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.

Epidemiology of listeriosis in a region in central Italy from 2010 to 2019: Estimating the real incidence and space-time analysis for detecting cluster of cases

BACKGROUND

Contamination and transmission of different Listeria monocytogenes strains along food chain are a serious threat to public health and food safety. Understanding the distribution of diseases in time and space-time is fundamental in the epidemiological study and in preventive medicine programs. The aim of this study is to estimate listeriosis incidence along 10-years period and to perform space-time cluster analysis of listeriosis cases in Marche Region, Italy.

METHODS

The number of observed listeriosis cases/year was derived from regional data of surveillance of notifiable diseases and hospital discharge form. The capture and recapture method (C-R method) was applied to estimate the real incidence of listeriosis cases in Marche Region and the space-time scan statistics analysis was performed to detect clusters of space-time of listeriosis cases and add precision to the conventional epidemiological analysis.

RESULTS

The C-R method estimation of listeriosis cases was 119 in the 10- year period (2010-2019), with an average of 31.93 % of unobserved cases (lost cases). The estimated mean annual incidence of listeriosis was 0.77 per 100,000 inhabitants (95 %CI 0.65-0.92), accounting for 6.07 % of additional listeriosis cases per year than observed cases. Using the scan statistic, the two most likely clusters were identified, one of these was statistically significant (p < 0.05). The underdiagnosis and under-reporting in addition to listeriosis incidence variability suggested that the surveillance system of Marche Region should be improved.

CONCLUSIONS

This study provides evidence of the ability of space-time cluster analysis to complement traditional surveillance of food-borne diseases and to understand the local risk factors by implementing timely targeted interventions.

Consensus for the Early Identification of Secondary Progressive Multiple Sclerosis in Portugal: a Delphi Panel

INTRODUCTION

Multiple sclerosis is a disease with a heterogeneous evolution. The early identification of secondary progressive multiple sclerosis is a clinical challenge, which would benefit from the definition of biomarkers and diagnostic tools applicable in the transition phase from relapsing-remitting multiple sclerosis to secondary progressive multiple sclerosis. We aimed to reach a Portuguese national consensus on the monitoring of patients with multiple sclerosis and on the more relevant clinical variables for the early identification of its progression.

MATERIAL AND METHODS

A Delphi panel which included eleven Portuguese Neurologists participated in two rounds of questions between July and August of 2021. In the first round, 39 questions which belonged to the functional, cognitive, imaging, biomarkers and additional evaluations were included. Questions for which no consensus was obtained in the first round (less than 80% of agreement), were appraised by the panel during the second round.

RESULTS

The response rate was 100% in both rounds and consensus was reached for a total of 33 questions (84.6%). Consensus was reached for monitoring time, evaluation scales and clinical variables such as the degree of brain atrophy and mobility reduction, changes suggestive of secondary progressive multiple sclerosis. Additionally, digital devices were considered tools with potential to identify disease progression. Most questions for which no consensus was obtained referred to the cognitive assessment and the remaining referred to both functional and imaging domains.

CONCLUSION

Consensus was obtained for the determination of the monitorization interval and for most of the clinical variables. Most questions that did not reach consensus were related with the confirmation of progression taking into account only one test/domain, reinforcing the multifactorial nature of multiple sclerosis.

TyPed study: Natalizumab for the treatment of pediatric-onset multiple sclerosis in Portugal

BACKGROUND

A significant proportion of pediatric-onset multiple sclerosis (POMS) patients do not respond to first-line disease-modifying therapies. Clinical trials showed that natalizumab is effective and safe in adults, but there are limited clinical trial data for children. Natalizumab is currently prescribed off-label for POMS. We aimed to characterize the effectiveness, safety and tolerability of natalizumab in all POMS cases treated in Portugal (from 2007 to 2018).

METHODS

Data from clinical records were retrospectively collected for all POMS cases treated with natalizumab in Portugal.

RESULTS

Twenty-one patients were included, 14 (67%) of which were female. The median age at POMS diagnosis was 13 years old. The median duration of treatment with natalizumab was 2 years and 3 months. Median Expanded Disability Status Scale score decreased from 1.5 to 1.0 after 24 months. The Annualized Relapse Rate decreased from 1.31 events/patient/year before treatment with natalizumab to 0 after 12 months of treatment and to 0.04 after 24 months. No gadolinium-enhancing lesions or new or enlarged T2 hyperintense lesions were observed in 8/8 patients (100%) after 12 months, and 4/5 (80%) after 24 months. There was one possible serious adverse event, which did not require dose adjustment. Five patients discontinued treatment due to positive anti-JCV (JC virus) antibody JC serostatus.

CONCLUSION

Natalizumab may be an effective and safe disease-modifying therapy for POMS. Our results are in line with data published for the adult population, as well as with similar observational studies in pediatric populations in other regions.

The epidemiology of multiple sclerosis in the entre Douro e Vouga region of northern Portugal: a multisource population-based study

BACKGROUND

The prevalence of Multiple Sclerosis (MS) has been increasing worldwide and the north-south gradient of prevalence may be disappearing in the Northern hemisphere. The few previous prevalence studies performed in Portugal have reported a lower prevalence than the average for Western Europe. The aim of this study is to estimate the prevalence of MS in the Entre Douro e Vouga region, in Northern Portugal.

METHODS

Multiple overlapping sources were used to ascertain all cases from the reference population: records from hospitals in the region and neighbouring regions; diagnostic databases of primary care physicians; and applications for disability benefits. The prevalence date was set at 1 January 2014. The reference population was 274,859 inhabitants. Patients' neurologists were contacted to retrieve clinical information and confirm the diagnosis based.

RESULTS

A total of 177 patients were identified after eliminating duplicates from different sources. The female to male ratio was 1.9 and the mean age at disease onset was 33.5 (standard deviation: 10.3). Clinically isolated syndrome accounted for 9.0% of patients, relapsing remitting for 58.8%, secondary progressive for 20.3% and primary progressive for 11.8%. The prevalence was estimated in 64.4 patients per 100,000 (95% confidence interval: 54.9;73.9).

CONCLUSIONS

In this study we report a higher point prevalence of MS than had been previously described in Portugal, but still far from the higher values recently reported in other Southern European countries.

JC virus antibodies in Portuguese multiple sclerosis patients: JUSTIFY study results

OBJECTIVE

To confirm anti-JC virus (JCV) antibody seroprevalence in Portuguese patients with relapsing-remitting multiple sclerosis (RRMS) and to determine their anti-JCV antibody index.

METHODS

JUSTIFY was a retrospective, multicentre study that included 655 RRMS patients tested at least once with the anti-JCV antibody assay STRATIFY JCV DxSelect. Demographic data, multiple sclerosis history and results of the anti-JCV antibody test were collected, along with physicians' reasons for requesting the test and the impact of the results.

RESULTS

Overall anti-JCV antibody seroprevalence was 60.8% (95% confidence interval, 56.9-64.5). Seroprevalence was associated with higher age (P = .030) and was lower in natalizumab-treated patients (P < .001). The mean anti-JCV antibody index of immunosuppressant-naive patients was 1.5 ± 1.3 (n = 378). The main reasons for performing the test were clinical characterization (35.5%) and medication change (26.2%). In patients who switched treatments (n = 109), fingolimod (47.7%) and natalizumab (26.6%) were the most commonly chosen new treatments.

CONCLUSIONS

The study confirmed the high anti-JCV antibody prevalence in Portuguese RRMS patients and its association with age. These data can be used to better understand the benefit-risk profile of natalizumab treatment in Portuguese patients and to support progressive multifocal leukoencephalopathy risk management strategies.

New insights into the burden and costs of multiple sclerosis in Europe: Results for Portugal

BACKGROUND

In order to assess the value of management strategies in multiple sclerosis (MS), outcome data have to be combined with cost data. This, in turn, requires that cost data be regularly updated.

OBJECTIVE AND METHODS

This study is part of a cross-sectional retrospective study in 16 countries collecting current data on resource consumption, work capacity and health-related quality of life (HRQoL). Descriptive analyses are presented by level of severity; costs are estimated in the societal perspective, in EUR 2015.

RESULTS

A total of 535 patients (mean age 48.5 years) participated; 92% were below retirement age and of these, 43% were employed. Employment was related to disease severity, and MS was felt to affect productivity at work by 72% of patients, most often through fatigue. Overall, 98% and 74% of patients felt that fatigue and cognition were a problem. Mean utility and costs were 0.756 and €16,500 at the Expanded Disability Status Scale (EDSS) 0-3, 0.572 and €28,700 at EDSS 4-6.5 and 0.206 and €34,400 at EDSS 7-9. The average cost of a relapse was estimated at €2930.

CONCLUSION

This study illustrates the burden of MS on Portuguese patients and provides current data that are important for the development of health policies.

Estimating the real incidence of invasive listeriosis through an integrated surveillance model in use in Lombardy (Italy, 2006-2014)

The annual incidence of listeriosis in Italy is lower (0·19-0·27 per 100 000 inhabitants per year) than in Europe (0·34-0·52 per 100 000 inhabitants per year). Since the observed incidence of listeriosis may be biased downward for underdiagnosis or under-reporting, this work aims to estimate the real incidence of listeriosis during a 9-year period in the Lombardy region, Italy. Data on listeriosis cases were collected from national mandatory notification system (MAINF) and Laboratory-based Surveillance System (LabSS). The two sources were cross-matched and capture-recapture method was applied to estimate the number of undetected cases and the real incidence of invasive listeriosis. Five hundred and eighty invasive listeriosis cases were detected by the two sources between 2006 and 2014: 50·2% were identified only via MAINF, 16·7% were recorded only via LabSS, overlaps occurred in 192 cases (33·1%). The mean annual incidence detected only by MAINF was 0·56 per 100 000 inhabitants, which rose to 0·67 per 100 000 considering also the cases detected by LabSS. The capture-recapture method allowed to estimate an incidence of 0·84 per 100 000. The high incidence of listeriosis may be due to improved sensitivity of the surveillance system, but also reflect a real increase, associated with an increased population at risk.

Multiple Sclerosis Epidemiology in Europe

Multiple sclerosis is characterized by a non-homogeneous distribution around the world. Some authors in past described a latitude gradient, with increasing risk from the equator to North and South Poles, but this theory is still controversial. Regarding Europe, there are many articles in the literature concerning the epidemiology of this disease but, unfortunately, they are not always comparable due to different methodologies, they do not cover all countries in the continent, and most of them reported data of small areas and rarely at a national level. In 2012 there were 20 national registries that could help to describe the epidemiology of the disease and, in addition, there is an European Register for Multiple Sclerosis that collect data from already existing national or regional MS registries and databases. Another valid alternative to obtain epidemiological data, also at national level, in a routinely and cost-saving way is through administrative data that are of increasing interest in the last years.

Estimation of perinatal mortality rate for institutional births in Rajasthan state, India, using capture-recapture technique

OBJECTIVE

The objective of our investigation was to estimate the perinatal mortality rate among institutional births and to compare the sensitivities of different data collection methods.

SETTING

A hospital-based prospective cohort study was undertaken during late-2012 in 21 public sector health facilities of 10 districts of the northern state of Rajasthan, India.

PARTICIPANTS

A total of 6872 births were included in this epidemiological study.

PRIMARY AND SECONDARY OUTCOME MEASURES

Perinatal mortality rate of institutional births was the primary outcome. Sensitivities of 'active' and passive' data collection methods were the secondary outcome measures.

METHODS

All stillbirth data were from routine government records ('passive system'); early neonatal outcome data from government records ('passive') were compared against the method of 'phone-tracking' of outcomes through the community health worker ('active system'). The Lincoln-Petersen formula for capture-recapture method was used to calculate the probable missing number of early neonatal deaths and thereby estimate the institutional perinatal mortality rate.

RESULTS

Ratio of births in district:subdistrict facilities was 55:45. The estimated perinatal mortality rate (95% CI) by capture-recapture method was 35.8 (34 to 37) per 1000 births. The sensitivity of the passive system was 87-89% while the sensitivity of the active system was 91%. Three-fourths of perinatal deaths were documented as stillbirths. However, for these reported intrauterine deaths or stillbirths, clinical classification by typologies (term vs preterm; intrapartum vs antepartum; macerated vs fresh; with or without congenital anomalies) was absent in the recording system.

CONCLUSIONS

Capture-recapture technique can be used to estimate the institutional perinatal mortality rate and also to assess the level of under-reporting by the 'passive' government reporting system. This can subsequently be used for monitoring of trends and studying the impact of health interventions. Accurate clinical categorisation of perinatal deaths is also recommended for improving quality of care.

MS Prevalence and Patients' Characteristics in the District of Braga, Portugal

Multiple Sclerosis (MS) is a chronic autoimmune disease of the Central Nervous System causing inflammation and neurodegeneration. There are only 3 epidemiological studies in Portugal, 2 in the Centre and 1 in the North, and there is the need to further study MS epidemiology in this country. The objective of this work is to contribute to the MS epidemiological knowledge in Portugal, describing the patients' epidemiological, demographic, and clinical characteristics in the Braga district of Portugal. This is a cross-sectional study of 345 patients followed in two hospitals of Braga district. These hospitals cover a resident population of 866,012 inhabitants. The data was collected from the clinical records, and 31/12/2009 was established as the prevalence day. For all MS patients, demographic characteristics and clinical outcomes are reported. We have found an incidence of 2.74/100,000 and a prevalence of 39.82/100,000 inhabitants. Most patients have an EDSS of 3 or lower and a mean age of 42 years. The diagnosis was done at mean age of 35, with RRMS being the disease type in more than 80% of patients. In this cohort, we found a female : male ratio of 1.79. More than 50% of patients are treated with Interferon β-1b IM or IFNβ-1a SC 22 μg.

Incidence of multiple sclerosis in Northern Lisbon, Portugal: 1998-2007

Background

There are few, recent, well assessed, multiple sclerosis (MS) incidence surveys on European populations. This study sought to measure MS incidence in a Northern Lisbon population and assess it using capture-recapture methods (CRMs).

Methods

Among the population residing in the Northern Lisbon Health Area, registered MS diagnoses were obtained from general practitioners in three primary-care districts covering a population of 196,300, and a neurology unit at the main referral hospital. Cases with onset during the periods 1978–1997 and 2008–2012 were excluded due to perceived poor access to image-supported neurological diagnosis and administrative changes in patient referral respectively. Age- and sex-specific incidences for the period 1998–2007 were calculated using McDonald diagnostic criteria, and CRMs were used to correct age-specific incidence rates. The corrected figures were also adjusted for age using the European Standard Population as reference.

Results

When applied to 62 MS patients with onset in the period 1998–2007, the rates per 100,000 population were as follows for both sexes: crude, 3.16; age-adjusted, 3.09 (95% CI 2.32 to 3.87); CRM-adjusted, 4.53 (95% CI 3.13 to 5.94); and age- and CRM-adjusted, 4.48 (3.54-5.41). In general, the rates were 3-fold higher among women than among men. Negative source dependency and CRM impact were highest at ages 35–44 years, where a 60% rise led to a peak incidence.

Conclusions

MS incidence in Northern Lisbon, Portugal, is moderately lower than that yielded by surveys on European populations. CRMs, which in this instance suggest undercounts, are a potentially useful tool for case-finding assessment but their application may introduce bias.

JCV epidemiology in MS (JEMS)--epidemiology of anti-JCV antibody prevalence in multiple sclerosis patients--Portuguese data

BACKGROUND

Progressive multifocal leukoencephalopathy, caused by oligodendrocyte lytic infection by JCVirus, is a growing concern for patients undergoing immune modulatory therapies for treatment of autoimmune diseases, such as multiple sclerosis (MS). The objective of JEMS was to describe the prevalence of anti-JCV antibodies in MS patients and to assess the various factors associated to it.

METHODS

Serum samples were collected and tested for anti-JCV antibody using the STRATIFY JCV™ assay in 131 Portuguese MS patients. Factors potentially associated with prevalence were also evaluated, as well as the effect of established risk factors.

RESULTS

In the population of 131 Portuguese patients included in the JEMS, the overall anti-JCV antibody prevalence was 69.5% (95% CI, 61.6-77.4). The anti-JCV antibody prevalence did not seem to be influenced by demographic characteristics, although results demonstrate a non-significant trend for increased prevalence with age. Disease characteristics, treatment duration, treatment history, prior immunosuppressive therapy use and natalizumab exposure duration did not seem to be associated with anti-JCV prevalence.

CONCLUSION

The results of Portuguese MS patients participating in the JEMS study present some differences when compared with the global population and literature results. An overall prevalence higher than expected raises awareness for data confirmation with greater sample size studies.

Incidence of multiple sclerosis among European Economic Area populations, 1985-2009: the framework for monitoring

Background

A debate surrounding multiple sclerosis epidemiology has centred on time-related incidence increases and the need of monitoring. The purpose of this study is to reassess multiple sclerosis incidence in the European Economic Area.

Methods

We conducted a systematic review of literature from 1965 onwards and integrated elements of original research, including requested or completed data by surveys authors and specific analyses.

Results

The review of 5323 documents yielded ten studies for age- and sex-specific analyses, and 21 studies for time-trend analysis of single data sets. After 1985, the incidence of multiple sclerosis ranged from 1.12 to 6.96 per 100,000 population, was higher in females, tripled with latitude, and doubled with study midpoint year. The north registered increasing trends from the 1960s and 1970s, with a historic drop in the Faroe Islands, and fairly stable data in the period 1980-2000; incidence rose in Italian and French populations in the period 1970-2000, in Evros (Greece) in the 1980s, and in the French West Indies in around 2000.

Conclusions

We conclude that the increase in multiple sclerosis incidence is only apparent, and that it is not specific to women. Monitoring of multiple sclerosis incidence might be appropriate for the European Economic Area.

Incidence and prevalence of multiple sclerosis in the Americas: a systematic review

BACKGROUND

The incidence and prevalence of multiple sclerosis (MS) varies considerably around the world. No previous study has performed a comprehensive review examining the incidence and prevalence of MS across the Americas. The purpose of this study was to systematically review and assess the quality of studies estimating the incidence and/or prevalence of MS in North, Central and South American regions.

METHODS

A comprehensive literature search was performed using MEDLINE and EMBASE from January 1985 to January 2011. Search terms included 'multiple sclerosis', 'incidence', 'prevalence' and 'epidemiology'. Only full-text articles published in English or French were included. Study quality was assessed using an assessment tool based on recognized guidelines and designed specifically for this study.

RESULTS

A total of 3,925 studies were initially identified, with 31 meeting the inclusion criteria. The majority of studies examined North American regions (n = 25). Heterogeneity was high among all studies, even when stratified by country. Only half of the studies reported standardized rates, making comparisons difficult. Quality scores ranged from 3/8 to 8/8.

CONCLUSION

This review highlights the gaps that still exist in the epidemiological knowledge of MS in the Americas, and the inconsistencies in methodologies and quality among the published studies. There is a need for future studies of MS prevalence and incidence to include uniform case definitions, employ comparable methods of ascertainment, report standardized results, and be performed on a national level. Other factors such as sex distribution, ethnic make-up and population lifestyle habits should also be considered.