A systematic review of the epidemiology of status epilepticus

Population-based data on the incidence, aetiology, and mortality associated with status epilepticus (SE) are required to develop preventative strategies for SE. Through a systematic review, we aimed to assess the methodological quality as well as similarities, and differences between available population based studies in order to arrive at conclusions on the epidemiology of SE. All population-based studies where primary outcome was incidence, aetiology or mortality of SE were identified through a systematic search and synthesized. Methodological quality of studies were independently rated by two examiners using a unique scoring system. Seven population-based projects on SE yielding nine published reports and five abstracts were reviewed. Quality scores were in the range of 19-34 with a possible maximum of 40 (kappa scores 0.67-1.0). The incidence of SE has a bimodal distribution with peaks in children aged less than a year and the elderly. Most SE were acute symptomatic. Short-term mortality was 7.6-22% and long-term mortality was 43%. Age and aetiology were the major determinants of mortality. There are few population-based studies on SE but most are of good quality. Most studies are primarily or exclusively based on adult populations. There is limited information on the association of ethnicity and socio-economic status and SE.     

HLA-DRB1 and multiple sclerosis in Argentina

Background:  The association of multiple sclerosis (MS) with HLA DR subtypes, and particularly human leukocyte antigen (HLA)-DRB1*15 has been a consistent finding across nearly all Caucasian MS populations. In South America, scarce data exist about this issue. As the complete characterization of the HLA association range around the world is important to understand the role of this locus in MS susceptibility, we analyzed the frequency of HLA-DRB1* allelic groups in an MS population in Argentina.
Methods:  HLA-DRB1 locus was genotyped using PCR and sequence-specific primer amplification in 61 MS patients born in Buenos Aires, Argentina and 1216 healthy controls. Allele frequencies were compared between groups.
Results:  The HLA-DRB1*15 allele frequency significantly differed between controls and patients (13.5% and 33.9% respectively, P  < 0.001, OR 2.51, 95% CI: 1.7–3.0). The other allele frequencies did not show significant differences between patients and controls.
Conclusions:  The present HLA class II population study is in accordance with other Caucasian MS surveys which have found that HLA-DRB1*15 allele is strongly associated with MS disease. In Argentina, this is the first study performed to analyze the association of HLA-DRB1*15 and MS susceptibility in a Caucasian population and therefore contributes with new data to the immunogenomic global MS map.     

Incidence of multiple sclerosis in Buenos Aires: a 16‐year health maintenance organization‐based study

Objective: The present study was undertaken to determine the incidence of MS in a health maintenance organization from Buenos Aires, the largest populated area in Argentina. Methods: Population was all members of a hospital‐based health maintenance organization who were affiliated since January 1992 up to December 2007. Each person was followed contributing time at risk since January 1992 or enrollment date to the final date. Patients with definite diagnosis according to Poser’s criteria were included. Incidence density was calculated with 95% confidence intervals. Results: A total of 145 000 patients were followed for a total of 1 021 515 person‐years, of whom 18 developed the disease. Incidence density (ID): 1.76 /100 000 person‐years (95% CI: 1.1–2.8/100 000 person‐years). Conclusion: The incidence density of 1.76 per 100 000 suggests a low‐median risk area for MS. This study constitutes the first of its kind to cover data of MS incidence in Argentina.     

Changes in multiple sclerosis epidemiology in Finland over five decades

Finland is a high-risk region for multiple sclerosis (MS) with several epidemiological studies on the subject published since 1964, but these have not been comprehensively scrutinized. The objective of this study was to review previous studies of Finnish MS epidemiology, introduce new data on MS prevalence in western parts of Finland and do further analyses on data from previous studies. We performed a systematic search on articles regarding MS epidemiology in Finland in PubMed database, and all relevant articles were included in this review. MS prevalences in the western hospital districts of Vaasa, South Ostrobothnia and Pirkanmaa were calculated in 1980-2007 by using previously unpublished data obtained from a retrospective search from hospital administrative registries. To enhance comparability of the epidemiological figures, we calculated age-standardized prevalence of MS from the new data from western hospital districts and previous data from North Ostrobothnia, Southwest Finland and North Karelia. Marked regional differences in MS epidemiology were confirmed with concentration of the disease in the western and south-western parts of the country. The highest regional age-standardized MS prevalence of 288/100 000 was reported in South Ostrobothnia in 2007. A clear and stable increase in MS prevalence was observed through the decades, but the only marked increase in incidence happened in 1990s. Methodological differences hampered direct comparisons of different studies, highlighting the importance of common principles of reporting and standardizing the epidemiological figures. More comprehensive studies on MS epidemiology are still warranted to yield important information concerning the aetiology of the disease.     

Prevalence of multiple sclerosis in Buenos Aires, Argentina using the capture-recapture method

Background:  Scarce data exist about multiple sclerosis (MS) prevalence in South America. The objective of the study is to determine the prevalence of MS in a high populated area from Argentina (Greater Buenos Aires Metropolitan area) using the capture-recapture methodology.
Methods:  Greater Buenos Aires is the generic denomination that refers to the megalopolis comprised by the autonomous city of Buenos Aires and the surrounding conurbation of the province of Buenos Aires. The study was carried out taking July 1996 as the prevalence month. We used capture-recapture method to estimate the prevalence of MS cross matching registries from four MS Centers.
Results:  A total of 803 registries were obtained from the four lists. Log-linear model for capture-recapture method was used to analyze the data. The population of the area based on the 1990 census was 12 594 974; the number of MS cases estimated amongst sources interactions were between 1833 and 2359; the prevalence estimated ranged from 14 to 19.8 cases per 100 000 inhabitants.
Conclusions:  This is the first study to provide epidemiological data on the prevalence of MS in a large population in Argentina (Greater Buenos Aires Metropolitan area). Further epidemiological studies will clarify the true prevalence of MS in South America.     

Accuracy of diagnostic tests in multiple sclerosis--a systematic review

New diagnostic criteria for multiple sclerosis (MS) have been recently proposed and further updates are upcoming. This systematic literature review summarizes diagnostic studies in suspected MS to clarify the value of diagnostic tests. We included studies of at least 40 patients followed up for 2 years. All studies are limited by the fact that no gold standard to validate diagnostic tests is available. A second relapse is used as a surrogate in relapsing-remitting MS, but long follow-up of at least 5 years is necessary to detect all cases. Many studies showed selection bias, partly because of the vague definition of a clinically isolated syndrome. Based on these limitations, sensitivity of magnetic resonance imaging (MRI) criteria was between 35% and 100%, and specificity was between 36% and 92%. Cerebrospinal fluid (CSF) oligoclonal banding showed sensitivities between 69% and 91% with specificities between 59% and 94%. Combination studies of MRI and CSF indicate enhanced sensitivity (56-100%) and specificity (53-96%). Studies on evoked potentials did not justify conclusions about their value. A combination of simplified MRI criteria with CSF might be the best approach for an early MS diagnosis. However, the value of a very early diagnosis stays questionable as patients' benefit of new diagnostic criteria has never been addressed.     

The epidemiology of multiple sclerosis in Europe

Multiple sclerosis (MS) is a chronic and potentially highly disabling disorder with considerable social impact and economic consequences. It is the major cause of non-traumatic disability in young adults. The social costs associated with MS are high because of its long duration, the early loss of productivity, the need for assistance in activities of daily living and the use of immunomodulatory treatments and multidisciplinary health care. Available MS epidemiological estimates are aimed at providing a measure of the disease burden in Europe. The total estimated prevalence rate of MS for the past three decades is 83 per 100 000 with higher rates in northern countries and a female:male ratio around 2.0. Prevalence rates are higher for women for all countries considered. The highest prevalence rates have been estimated for the age group 35–64 years for both sexes and for all countries. The estimated European mean annual MS incidence rate is 4.3 cases per 100 000. The mean distribution by disease course and by disability is also reported. Despite the wealth of epidemiological data on MS, comparing epidemiological indices among European countries is a hard task and often leads only to approximate estimates. This represents a major methodological concern when evaluating the MS burden in Europe and when implementing specific cost-of-illness studies.     

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.     

Everyday memory measures in multiple sclerosis: a systematic review

ABSTRACT

Everyday memory is one of the most affected cognitive functions in multiple sclerosis (MS). Assessing everyday memory problems is crucial for monitoring the impact of memory deficits on individuals’ day-to-day lives and evaluating the effectiveness of interventions that aim to improve cognitive functions. The aim of this systematic review was to identify the research literature on everyday memory measures used with people with MS, describe the types of measures used, and summarise their psychometric properties. Empirical studies of cognitive function in MS using standardised everyday memory measures were included. Online databases (MEDLINE, PsycINFO, PsycARTICLES, Embase) and Google Scholar were searched. Forty-four studies met the inclusion criteria. A total of 12 measures were identified, with varied uses and administration methods. The majority of papers did not report any psychometric properties for MS populations. The few papers that did, reported that the measures have good reliability and appear to have good face, concurrent, and ecological validity, but these need to be evaluated further. This review presents researchers and clinicians with an overview of the various everyday memory measures used in studies with people with MS, to help them choose the appropriate measure for their evaluations.     

Effect of birthplace on the development of amyotrophic lateral sclerosis and multiple sclerosis

After World War II the southeastern part of Finland was ceded to the Soviet Union and its entire population evacuated to other areas of the country. The prevalences of amyotrophic lateral sclerosis (ALS) and multiple sclerosis (MS) were studied among the evacuees and compared to the corresponding data among the nonevacuated population. The prevalence of ALS among the war evacuees was two times higher than among the nonevacuated population (18.0 and 8.8 per 100,000, respectively). The prevalence of MS among the evacuees was only half of that found among the nonevacuated population, 38.3 and 73.0 per 100,000, respectively. The findings for ALS indicate that birthplace may have an effect on the later development of the disease and that there may have existed some environmental factor(s) which have made the evacuees more liable to contract the disease later in their lives. The low figure of MS for evacuees supports our previous results of an uneven geographic distribution of MS in Finland with the high-risk areas in the western and southwestern parts of the country. No accumulation of MS was found among the evacuees living in the high-risk areas.     

Western and Asian features of multiple sclerosis in Mexican Mestizos

OBJECTIVES: The objective of this study was to compare the clinical expression of MS in Mexican Mestizos with that of patients of European or Asian descent; as well as to compare the annual frequency of new cases with that observed in the previous decades. PATIENTS AND METHODS: All patients with diagnosis of definite MS seen at the National Institute of Neurology and Neurosurgery of Mexico from January 1993 to December 2003 were studied (n=312). Sociodemographic and clinical characteristics were compared with reports of patients from either Western or Asian origin; the long-term disability score was analyzed according to gender, age of onset of MS and the initial symptom. RESULTS: The clinical expression of MS in Mexican Mestizos shares some characteristics with both, Asian and Western forms of MS indicating that the genetic composition of Mexican Mestizos participates in the clinical expression of the disease. Also, at the prevalence date, the mean age of patients and the duration of the disease were lower in our patients than in MS patients from endemic countries suggesting a true increasing incidence in recent times, rather than only improved case ascertainment. CONCLUSIONS: Clinical expression of MS in Mexican Mestizos shows the coexistence of some features common in European and in Asian cases.     

A numerical scoring system for the classification of multiple sclerosis

A simple, numerical system for the classification of multiple sclerosis into probable and definite categories is proposed. This system is based upon the analysis of the clinical symptomatology of 111 autopsy-proved cases of the disease from England, Norway and the United States. It is not designed to be used as an aid in the diagnosis and should be applied only to those cases where multiple sclerosis is suspected. It permits the incorporation of data obtained by means of evoked responses studies, psychological evaluations and other methods for confirming anamnestic information or delineating some asymptomatic lesions. The numerical system also provides a means for plotting the temporal evolution of the disease strictly in terms of the appearance of new signs and symptoms since recurrences of previously experienced symptoms cannot be scored; thus it has the advantage of not allowing so-called exacerbation due to physiological or psychological factors to falsely suggest disease progression or activity. The major use of this scoring system is to provide a reasonably reliable means of comparing epidemiologic data from different investigators by more clearly defining the probable and definite categories.     

Prevalence and clinical features of multiple sclerosis in Latin America

Multiple sclerosis (MS) in Latin America (LA) is considered to have a low to medium prevalence. However, accurate information on MS in LA is scarce. The aim of this study was to compare clinical characteristics among LA patients through a systematic review of the literature. A systematic search (Spanish, Portuguese and English) was done for all clinical studies of MS in humans (MEDLINE, PubMed, Scielo, BIREME, EMBASE and LILACS) up to May 2011 being focused on a well-defined Latin American population (peer-reviewed journal) following the MOOSE guidelines. The search strategy included combinations of different Mesh terms (two independent researchers). Classification of each article by using the Oxford Centre for Evidence-based Medicine – Levels of Evidence was done. The total number of patients per country for each specific characteristic was compiled. Chi-square test was used to compare the characteristics in the studies retrieved per country. There were 38 articles fulfilling the inclusion criteria, accounting for 4524 patients. Relapsing-remitting form was the most frequent in LA patients and the main initial symptom was motor, followed by optic neuritis and sensorial. A mild expanded disability status scale was the most prevalent in all LA countries. Factors accounting for differences in distribution and clinical course across LA countries include genetics, environment, diagnostic techniques, socioeconomic structure and medical facilities.     

An epidemiological study of multiple sclerosis in central Sardinia, Italy

Objectives – To verify morbidity estimates in central Sardinia, Italy. Methods – A prevalence study was performed in the province of Nuoro, Central Sardinia, which has a population of 273,768 inhabitants (135,383 men and 138,385 women). A complete enumeration approach was adopted by using all possible case-collection sources. Results – On prevalence day, December 31, 1993, 394 subjects (124 men and 270 women) living in the study area were known to suffer from definite and probable MS, giving a crude prevalence rate of 143.9 cases per 100,000 people, 91.6 for males and 195.11 for females. The crude prevalence estimated on December 31, 1985, based on 282 MS cases alive in the study area, was 102.94 per 100,000. Conclusion – This study reinforced central Sardinia's position as a high and rising prevalence area for MS.     

Epidemiology of multiple sclerosis in Bulgaria

An epidemiological study of MS in 5 districts of Bulgaria was carried out over period of 10 years to establish MS prevalence, incidence and mortality. The district of Sofia was the highest, indicating increased prevalence among the urban population, and more female than male cases. In the age group up to 15 years, age at onset was significantly earlier in the urban than in the rural cases.