Prevalence and incidence of multiple sclerosis in Las Palmas, Canary Islands, Spain

Incidence and prevalence of multiple sclerosis in Spain: a systematic review

INTRODUCTION

Greater understanding of the prevalence and incidence of multiple sclerosis in Spain and their temporal trends is necessary to improve the allocation of healthcare resources and to study aetiological factors.

METHODS

We performed a systematic search of the MedLine database and reviewed the reference lists of the articles gathered. We collected studies reporting prevalence or incidence rates of multiple sclerosis in any geographical location in Spain, with no time limits. In 70% of cases, data were extracted by 2 researchers (FGL and EAC); any discrepancies were resolved by consensus.

RESULTS

We identified 51 prevalence and 33 incidence studies published between 1968 and 2018. In the adjusted analysis, the number of prevalent cases per 100 000 population increased by 26.6 (95% confidence interval [CI], 21.5-31.8) every 10 years. After adjusting for year and latitude, the number of incident cases per 100 000 population increased by 1.34 (95% CI, 0.98-1.69) every 10 years. We observed a trend toward higher prevalence and incidence rates at higher latitudes.

CONCLUSIONS

The prevalence of multiple sclerosis in Spain has increased in recent decades, although case ascertainment appears to be incomplete in many studies. Incidence rates have also increased, but this may be due to recent improvements in the detection of new cases.

Systematic literature review and meta-analysis of the prevalence of secondary progressive multiple sclerosis in the USA, Europe, Canada, Australia, and Brazil

Background

Secondary progressive multiple sclerosis (SPMS) is a subtype of multiple sclerosis (MS), which is a chronic neurological disease, characterised by inflammation of the central nervous system. Most of MS patients eventually progress to SPMS. This study estimates the prevalence of SPMS in the United States of America, Europe, Canada, Australia, and Brazil.

Methods

A systematic literature search of the Medline and Embase databases was performed using the OVID™ SP platform to identify MS epidemiological studies published in English from database inception to September 22, 2020. Studies reporting the prevalence of MS and proportion of SPMS patients in the included population were selected. The pooled prevalence of SPMS was calculated based on the proportion of SPMS patients. The Loney quality assessment checklist was used for quality grading. A meta-analysis of the proportions was conducted in RStudio.

Results

A total of 4754 articles were retrieved, and prevalence was calculated from 97 relevant studies. Overall, 86 medium- and high-quality studies were included in the meta-analysis. Most studies were conducted in European countries (84 studies). The estimated pooled prevalence of SPMS was 22.42 (99% confidence interval: 18.30, 26.95)/100,000. The prevalence of SPMS was more in the North European countries, highest in Sweden and lowest in Brazil. A decline in SPMS prevalence was observed since the availability of oral disease-modifying therapies. We also observed a regional variation of higher SPMS prevalence in urban areas compared with rural areas.

Conclusion

High variability was observed in the estimated SPMS prevalence, and the quality of the studies conducted. The influence of latitude and other factors known to affect overall MS prevalence did not fully explain the wide range of inter-country and intra-country variability identified in the results.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-022-02820-0.

Evaluation of Kappa Index as a Tool in the Diagnosis of Multiple Sclerosis: Implementation in Routine Screening Procedure

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system. Previous studies have shown that cerebrospinal fluid (CSF) kappa free light chains (K-FLCs) may have a role in MS diagnosis. In this regard, the kappa index (K-Index) has demonstrated higher sensitivity, and slightly lower specificity than oligoclonal bands (OCBs), the gold standard for the detection of intrathecal immunoglobulin synthesis, a feature of MS. Here, we evaluated the performance of the K-Index (K-Index = CSF/serum K-FLC divided by CSF/serum albumin) for the differential diagnosis of MS in a cohort of patients with suspected MS. K-FLCs were quantitatively measured in parallel serum and CSF samples by turbidimetry (Freelite Mx reagent on an Optilite system, The Binding Site Group Ltd). From 160 (63.4%) of a total of 252 patients who had K-FLC in CSF <0.03 mg/dl, below the sensitivity limit of the technique, only one had a diagnosis of MS. However, the absence of OCB in this same patient suggested no synthesis of intrathecal immunoglobulin. Globally, MS patients presented significantly higher K-Index levels than patients without an MS diagnosis (66.96 vs. 0.025, respectively; p < 0.0001). In agreement, patients with positive OCB testing also exhibited higher K-Index levels than patients negative for OCB (65.02 vs. 0.024, respectively; p < 0.0001). An optimal K-Index cutoff of 3.045 was defined by receiver operating characteristic (ROC) analysis for screening suspected MS, achieving a higher diagnostic sensitivity and slightly lower specificity than OCB (Sens. 0.9778 and Spec. 0.8629 vs. Sens. 0.8889 and Spec. 0.9086, respectively). A previously reported K-Index cutoff of 6.6 also showed good diagnostic performance (Sens. 0.9333; Spec. 0.8731), validating its power as a diagnostic biomarker for MS. Finally, a time- and cost-effective algorithm for MS screening is proposed that would offer an initial rapid evaluation of the intrathecal immunoglobulin synthesis through the K-FLC in CSF and K-Index analysis, followed by reflexing OCB testing that may be ordered more selectively.

Epidemiology of multiple sclerosis and vitamin D levels in Lanzarote, Canary Islands, Spain

Background

Low levels of 25-hydroxyvitamin D (25(OH)D) have been described as one of the possible environmental factors involved in multiple sclerosis (MS) etiopathogenesis.

Objectives

To study epidemiology of MS and 25(OH)D serum levels of patients in Lanzarote (29°02'06″N), a region with high ultraviolet radiation values during the whole year which is located far apart from Iberian Peninsula (36°-43°N), but without genetic/ethnic differences with it.

Methods

Incidence in Lanzarote was assessed according to McDonald 2005 criteria between January 2008 and December 2015 and prevalence date was 12/31/15. For 25(OH)D serum levels analyses, samples from 60 MS patients and 60 healthy donors (HD) were collected monthly in a one-year prospective study.

Results

The prevalence of MS in Lanzarote was 50.0/100,000 and the incidence per year was 2.5/100,000. Median 25(OH)D levels values were 29.1 ng/ml for MS patients (maximum = 36.1 ng/ml, minimum = 22.5 ng/ml) and 27.1 ng/ml for HD (maximum = 34.8 ng/ml, minimum = 22.8 ng/ml). There were no significant differences between 25(OH)D serum levels between MS patients and HD.

Conclusions

Lanzarote possesses lower prevalence and incidence values than peninsular Spain. Moreover, 25(OH)D serum levels do not differ between MS patients and HD.

Prevalence and mortality of patients with multiple sclerosis in France in 2012: a study based on French health insurance data

Data on the prevalence of multiple sclerosis (MS) in France are scarce. National and regional updated estimates are needed to better plan health policies. In this nationwide study, we provided estimates of the prevalence of MS in France in 2012 and mortality rate in 2013. MS cases were identified in the French national health insurance database (SNIIRAM-PMSI) using reimbursement data for disease-modifying treatment, long-term disease status for MS, disability pension for MS, and hospitalisation for MS (MS ICD-10 code: G35). We identified 99,123 MS cases, corresponding to an overall crude prevalence rate of 151.2 per 100,000 inhabitants [95% confidence interval (CI) 150.3-152.2]: 210.0 per 100,000 in women (95% CI 208.4-211.5) and 88.7 per 100,000 in men (95% CI 87.6-89.7). The overall prevalence rate was 155.6 per 100,000 inhabitants (95% CI 154.7-156.6) after standardization on the 2013-European population. We observed a prevalence gradient with a higher prevalence (190-200 per 100,000) in North-Eastern France and a lower prevalence in Southern and Western France (126-140). The crude mortality rate in 2013 was 13.7 per 1,000 MS cases (11.4 in women and 20.3 in men). The standardized mortality ratio was 2.56 (95% CI 2.41-2.72). Our results revise upwards the estimation of MS prevalence in France and confirm the excess mortality of MS patients compared to the general population.

Cognitive status in patients with multiple sclerosis in Lanzarote

OBJECTIVES

Cognitive impairment is a common feature in multiple sclerosis affecting ~43%-72% of patients, which involves cognitive functions such as memory, processing speed, attention, and executive function. The aim of this study was to describe the extent and pattern of the involvement of cognitive impairment and psychological status in all patients with multiple sclerosis on a small Spanish island.

PATIENTS AND METHODS

In all, 70 patients and 56 healthy controls were included in the study between February 2013 and May 2013. All participants were assessed using the Brief Repeatable Battery of Neuropsychological Test. The patients also completed instruments to evaluate the presence of fatigue, perceived cognitive dysfunction, and symptoms of anxiety and depression. All procedures were performed in a single session.

RESULTS

Cognitive impairment, defined as a score <1.5 standard deviation on two subtests of the battery, was present in 35% of the participants. The most frequently affected domain was working memory, followed by verbal memory and processing speed. Disease duration showed a moderate correlation with visuospatial memory and processing speed. The Expanded Disability Status Scale score correlated with verbal and processing speed. Verbal memory was correlated with depression symptoms and fatigue.

CONCLUSION

Cognitive impairment was present in 35% of the study population. The most affected domains were working memory and verbal memory. Working memory and verbal fluency deficit are independent factors of disease evolution. Cognitive decline is related to clinical variables and psychological measures such as fatigue or depression but not to anxiety.

Onset-adjusted incidence of multiple sclerosis in the Girona province (Spain): Evidence of increasing risk in the south of Europe

BACKGROUND

Recent studies show an increasing incidence of multiple sclerosis (MS) in southern Europe. Although by its geographical location and genetic characteristics Spain is expected to be similar to other southern European regions, data on incidence are scarce. The aim of this study was to determine the onset-adjusted incidence of MS in the Girona province in Catalonia (Spain).

METHODS

A prospective incidence study pooling data from the population-based Catalonia MS Registry was performed. Incident cases were defined as patients who had the onset of symptoms compatible with a clinically isolated syndrome (CIS) suggestive of MS in 2009 and fulfilled McDonald-2005 criteria during follow-up. Age- and sex-specific incidence rates were obtained.

RESULTS

The Registry included 182 patients residing in Girona that presented a CIS from January 2009 to December 2013. Fifty one patients had the onset of symptoms in 2009, of whom 27 patients fulfilled the diagnostic criteria, giving an incidence of 3.6 per 100,000 (CI 95% 2.4-5.3) inhabitants; 4.3 (CI 95% 2.5-7.1) for women and 2.9 (CI 95% 1.4-5.2) for men. The age-adjusted incidence rate for the European population was 3.29 (CI 95% 3.2-3.3).

CONCLUSION

The incidence estimation derived in this study is consistent with recent epidemiological data of MS in southern Europe suggesting an increase in incidence in this region.

Cost analysis of glatiramer acetate versus interferon-β for relapsing-remitting multiple sclerosis in patients with spasticity: the Escala study

OBJECTIVE

The Escala Study evidenced that the administration of glatiramer acetate for relapsing-remitting multiple sclerosis improved the spasticity of patients previously treated with interferon-β. However, whether such an improvement was translated into cost savings remained unclear. We therefore conducted a cost analysis of glatiramer acetate versus interferon-β in these patients with multiple sclerosis and spasticity.

METHODS

This cost analysis encompassed data from the observational Escala Study, which included patients with relapsing-remitting multiple sclerosis and spasticity whose treatment had been switched from interferon-β to glatiramer acetate. Costs prior to starting glatiramer acetate (interferon-β period) were compared to the subsequent six months on glatiramer acetate (glatiramer acetate period). The analysis was carried out following the recommendations for conducting pharmacoeconomic studies and from the Spanish National Health System perspective. Costs associated with multiple sclerosis treatment, spasticity treatment and relapse management were expressed in 2014 euros (€); a 7.5 % discount was applied-when needed-as stipulated in Spanish law.

RESULTS

The management of relapsing-remitting multiple sclerosis, spasticity and relapses accounted for a 6-month cost per patient of 7,078.02€ when using interferon-β and 4,671.31€ when using glatiramer acetate. Switching from interferon-β to glatiramer acetate therefore represented a cost saving of 2,406.72€ per patient in favour of glatiramer acetate, which resulted from savings in treatment costs, relapse management and spasticity treatment of 1,890.02€, 430.48€ and 86.21€, respectively. The ratio of the costs during interferon-β was 1.5 times the costs during glatiramer acetate; thus, a fixed budget of 5,000,000€ would enable 1,070 patients to be treated with glatiramer acetate and only 706 patients with interferon-β.

CONCLUSIONS

The treatment of relapsing-remitting multiple sclerosis with glatiramer acetate entailed cost savings when compared to interferon-β in patients with spasticity, which not only resulted from its lower costs of therapy and relapse management but also from its favourable effect on reducing spasticity. Thus, glatiramer acetate may be regarded as a more efficient alternative than interferon-β from the perspective of the Spanish National Health System.

Is it time for a new global classification of multiple sclerosis?

BACKGROUND

The geographic distribution of multiple sclerosis (MS) is classically divided into three zones based on frequency that were established by Kurtzke in the early 1970s. In recent years, an increasing number of epidemiological studies have shown significantly higher MS prevalence and incidence rates.

OBJECTIVE

The aim of this study was to review and update the geographic distribution of MS using incidence, prevalence and disease duration from the latest epidemiology surveys.

METHODS

We conducted a systematic review of articles on MS epidemiology published between January 1, 1990 and December 31, 2012.

RESULTS

MS studies were grouped by continent: the Americas, Europe, Asia, Australia/New Zealand, and Africa. A total of 101 studies were identified according to the inclusion criteria, and 58 reported incidence estimates. Globally, the median estimated incidence of MS was 5.2 (range: 0.5-20.6) per 100,000 p-yrs, the median estimated prevalence of MS was 112.0 (with a range of 5.2-335) per 100,000 p-yrs, and the average disease duration was 20.2 years (range: 7.6-36.2).

CONCLUSION

In the past few decades, the global prevalence and incidence patterns of MS have changed dramatically. Regardless of the reason of increasing prevalence and incidence rate, we suggest the need for a novel classification system based on global MS disease burden. Adopting such a system would improve economic efficiency and prioritization in health policy planning for MS.

Cost-effectiveness of glatiramer acetate and interferon beta-1a for relapsing-remitting multiple sclerosis, based on the CombiRx study

BACKGROUND

To assess the cost-effectiveness of the Disease Modifying Treatments (DMT), Glatiramer Acetate (GA) and Interferon beta-1a (IFN) in monotherapy alone and in combination for the prevention of relapses among Spanish patients aged between 18-60 years old with established Relapsing-Remitting Multiple Sclerosis (RRMS).

METHODS

A Markov model was developed to represent the transition of a cohort of patients over a 10 year period using the perspective of the Spanish National Health Service (NHS). The model considered five different health states with 1-year cycles including without relapse, patients with suspect, non-protocol defined and protocol defined exacerbations, as well as a category information lost. Efficacy data was obtained from the 3-year CombiRx Study. Costs were reported in 2013 Euros and a 3% discount rate was applied for health and benefits. Deterministic results were presented as the annual treatment cost for the number of relapses. A probabilistic sensitivity analysis was performed to test the robustness of the model.

RESULTS

Deterministic results showed that the expected annual cost per patient was lower when treated with GA (€13,843) compared with IFN (€15,589) and the combined treatment with IFN+GA (€21,539). The annual number of relapses were lower in the GA cohort with 3.81 vs 4.18 in the IFN cohort and 4.08 in the cohort treated with IFN+GA. Results from probabilistic sensitivity analysis showed that GA has a higher probability of being cost-effective than treatment with IFN or IFN+GA for threshold values from €28,000 onwards, independent of the maximum that the Spanish NHS is willing to pay for avoiding relapses.

CONCLUSION

GA was shown to be a cost-effective treatment option for the prevention of relapses in Spanish patients diagnosed with RRMS. When GA in monotherapy is compared with INF in monotherapy and IFN+GA combined, it may be concluded that the first is the dominant strategy.

Incidence and prevalence of multiple sclerosis in Europe: a systematic review

BACKGROUND

Multiple sclerosis (MS) is the most common cause of neurological disability in young adults worldwide and approximately half of those affected are in Europe. The assessment of differential incidence and prevalence across populations can reveal spatial, temporal and demographic patterns which are important for identifying genetic and environmental factors contributing to MS. However, study methodologies vary and the quality of the methods can influence the estimates. This study aimed to systematically review European studies of incidence and prevalence of MS and to provide a quantitative assessment of their methodological quality.

METHODS

A comprehensive literature search was performed to obtain all original population-based studies of MS incidence and prevalence in European populations conducted and published between January 1985 and January 2011. Only peer-reviewed full-text articles published in English or French were included. All abstracts were screened for eligibility and two trained reviewers abstracted the data and graded the quality of each study using a tool specifically designed for this study.

RESULTS

There were 123 studies that met the inclusion criteria. The study estimates were highly heterogeneous, even within regions or countries. Quality was generally higher in the more recent studies, which also tended to use current diagnostic criteria. Prevalence and incidence estimates tended to be higher in the more recent studies and were higher in the Nordic countries and in northern regions of the British Isles. With rare exceptions, prevalence and incidence estimates were higher in women with ratios as high as 3:1. Few studies examined ethnicity. Epidemiological data at the national level was uncommon and there were marked geographical disparities in available data, with large areas of Europe unrepresented and other regions well-represented in the literature. Only 37% of the studies provided standardized estimates.

CONCLUSIONS

Despite the breadth of the literature on the epidemiology of MS in Europe, inter-study comparisons are hampered by the lack of standardization. Further research should focus on regions not yet studied and the evaluation of ethnic differences in MS prevalence and incidence. National-level studies using current diagnostic criteria, validated case definitions and similar age- and sex-standardization would allow better geographical comparisons.

Geomagnetic disturbances may be environmental risk factor for multiple sclerosis: an ecological study of 111 locations in 24 countries

BACKGROUND

We noticed that a hypothesis based on the effect of geomagnetic disturbances (GMD) has the ability to explain special features of multiple sclerosis (MS). Areas around geomagnetic 60 degree latitude (GM60L) experience the greatest amount of GMD. The easiest way to evaluate our hypothesis was to test the association of MS prevalence (MSP) with angular distance to geomagnetic 60 degree latitude (AMAG60) and compare it with the known association of MS with geographical latitude (GL). We did the same with angular distance to geographic 60 degree latitude (AGRAPH60) as a control.

METHODS

English written papers with MSP keywords, done in Europe (EUR), North America (NA) or Australasia (AUS) were retrieved from the PubMed. Geomagnetic coordinates were determined for each location and AMAG60 was calculated as absolute value of numerical difference between its geomagnetic latitude from GM60L. By an ecological study with using meta-regression analyses, the relationship of MSP with GL, AMAG60 and AGRAPH60 were evaluated separately. MSP data were weighted by square root of number of prevalent cases. Models were compared by their adjusted R square (AR2) and standard error of estimate (SEE).

RESULTS

111 MSP data were entered in the study. In each continent, AMAG60 had the best correlation with MSP, the largest AR2 (0.47, 0.42 and 0.84 for EUR, NA and AUS, respectively) and the least SEE. Merging both hemispheres data, AMAG60 explained 56% of MSP variations with the least SEE (R = 0.75, AR2 = 0.56, SEE = 57), while GL explained 17% (R = 0.41, AR2 = 0.17, SEE = 78.5) and AGRAPH60 explained 12% of that variations with the highest SEE (R = 0.35, AR2 = 0.12, SEE = 80.5).

CONCLUSIONS

Our results confirmed that AMAG60 is the best describer of MSP variations and has the strongest association with MSP distribution. They clarified that the well-known latitudinal gradient of MSP may be actually a gradient related to GM60L. Moreover, the location of GM60L can elucidate why MSP has parabolic and linear gradient in the north and south hemisphere, respectively. This preliminary evaluation supported that GMD can be the mysterious environmental risk factor for MS. We believe that this hypothesis deserves to be considered for further validation studies.

National estimate of multiple sclerosis incidence in France (2001–2007)

Background:

In France, the incidence of multiple sclerosis (MS) is not well known, and MS is one of the 30 long-term illnesses for which patients are covered for 100% of their health care costs.

Objective:

To estimate the incidence of MS in France and its geographic variations.

Methods:

We estimated the national rate for notification of MS to the main French health insurance system, and its confidence interval (CI), between November 2000 and October 2007, which covers 87% of the population. We analysed geographic variations using a Bayesian approach.

Results:

Between November 2000 and October 2007, among a covered population of 52,449,871, some 28,682 individuals were registered as having MS. After age standardization according to the European population, the notification rate for MS was 6.8 per 100,000 (6.7–6.9), 9.8 (9.7–10.0) in women and 3.7 (3.6–3.8) in men. When the under-notification rate (11.5% and 29%) was taken into account, the notification rate per 100,000 inhabitants was estimated between 7.6 and 8.8. The notification rate was higher in north-eastern France, and lower on the Atlantic coast and in the Alps as well as on both sides of the Rhône River.

Conclusions:

This study, conducted on a representative French population, provides for the first time national estimates of MS incidence between November 2000 and October 2007.

Cost-effectiveness analysis of disease modifiying drugs (interferons and glatiramer acetate) as first line treatments in remitting-relapsing multiple sclerosis patients

Abstract Objective: The aim of this study was to assess cost-effectiveness of the different Disease Modifying Drugs (DMD) used as first-line treatments (interferons IM IFNβ-1a, SC IFNβ-1a, SC IFNβ-1b, and glatiramer acetate, GA) in Remitting-Relapsing Multiple Sclerosis (RRMS) in Spain.

METHODS

A Markov model was developed to simulate the progression of a cohort of patients with RRMS, during a period of 10 years. Seven health states, defined by the Expanded Disability Status Scale (EDSS), were considered in the model. Patients with an EDSS score less than 6.0 were assumed to be treated with one of the DMD. In addition, all patients were assumed to receive symptomatic treatment. The monthly transition probabilities of the model were obtained from the literature. The analysis was performed from the societal perspective, in which both direct and indirect (losses in productivity) healthcare costs (€, 2010) were included. A discount rate of 3% was applied to both costs and efficacy results.

RESULTS

GA was the less costly strategy (€322,510), followed by IM IFNβ-1a (€329,595), SC IFNβ-1b (€ 333,925), and SC IFNβ-1a (€348,208). IM IFNβ-1a has shown the best efficacy results, with 4.176 quality-adjusted life years (QALY), followed by SC IFNβ-1a (4.158 QALY), SC IFNβ-1b (4.157 QALY), and GA (4.117 QALY). Incremental costs per QALY gained with IM IFNβ-1a were €-1,005,194/QALY, €-223,397/QALY, and €117,914/QALY in comparison to SC IFNβ-1a, SC IFNβ-1b, and GA, respectively.

CONCLUSIONS

First-line treatment with GA is the less costly strategy for the treatment of patients with RRMS. Treatment with IM IFNβ-1a is a dominant strategy (lower cost and higher QALY) compared with SC IFNβ-1a and SC IFNβ-1b. However, IM IFNβ-1a is not a cost-effective strategy vs GA, because incremental cost per QALY gained with IM IFNβ-1a exceeds the €30,000 per QALY threshold commonly used in Spain.

LIMITATIONS

The highly-restrictive inclusion criteria of clinical trials limits generalization of the results on efficacy to all patients with multiple sclerosis. Availability of data for head-to-head comparisons is associated with the use of information from clinical trials.

Multiple sclerosis prevalence in Malaga, Southern Spain estimated by the capture–recapture method

Background: Although not definitively proven, there is commonly accepted to be a latitudinal gradient in the distribution of multiple sclerosis (MS), which is more frequent in temperate zones. The European Mediterranean countries are situated in a zone of median frequency, although ever increasing figures have been noted in the last decades.

Objective: The objective of this study was to assess the current prevalence rate of MS in the province of Malaga, Southern Spain.

Methods: The capture–recapture method (CRM) uses independent sources of data and permits the number of non-registered cases of a given disease to be estimated, and by doing so, to avoid ascertainment bias.

Results: Use of this method showed the estimated prevalence rate of MS in the province of Malaga, Southern Spain, to be 125/105 (95% confidence interval: 102/105–169/105), higher than the figures published previously.

Conclusions: Although we recognize that these data need to be confirmed in further studies and in other areas of the country using a similar method, we believe this study is the first to find such high figure of prevalence, being very similar to the figures reported in recent years in other southern European countries.

Increasing frequency of multiple sclerosis in Catania, Sicily: a 30-year survey

Background and Objective: The objective of this study was to determine the prevalence and incidence of multiple sclerosis (MS) and its temporal profiles from 1975 to 2005 in the city of Catania.

Methods: The incidence of MS from 1975 to 31 December 1999 had been previously investigated by the same group. The frequency of MS in the community of Catania from 1 January 2000 to 31 December 2004 was studied in a population of 313,110 inhabitants (2001 census). All patients who satisfied Poser’s criteria were considered as prevalent and incident cases.

Results: Three hundred and ninety-eight patients with MS who had experienced the clinical onset of the disease before 31 December 2004 were found in a population of 313,110 inhabitants. The prevalence rate was 127.1/100,000 [95% confidence interval (CI) 115.1–140.4]. From 2000 to 2004, 108 patients with MS had clinical onset of the disease . The mean annual incidence was 7.0/100,000 (95% CI 5.7–13.7) and was higher in women (8.4/100,000; 95% CI 6.4–10.5) than in men (5.3/100,000; 95% CI 3.7–7.2). The mean length of time between the date of clinical onset and the date of the diagnosis was 1.4 ± 1.7 years. During the last 30 years the incidence of MS in this population increased from 1.3/100,000 during the first quinquennium (1975–9) to 7.0/100,000 during 2000–4.

Conclusions: Incidence rates have further increased in this population, suggesting that the risk of MS is still increasing.

Epidemiology of multiple sclerosis in Europe: a review

Multiple sclerosis (MS) is a progressive demyelinating and degenerative disease of the CNS with symptoms dependent on the type of the disease and the site of lesions. During the progression of the disease, symptoms become more permanent and progressive disability ensues. MS is a disease characterized by wide variations between patients, thus making categorization difficult. The aim of the current study was to review the existing epidemiological data of MS in Europe published during the last decade (2000-2009), using PubMed. Findings revealed an increasing incidence of MS during the last decade. Recent data indicate that latitude does not play a key role in determining the onset of the disease. MS has a significant impact on the quality of life for most patients over many years. The disease is twice as common in women than in men, and is at its peak in the most economically productive years of life. Pregnancy, postpartum status and vaccines may influence the onset and the course of the disease. Only one of the reviewed papers provides a view of progression from onset to death.

The changing demographic pattern of multiple sclerosis epidemiology

The uneven distribution of multiple sclerosis (MS) across populations can be attributed to differences in genes and the environment and their interaction. Prevalence and incidence surveys could be affected by inaccuracy of diagnosis and ascertainment, and prevalence also depends on survival. These sources of error might play a part in the geographical and temporal variations. Our literature search and meta-regression analyses indicated an almost universal increase in prevalence and incidence of MS over time; they challenge the well accepted theory of a latitudinal gradient of incidence of MS in Europe and North America, while this gradient is still apparent for Australia and New Zealand; and suggest a general, although not ubiquitous, increase in incidence of MS in females. The latter observation should prompt epidemiological studies to focus on changes in lifestyle in females. New insights into gene-environment and gene-gene interactions complicate interpretations of demographic epidemiology and have made obsolete the idea of simple causative associations between genes or the environment and MS.

Temporal trends in the incidence of multiple sclerosis: a systematic review

BACKGROUND

Multiple sclerosis (MS) has been traditionally considered to be more frequent in women and in regions more distant from the equator. However, recent reports suggest that the latitude gradient could be disappearing and that the female-to-male ratio among patients with MS has increased in the last decades. We have conducted a systematic review of incidence studies of MS to assess the overall incidence of MS and explore possible changes in the latitude gradient and the female-to-male ratio over time.

METHODS

Systematic review of incidence studies of MS published in Medline between 1966 and February 2007. Age- and sex-specific incidence rates were collected from eligible publications. We computed age-adjusted rates using the world population as standard, and assessed differences in rates according to latitude and period of case ascertainment. Additionally, we evaluated the association between period of case ascertainment and the female-to-male ratio.

RESULTS

The overall incidence rate of MS was 3.6 cases per 100,000 person-years (95% CI 3.0, 4.2) in women and 2.0 (95% CI 1.5, 2.4) in men. Higher latitude was associated with higher MS incidence, though this latitude gradient was attenuated after 1980, apparently due to increased incidence of MS in lower latitudes. The female-to-male ratio in MS incidence increased over time, from an estimated 1.4 in 1955 to 2.3 in 2000.

CONCLUSION

The latitude gradient present in older incidence studies of multiple sclerosis (MS) is decreasing. The female-to-male MS ratio has increased in the last five decades.

Prevalence and incidence of multiple sclerosis in western Greece: a 23-year survey

BACKGROUND

The frequency of multiple sclerosis (MS) in Greece remains speculative, as data from many parts are still lacking.

OBJECTIVE

To estimate trends in MS prevalence and annual incidence in western Greece from January 1, 1984 to December 31, 2006.

METHODS

Patients were identified from the patient records of the Department of Neurology at Patras University Hospital in Rion-Patras. Only patients with a definite MS diagnosis according to Poser's criteria and retrospective application of the McDonald's criteria were included. We calculated age- and sex-specific prevalence rates for patients living in the study area on December 31, 2006. Annual incidence rates were calculated for the period 1984-2006.

RESULTS

The crude prevalence rate of definite MS cases increased significantly in 23 years from 10.1/100,000 recorded in northeastern Greece in 1984 to 119.61/100,000 on December 31, 2006 in western Greece for the 780 cases still alive. The mean annual incidence rate increased from 2.71/100,000 recorded during the period 1984-1989 to 10.73/100,000 in the 5-year period of 2002-2006.

CONCLUSION

The prevalence rates were higher than expected, but closer than in previous surveys conducted in Greece to those reported recently in Sicily and Istanbul. These findings place the area in the high-risk zone.

Multiple Sclerosis in Isfahan, Iran

BACKGROUND

This survey was planned to study the prevalence and incidence of multiple sclerosis (MS) in Isfahan, Iran and to describe the clinical features of MS in general and in specific subgroups of patients (early-onset, late-onset, familial, and conjugal cases) and to compare our results with other reports.

METHODS

A cross-sectional study was conducted from April 5, 2003 to July 31, 2006. All patients known to have definite MS according to McDonald's criteria, alive, resident within Isfahan (a large province of Iran) and members of Isfahan MS Society (IMSS) were included in the study. Demographic and case-related information were recorded. A total number of 1718 definite MS patients (388 men and 1330 women) were identified from IMSS database.

RESULTS

The overall period prevalence of MS was 43.8/100,000. Among men the prevalence was 19.2 (95% CI: 17.4-21.2)/100,000 and among women 69.6 (95% CI: 66-73.4)/100,000. A female preponderance of 3.4 existed among these patients. In the year 2005, 143 new cases were diagnosed, resulting in an incidence rate of 3.64/100,000. The mean age of onset was 25.36 +/- 8.6 years (range 5-63 year), and mean duration of disease was 7.1 (+/-5.2) years for men and 6.7 (+/-5) years for women. Sensory and visual disturbances were the most common initial presentations with a prevalence of 51.7% and 47.5%, respectively. Cases identified include: early-onset MS (less than 15 years old at onset) with 87 cases (5%), late-onset MS (over 50 years old at onset) with 20 cases (1.1%), familial MS with 209 cases (12.2%), and conjugal MS with 6 cases (0.5%).

CONCLUSION

Isfahan is a medium- to high-risk area for MS, with prevalence higher than what has previously been reported, possibly because of an increase in the incidence rate. Clinical and demographic characteristics were similar to other reports; however, some differences existed.

Costs and quality of life of multiple sclerosis in Spain

This cost-of-illness analysis is based on information from 1.848 patients in Spain and is part of a Europe-wide study on the costs of multiple sclerosis. The objective was to analyze the costs and quality of life (QOL) related to the level of disease severity and progression. Patients were identified by the Asociación Española de Esclerosis Múltiple (AEDEM) and participated in the survey by answering a mail questionnaire (response rate 31.8%). In addition to details on the disease (type of disease, relapses, level of functional disability), the questionnaire asked for information on all resource consumption, medical, non-medical, work absence and informal care, as well as utility (QOL). The mean age of the cohort was 45 years, and only 5.5% of patients were 65 years of age or more. Approximately 36% of patients had mild disease (Expanded Disability Status Scale [EDSS] score of 0-3), 44.8% had moderate disease (EDSS score of 4-6.5) and 17.7% had severe disease (EDSS score > or =7). The mean EDSS score in the sample was 4.5 (median 5.0), with a utility of 0.554. Costs and utility are highly correlated with disease severity. Workforce participation decreases from around 70% in early disease to less than 5% in the very late stages. Hospitalization is very infrequent in early disease, representing less than euro 1.300 per patient per year for patients at EDSS scores <6, but increases steeply for patients at scores > or =7. Ambulatory care increases fivefold between early and late disease, while investments and services increase from basically no cost to just over euro 6.000 at EDSS scores > or =7. Productivity losses increase more than eightfold, and informal care increases from euro 593 at EDSS scores of 0-1 to nearly euro 34.228 at scores of 8-9. Hence, total mean costs per patient are driven by the distribution of the severity levels in the sample, increasing from euro 10.425 at EDSS scores of 0-1 to euro 45.264 at a score of 7, and euro 65.693 at scores of 8-9. The same is true for utility, which decreases from 0.865 to 0.084 as patients progress from the mildest to the most severe disability levels. However, the utility loss compared to the age- and gender-matched general population is high at all levels of the disease ( approximately 0.25 in patients below 30 years of age with an EDSS score of 2-3, and approximately 0.4 in patients over 60 years of age and a score of > or =6), leading to an estimated annual loss of 0.276 quality-adjusted life-year per patient. Relapses for patients with an EDSS score below 5 are associated with a cost of approximately euro 2.750 and a utility loss of 0.1 during the quarter in which they occur.