failed to detect viral antigen. Finally, attempts to detect a latent enveloped virus in MS brain cells by 'superinfecting' MS brain cells in culture with vesicular stomatitis virus (VSV) did not reveal a VSV non-neutralizable fraction. Nevertheless, since oligoclonal bands (OGBs) in the CSF of patients with chronic infectious diseases of the CNS are directed against the causative agent, it is likely that OGBs in MS CSF are antibody directed against the agent or antigen that triggered disease. Although the relevant antibody may be scarce relative to irrelevant antibody in MS CSF, and only small amounts of an MS-specific antigen may be present in brain, this report provides a rationale for strategies proposed in our companion report by Owens et al which will allow detection of an MS-specific antigen or its cognate RNA in brain.

Disability and mortality in multiple sclerosis in western Norway

INTRODUCTION

Continued studies of frequency trends in carefully selected sites around the world can provide clues to the cause of multiple sclerosis (MS).

MATERIAL AND METHODS

Based on information from three different, semi-independent sources of information, we have examined the temporal trends in the average annual age-adjusted rates of disability pension incidence, mortality, and incidence of MS from 1966 to 1991 in Møre and Romsdal County, Norway.

RESULTS

The average annual age-adjusted disability pension incidence rates (1966-68 = 3.62/100,000; 1990-91 = 7.33/100,000), the mortality rates (1966-68 = 0.91/100,000; 1990-91 = 1.88/100,000), and the incidence rates (1966-68 = 4.22/100,000; 1990-91 = 5.02/100,000) all showed a statistically significant increase. The difference in the development of MS-specific disability pension prevalence rates in the county compared to the nation is notable.

CONCLUSIONS

We consider that the increase in disability pension incidence, mortality, and incidence of MS is of biological significance. Thus three different sources of information corroborate corresponding trends indicating that better case ascertainment and improved diagnostic facilities only partially can explain the reported MS increase in western Norway.

Impairment, disability, and handicap in multiple sclerosis. A cross-sectional study in an incident cohort in Møre and Romsdal County, Norway

We conducted a cross-sectional, geographically based study of functional status in an incident cohort of 124 multiple sclerosis (MS) patients with onset of disease from 1 January 1976 to 31 December 1986 in Møre and Romsdal County, Norway. The cohort comprised 58 men (46.8%) and 66 women (53.2%). One hundred and thirteen patients (91.1%) had a primary remitting course of disease and 11 (8.9%) had primary progressive MS. The mean age of onset was 33.3 years (range 14-64), and the mean duration of disease 7.8 years (range 1-23). The Minimal Record of Disability (MRD) of multiple sclerosis was applied to measure the degree of impairment, disability and handicap. The mean Kurtzke Expanded Disability Status Scale (EDSS) score was 3.76 (0-10), and the frequency distribution of the EDSS scores in the cohort was bimodal. Twenty-eight (22.6%) patients in the cohort had marked paraparesis, paraplegia of quadriplegia. Nineteen patients (15.3%) had frequent urinary incontinence, need for almost constant catheterization, or need for constant use of measures to evacuate stools. Five patients (4%) had a severe decrease in mentation or dementia. Forty-eight patients (38.7%) reported frequent problems with fatigue or fatigability preventing sustained physical function. Less than half of the cohort (42.7%) was working full-time, and 49.2% of the patients reported that they received external support to maintain their usual financial standard. Lack of ability to work full-time and accordingly the dependence upon external financial support were significantly associated with the primary progressive course of disease. Fatigue was statistically significantly related to lack of working ability. The estimated cost of MS in the county in 1991 was 48.2 million NOK (approximately 7.531.250 US $) based on the cost-of-illness methodology.

Prognostic factors for survival in multiple sclerosis: a longitudinal, population based study in Møre and Romsdal, Norway

A longitudinal, population based study of life expectancy in multiple sclerosis was performed in the county of Møre and Romsdal, Norway during the period 1950-84. A total of 251 patients with multiple sclerosis (110 men, 141 women, mean age at onset of disease 33.6 years) were included. The mean follow up time was 18.1 years. At the end of the study period 70 patients had died. Fifty four (77.1%) of these had multiple sclerosis as the underlying or contributing cause of death on the death certificates. Young age at onset, initial remitting clinical course, and the presence of sensory symptoms at onset were significantly associated with longer survival.

What is a chronic disease? The effects of a re-definition in HIV and AIDS

HIV disease has recently come to be defined as a chronic disease from both policy and clinical points of view. This paper investigates the meaning and some possible implications of the redefinition. The first section examines the features identifiable from medical texts used to define a disorder as either acute or chronic and explores some of the implications of the definition on patterns of care. In particular, different types of doctor-patient relationship are examined. The second section looks at the categorisation of HIV disease using these textbook definitions, finding that HIV is most appropriately labelled as chronic. The next section uses the clinical definitions to look at two conditions for comparison with HIV; testicular cancer and multiple sclerosis. In the fourth section the policy re-definition of HIV is investigated and one of the potential effects of a policy redefinition is discussed--a change in the extent to which services are centralised. The paper concludes that the policy and clinical communities confuse the picture of HIV disease as a chronic condition. There are strong parallels between care for people with HIV disease and care delivered for an acute condition. It therefore seems likely that the policy redefinition of the disease as chronic may not be entirely adequate to use as a current model for investigating or planning patterns of care in HIV disease.

On the pathogenesis of multiple sclerosis. A revised model of the cause(s) of multiple sclerosis, especially based on epidemiological data

Data from an epidemiological study are used to analyse the course of multiple sclerosis. It could be proved that the course of MS is not as haphazard as was often supposed. In general the course is described as being a chronic progressive one, in the majority of patients preceded by a relapsing-remitting period. In contrast to the relapsing-remitting phase the chronic progressive phase of the course does not show marks of being an autoimmune process. From recent data obtained by MRI and NMR spectroscopy it can be concluded that the chronic progression of handicaps in multiple sclerosis is related to neuronal and axonal damage. The relation between these different pathogenetic processes should be the aim of further research.

Natural history of multiple sclerosis

Multiple sclerosis (MS) is the most common idiopathic inflammatory disease of the central nervous system. The distinction between MS and other benign or fulminant inflammatory demyelinating disorders is based on quantitative, rather than qualitative, differences in chronicity and severity. Primary progressive MS may differ from relapsing-remitting MS in MRI lesion frequency, immunogenetic profile, responsiveness to immunosuppressive treatment, and histology. In 60% of patients, MS begins as a relapsing-remitting disease and evolves secondarily into a progressive neurological illness. Life expectancy is not substantially altered in patients with MS, particularly in the early years of the illness. The rate of suicide has been reported to be increased sevenfold in MS patients. Up to 40% of patients with attacks severe enough to render them nonambulatory may not recover. At 15 years from MS onset, 50% of patients are disabled to the point at which they at least require a cane to walk a half block. Early age at onset, female sex, relapsing-remitting course at onset, and perhaps optic neuritis or sensory symptoms at onset and relatively few attacks in the first two years are associated with a favorable course.

Prognostic criteria in an epidemiological group of patients with multiple sclerosis: an exploratory study

Demographic and clinical features and data on medical history and prior environmental exposure collected during an epidemiological long-term study of multiple sclerosis (MS) were tested for their possible prognostic value. Fifty-two benign MS patients were compared with 29 patients having a malignant course. A primary or secondary progressive course and cerebellar/lower brain-stem symptoms at onset indicated an unfavourable course, whereas no predictive value of sex or of any other type of onset symptomatology was found. Age at onset per se had no influence on prognosis but was associated with more rapid progression only by its relationship with a chronic progressive type of course. Prior illness, surgery, trauma and childhood exposure to defined environmental factors could not be identified as relevant for prognosis.