Registers of multiple sclerosis in Denmark

Data monitoring roadmap. The experience of the Italian Multiple Sclerosis and Related Disorders Register

INTRODUCTION

Over the years, disease registers have been increasingly considered a source of reliable and valuable population studies. However, the validity and reliability of data from registers may be limited by missing data, selection bias or data quality not adequately evaluated or checked. This study reports the analysis of the consistency and completeness of the data in the Italian Multiple Sclerosis and Related Disorders Register.

METHODS

The Register collects, through a standardized Web-based Application, unique patients. Data are exported bimonthly and evaluated to assess the updating and completeness, and to check the quality and consistency. Eight clinical indicators are evaluated.

RESULTS

The Register counts 77,628 patients registered by 126 centres. The number of centres has increased over time, as their capacity to collect patients. The percentages of updated patients (with at least one visit in the last 24 months) have increased from 33% (enrolment period 2000-2015) to 60% (enrolment period 2016-2022). In the cohort of patients registered after 2016, there were ≥ 75% updated patients in 30% of the small centres (33), in 9% of the medium centres (11), and in all the large centres (2). Clinical indicators show significant improvement for the active patients, expanded disability status scale every 6 months or once every 12 months, visits every 6 months, first visit within 1 year and MRI every 12 months.

CONCLUSIONS

Data from disease registers provide guidance for evidence-based health policies and research, so methods and strategies ensuring their quality and reliability are crucial and have several potential applications.

Natalizumab treatment of multiple sclerosis - a Danish nationwide study with 13 years of follow-up

BACKGROUND

Natalizumab is a widely used high-efficacy treatment in multiple sclerosis (MS). Real-world evidence regarding long-term effectiveness and safety is warranted. We performed a nationwide study evaluating prescription patterns, effectiveness, and adverse events.

METHODS

A nationwide cohort study using the Danish MS Registry. Patients initiating natalizumab between June 2006 and April 2020 were included. Patient characteristics, annualized relapse rates (ARRs), confirmed Expanded Disability Status Scale (EDSS) score worsening, MRI activity (new/enlarging T2- or gadolinium-enhancing lesions), and reported adverse events were evaluated. Further, prescription patterns and outcomes across different time periods ("epochs") were analysed.

RESULTS

In total, 2424 patients were enrolled, with a median follow-up time of 2.7 years (interquartile range (IQR) 1.2-5.1). In recent epochs, patients were younger, had lower EDSS scores, had fewer pre-treatment relapses and were more often treatment naïve. At 13 years of follow-up, 36% had a confirmed EDSS worsening. On-treatment ARR was 0.30, corresponding to a 72% reduction from pre-initiation. MRI activity was rare, 6.8% had activity within 2-14 months from treatment start, 3.4% within 14-26 months, and 2.7% within 26-38 months. Approximately 14% of patients reported adverse events, with cephalalgia constituting the majority. During the study, 62.3% discontinued treatment. Of these, the main cause (41%) was due to JCV antibodies, while discontinuations due to disease activity (9%) or adverse events (9%) were less frequent.

CONCLUSION

Natalizumab is increasingly used earlier in the disease course. Most patients treated with natalizumab are clinically stable with few adverse events. JCV antibodies constitute the main cause for discontinuation.

Changes in prognosis of the Danish multiple sclerosis population over time

BACKGROUND

The course of multiple sclerosis (MS) appears to be milder in recent decades.

OBJECTIVE

To investigate how time from onset to disability milestones and how demographic and clinical characteristics have changed through subsequent onset cohorts of patients with MS.

METHODS

In the nationwide Danish Multiple Sclerosis Registry, we have registered all 13,562 Danish patients with onset of MS or clinically isolated syndrome from 1996 through 2020. For the analyses of prognosis, we used all cases with relapsing onset (N = 11,669). After stratification into 5-year onset cohorts, we computed the hazard ratios for disability endpoints for all cohorts having at least 10 years of follow-up and the oldest 1996-2000 onset cohort as reference.

RESULTS

Patients in more recent MS onset cohorts have a shorter diagnostic delay and more of them start disease-modifying treatment within 1 year since diagnosis. The prognosis was better for later onset cohorts. For the 2001-2005 cohort, the hazard ratio for confirmed Expanded Disability Status Scale (EDSS) 4 was 0.85 (95% confidence interval (CI), 0.76-0.95) and for confirmed EDSS 6: 0.76 (95% CI, 0.65-0.88). For the more recent 2006-2010 cohort, the corresponding hazard ratios were 0.70 (95% CI, 0.62-0.79) and 0.60 (95% CI, 0.50-0.71).

CONCLUSION

We observed a considerable improvement of the prognosis in recent onset cohorts of relapsing-onset MS.

Incidence of malignancy in multiple sclerosis: A cohort study in the Danish Multiple Sclerosis Registry

Background

The association between multiple sclerosis and malignancy is controversial and a current appraisal is needed.

Objective

To determine the incidence of malignancy in patients with multiple sclerosis compared with the general population and in relation to disease-modifying therapy.

Methods

Patients with multiple sclerosis (1995 – 2015) were matched by birth year and sex to individuals without multiple sclerosis in the general population. Patients with multiple sclerosis initiating disease-modifying therapy were evaluated using landmark period analysis. Malignancy risk was assessed by incidence rates, incidence rate ratios, and standardised incidence ratios.

Results

The standardised incidence ratio of any malignancy (excluding non-melanoma skin cancer) in patients with multiple sclerosis (n = 10,557) was 0.96 (95% CI 0.88 – 1.06), and there was no increased incidence of specific malignancy types compared with the general population cohort (n = 103,761). At the 48-month landmark period, the age-adjusted incidence per 100,000 person-years of any malignancy (excluding non-melanoma skin cancer) was 436.7 (95% CI 361.0 – 512.4) in patients newly treated with immunomodulator-only and 675.1 (95% CI 130.4 – 1219.9) in patients newly treated with immunosuppressant-only.

Conclusions

There was no increased incidence of malignancy overall or by type in patients with multiple sclerosis compared neither with the general population nor in relation to disease-modifying therapy.

Natalizumab Versus Fingolimod in Patients with Relapsing-Remitting Multiple Sclerosis: A Subgroup Analysis From Three International Cohorts

INTRODUCTION

Natalizumab has proved to be more effective than fingolimod in reducing disease activity in relapsing-remitting multiple sclerosis (RRMS). Whether this association is universal for all patient groups remains to be determined.

OBJECTIVE

The aim of this study was to compare the relative effectiveness of natalizumab and fingolimod in RRMS subgroups defined by the baseline demographic and clinical characteristics of interest.

METHODS

Patients with RRMS who were given natalizumab or fingolimod were identified in a merged cohort from three international registries. Efficacy outcomes were compared across subgroups based on patients' sex, age, disease duration, Expanded Disability Status Scale (EDSS) score, and disease and magnetic resonance imaging (MRI) activity 12 months prior to treatment initiation. Study endpoints were number of relapses (analyzed with weighted negative binomial generalized linear model) and 6-month confirmed disability worsening and improvement events (weighted Cox proportional hazards model), recorded during study therapy. Each patient was weighted using inverse probability of treatment weighting based on propensity score.

RESULTS

A total of 5148 patients (natalizumab 1989; fingolimod 3159) were included, with a mean ± standard deviation age at baseline of 38 ± 10 years, and the majority (72%) were women. The median on-treatment follow-up was 25 (quartiles 15-41) months. Natalizumab was associated with fewer relapses than fingolimod (incidence rate ratio [IRR]; 95% confidence interval [CI]) in women (0.76; 0.65-0.88); in those aged ≤ 38 years (0.64; 0.54-0.76); in those with disease duration ≤ 7 years (0.63; 0.53-0.76); in those with EDSS score < 4 (0.75; 0.64-0.88), < 6 (0.80; 0.70-0.91), and ≥ 6 (0.52; 0.31-0.86); and in patients with pre-baseline relapses (0.74; 0.64-0.86). A higher probability of confirmed disability improvement on natalizumab versus fingolimod (hazard ratio [HR]; 95% CI) was observed among women (1.36; 1.10-1.66); those aged > 38 years (1.34; 1.04-1.73); those with disease duration > 7 years (1.33; 1.01-1.74); those with EDSS score < 6 (1.21; 1.01-1.46) and ≥ 6 (1.93; 1.11-3.34); and patients with no new MRI lesion (1.73; 1.19-2.51).

CONCLUSIONS

Overall, in women, younger patients, those with shorter disease durations, and patients with pre-treatment relapses, natalizumab was associated with a lower frequency of multiple sclerosis relapses than fingolimod. It was also associated with an increased chance of recovery from disability among most patients, particularly women and those with no recent MRI activity.

Pregnancy-Related and Perinatal Outcomes in Women With Multiple Sclerosis: A Nationwide Danish Cross-sectional Study

OBJECTIVE

To investigate differences in pregnancy-related and perinatal outcomes in women with multiple sclerosis (MS) compared with the general population.

METHODS

We conducted a cross-sectional study including pregnancies from January 1, 1997, to December 31, 2016, to women registered in the Danish Multiple Sclerosis Registry (the study cohort). Pregnancy-related and perinatal outcomes were compared with a randomly selected subcohort of pregnancies from the general population (the comparison cohort) using logistic regression adjusted for possible confounders.

RESULTS

In total, 2,930 pregnancies were included in the study cohort and 56,958 pregnancies in the comparison cohort. No differences were found in pregnancy-related complications (preeclampsia/gestational diabetes or placenta complications), emergency caesarean section (c-section), instrumental delivery, low Apgar score, stillbirth, preterm birth, or congenital malformations. Elective c-section (odds ratio [OR] 1.89 [95% confidence interval (CI) 1.65-2.16]), induced delivery (OR 1.15 [95% CI 1.01-1.31]), and being born small for gestational age (SGA) (OR 1.29 [95 %CI 1.04-1.60]) had a higher prevalence in the study cohort, whereas the prevalence of signs indicating asphyxia was lower in the study cohort (OR 0.87 [95% CI 0.78-0.97]) relative to the comparison cohort.

CONCLUSION

We found a higher prevalence of elective c-sections, induced delivery, and infants being SGA among newborns to women with MS, whereas the prevalence of asphyxia was lower in the study cohort. There were no significant differences in severe adverse perinatal outcomes when comparing women with MS and their newborns with those of the general population.

The effectiveness of natalizumab vs fingolimod-A comparison of international registry studies

BACKGROUND

Natalizumab and fingolimod were the first preparations recommended for disease breakthrough in priorly treated relapsing-remitting multiple sclerosis. Of three published head-to-head studies two showed that natalizumab is the more effective to prevent relapses and EDSS worsening.

METHODS

By re-analyzing original published results from MSBase, France, and Denmark using uniform methodologies, we aimed at identifying the effects of differences in methodology, in the MS-populations, and at re-evaluating the differences in effectiveness between the two drugs. We gained access to copies of the individual amended databases and pooled all data. We used uniform inclusion/exclusion criteria and statistical methods with Inverse Probability Treatment Weighting.

RESULTS

The pooled analyses comprised 968 natalizumab- and 1479 fingolimod treated patients. The on-treatment natalizumab/fingolimod relapse rate ratio was 0.77 (p=0.004). The hazard ratio (HR) for a first relapse was 0.82 (p=0.030), and the HR for sustained EDSS improvement was 1.4 (p=0.009). There were modest differences between each of the original published studies and the replication study, but the conclusions of the three original studies remained unchanged: in two of them natalizumab was more effective, but in the third there was no difference between natalizumab and fingolimod.

CONCLUSION

The results were largely invariant to the epidemiological and statistical methods but differed between the MS populations. Generally, the advantage of natalizumab was confirmed.

Effect of lateral therapy switches to oral moderate-efficacy drugs in multiple sclerosis: a nationwide cohort study

BACKGROUND

Switching between first-line disease-modifying therapies in patients with clinically stable relapsing-remitting multiple sclerosis (RRMS) due to reasons other than disease activity is frequent, but evidence on the effect of this practice is limited. We investigated the effect of switching patients with stable RRMS on occurrences of disability accumulation, relapses and future treatment discontinuation.

METHODS

Using the Danish Multiple Sclerosis Registry, we identified patients with RRMS without disease activity who either (1) stayed on injectable platform therapy (interferon-β or glatiramer acetate) or (2) switched to dimethyl fumarate (DMF) or teriflunomide (TFL) and compared treatment outcomes using propensity-score-based methods and marginal structural models (MSM).

RESULTS

We included 3206 patients in the study. We found no change in risk of 6-month confirmed Expanded Disability Status Scale score worsening in patients switching to DMF (HR: 1.15, 95% CI 0.88 to 1.50) or TFL (HR: 1.16, 95% CI 0.92 to 1.46). The risk of suffering any relapse tended to decrease when switching to DMF (HR: 0.73, 95% CI 0.51 to 1.04) and tended to increase when switching to TFL (HR: 1.25, 95% CI 0.96 to 1.63). Absolute risk differences were small. MSM analyses showed similar results but did not find an increased relapse risk in TFL switchers.

CONCLUSION

Switching from injectable platform therapies to oral first-line therapies in patients with clinically stable RRMS does not increase the risk of disability accumulation. While the postswitch risk of relapses trended towards marginally higher on TFL, this trend was eliminated by adjustment for time-variant confounders.

Alemtuzumab treatment in Denmark: A national study based on the Danish Multiple Sclerosis Registry

OBJECTIVE

To investigate clinical outcomes in a real-world setting in the complete population-based cohort of alemtuzumab-treated MS patients in Denmark.

METHODS

Data were retrieved from The Danish Multiple Sclerosis Registry between 2009 and 2019. Demographic and disease-specific patient parameters related to treatment history, efficacy, and safety outcomes were assessed at baseline and during follow-up visits.

RESULTS

A total of 209 patients (78% female) started treatment with alemtuzumab during the study period with 3.1 ± 1.4 years follow-up. After 2 years, 75% of patients were relapse-free compared to 48% the year before alemtuzumab (p < 0.001). The annual number of relapses was reduced by 69% in year 4 compared with the year prior alemtuzumab. More active disease before alemtuzumab increased the annual hazard rate for relapse (HR: 2.88, p < 0.001). The Expanded Disability Status Scale (EDSS) score remained stable or improved in 81% of patients after 2 years. The need for an additional treatment course was associated with higher number of relapses in the year before alemtuzumab (odds ratio (OR) = 1.95, p = 0.001).

CONCLUSION

In a country with primarily escalation strategy, relapse rate reduction was maintained for 5 years, and EDSS stabilized/improved in majority of patients. Higher relapse rate 1 year before alemtuzumab increased the odds for additional courses. Novel serious AEs were not observed.

Age and sex as determinants of treatment decisions in patients with relapsing-remitting MS

BACKGROUND

. Most patients with relapsing-remitting multiple sclerosis (RRMS) are initially treated with moderate efficacy disease-modifying therapies (meDMTs), and only a smaller group of highly active patients are initiated on a high efficacy disease-modifying therapy (heDMT). Real-world data have shown that choosing a heDMT as the initial therapy in highly active RRMS patients is more effective than using a meDMT, and that in patients with breakthrough disease on a meDMT escalation of treatment to a heDMT is more effective than staying on the same or switching to another meDMT. The role of age and sex as determinants for selection of the initial treatment intensity, and for using escalation of treatment intensity in patients with relapse activity on treatment with meDMTs, is only partially known.

METHODS

. We included all Danish patients with RRMS registered in The Danish Multiple Sclerosis Registry who began a DMT since 2014 and stratified the cohort according to sex and age < 40 and ≥ 40 years at first DMT treatment. We studied determinants, with emphasis on age and sex, for the primary choice of therapy, for adherence to the initial therapy and for treatment escalation. Based on existing literature and clinical relevance, we included the following potential confounders in the analyses: DMT efficacy, pre-treatment relapse activity, disease duration, Expanded Disability Status Scale (EDSS) score, and, in a subgroup, MRI activity.

RESULTS

. With all covariates mutually adjusted, patient age was a strong decisive factor for choosing a heDMT with odds ratio 1.69 for starting a heDMT in patients < 40 years compared with patients ≥ 40 years. Men had odds ratio 1.53 for starting with a heDMT compared with women. The odds ratio of heDMT in patients with EDSS > 3 vs ≤ 3 was 3.49, and every additional relapse was associated with increased odds ratio 2.33 for heDMT. Patients were more adherent to the initial heDMTs than to the initial meDMTs. Patients above 40 years were more prone to stay on the initial treatment compared to patients below 40, regardless of whether the initial treatment was meDMT (p<0.001) or heDMT (p=0.008) (covariates mutually adjusted). Relapse activity resulted in escalation of therapy to a heDMT in 67% of patients aged < 40 years (N=273) and in 56% patients aged 40 years or above (N=159) (p=0.008), and younger patients had odds ratio 1.46 of escalating therapy compared to older patients. Male patients were more likely to have treatment escalation to heDMTs than female patients (odds ratio 2.03).

CONCLUSION

. Age and sex appear to be independent determinants for the choice of the initial DMT and for the decision of treatment escalation in patients with breakthrough disease on a meDMT. It is unfortunate, if older age is a factor that make choice of a heDMT more unlikely, as many DMTs seems to be less efficacious in older patients.

Seasonal patterns of relapse and disability in Danish MS patients: A population-based cohort study

BACKGROUND

The importance of environmental risk factors in the onset of multiple sclerosis (MS) has been studied extensively. Similarly, a growing number of studies address the importance of environmental factors, including seasonality, for ongoing activity of established disease. Specifically, past research demonstrates higher rates of relapse activity in summer months among individuals with MS. Our study adds to the existing literature on seasonality of disease relapse by analysing a large population-based and virtually complete cohort of patient with relapsing and remitting MS (RRMS) in an area of temperate climate.

METHODS

The Danish Multiple Sclerosis Registry includes follow-up for all patients receiving disease modifying treatment from 1996-2020, with near-complete registration of all relapses and their dates. We compared the observed and expected numbers of relapses for each calendar month and calculated month-specific annualized relapse rates (ARR) using Poisson regression. In addition, we analysed seasonal variation in disability as measured by the Expanded Disability Status Scale (EDSS).

RESULTS

From 1996 to 2020 we followed 13,575 MS patients treated with disease modifying therapy (4165 men and 9410 women) for a total of 82,187 person years and 134,593 control visits. The mean age at entry was 41.1 years with standard deviation 10.9 years. We recorded 16,083 relapses throughout the observation period, and for 15,728 of the relapses the date of onset was known. Relapses were unevenly distributed by calendar month (p < 0.00001). The most prominent deviation was a paucity of relapses in July in which the ARR was 0.166 compared with mean of 0.191 for the whole year. Otherwise, the ARR formed a plateau slightly above mean during the spring months. Mean EDSS was slightly higher in autumn (2.78) than in spring (2.74), but there was no difference between winter and summer; p < 0.0001.

CONCLUSION

In contrast with previous studies, we observed a nadir of relapses in July among Danish patients with RRMS. This finding may be related to increased exposure to sunlight in the summer, particularly during vacation when outdoor recreational activities are more frequent and potential exposure to infections is decreased. Confirmation of this in future studies is warranted.

Maternal diabetes and risk of multiple sclerosis in the offspring: A Danish nationwide register-based cohort study

BACKGROUND

Previous studies suggest a 3- to-10-fold increased risk of multiple sclerosis (MS) in offspring of mothers with diabetes mellitus (DM).

OBJECTIVES

To examine MS risk in offspring of diabetic mothers, overall and according to type of maternal DM, that is, pregestational DM or gestational DM, as well as to examine MS risk among offspring of diabetic fathers.

METHODS

The study cohort included all 1,633,436 singletons born in Denmark between 1978 and 2008. MS diagnoses were identified in the Danish Multiple Sclerosis Registry, and parental DM diagnoses in the National Patient Register. We used Cox proportional hazards regression analyses to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) for the association of parental DM with MS risk in the offspring.

RESULTS

MS risk among individuals whose mothers had pregestational DM was 2.3-fold increased compared with that among individuals with nondiabetic mothers (HR = 2.25; 95% CI: 1.35-3.75, n = 15). MS risk was statistically non-significant among offspring of mothers with gestational DM (HR = 1.03 (95% CI: 0.49-2.16), n = 7) and among offspring of diabetic fathers (HR = 1.40 (95% CI: 0.78-2.54), n = 11).

CONCLUSION

Our nationwide cohort study utilizing high-quality register data in Denmark over several decades corroborates the view that offspring of diabetic mothers may be at an elevated risk of developing MS.

Increased socioeconomic burden in patients with primary progressive multiple sclerosis: A Danish nationwide population-based study

BACKGROUND

Primary progressive multiple sclerosis (PPMS) is characterized by development of more chronic neurological manifestations from disease onset compared with relapsing remitting MS (RRMS) and secondary progressive MS (SPMS) but the following socioeconomic consequences have never been described in a nation-wide patient population.

OBJECTIVE

To determine if socioeconomic burden of PPMS is increased compared with RRMS and SPMS.

METHODS

We included patients from The Danish Multiple Sclerosis Registry diagnosed between 1998 and 2015. Yearly average health costs, public transfers and earned income was calculated from the index diagnosis date, and each year in a five-year period before and after index diagnosis date, for the three patient groups. A regression model estimating the odds ratio (OR) with PPMS as the comparator, was used to analyze the differences between PPMS vs. RRMS and PPMS vs. SPMS controlling for age and sex.

RESULTS

In total, 9563 MS patients were identified (1998-2015), with a characteristic distribution between different disease courses: 7012 patients with RRMS (73%), 1099 patients with PPMS (11%) and 1452 patients with SPMS (15%). Total health costs were lower in RRMS vs. PPMS (OR 0.76; 95% CI 0.74-0.78; p<0.0001) but not in SPMS vs. PPMS (OR 1.06; 95% CI 1.03-1.09; p<0.0001). Especially homecare costs were lower in RRMS vs. PPMS (OR 0.17; 95% CI 0.17-0.18; p<0.0001), less pronounced in SPMS vs. PPMS (OR 0.93; 95% CI 0.90-0.97; p = 0.0001). OR for health costs before and after diagnosis was significantly lower in RRMS vs. PPMS regarding most variables, less pronounced in SPMS vs. PPMS.

CONCLUSION

This nation-wide population-based study show that socioeconomic burden is significantly higher in PPMS relative to RRMS, but less pronounced compared with SPMS.

Multiple sclerosis among first- and second-generation immigrants in Denmark: a population-based cohort study

Multiple sclerosis is a disease with a highly variable incidence worldwide. While knowledge about multiple sclerosis risk factors has grown over the years, the aetiology of multiple sclerosis has still not been fully established. We examined multiple sclerosis incidence rates among first-generation immigrants in Denmark, a high-incidence country, and their Danish-born children (second-generation immigrants), to evaluate the importance and timing of exposure to environmental factors in the aetiology of multiple sclerosis. By means of the Danish Civil Registration System we identified 9 121 187 individuals living in Denmark between 1968 and 2015, including 1 176 419 first-generation and 184 282 second-generation immigrants. Study participants were followed for multiple sclerosis in the Danish Multiple Sclerosis Registry from 1968 to 2015. The relative risk (RR) of multiple sclerosis according to immigration status was estimated by means of multiple sclerosis incidence rate ratios obtained in log-linear Poisson regression analysis. Altogether, 16 905 cases of multiple sclerosis were identified in the study cohort, 578 among first-generation and 106 among second-generation immigrants. Multiple sclerosis risk among first-generation immigrants whose parents were born in low, intermediate and high multiple sclerosis risk areas were 21% (RR = 0.21; 95% CI: 0.16-0.28), 43% (RR = 0.43; 95% CI: 0.36-0.50) and 75% (RR = 0.75; 95% CI: 0.67-0.83), respectively, of that among ethnic Danes (test for trend P < 0.0001). First-generation immigrants arriving in Denmark before age 15 years had a multiple sclerosis risk higher than that in their country of birth but lower than that in Denmark, reaching on average 69% of the multiple sclerosis risk among ethnic Danes (RR = 0.69; 95% CI: 0.55-0.87). Multiple sclerosis risk among individuals who came to Denmark at a later age remained closer to that of their country of birth, corresponding to 45% of the multiple sclerosis risk among ethnic Danes (RR = 0.45; 95% CI: 0.41-0.49). Our study supports the idea that environmental factors exerting their role in childhood or adolescence may be of aetiological relevance in multiple sclerosis.

Clinically stable disease is associated with a lower risk of both income loss and disability pension for patients with multiple sclerosis

OBJECTIVE

To assess the risk of losing income from salaries and risk disability pension for multiple sclerosis patients with a clinically stable disease course 3 years after the start of disease-modifying therapy (DMT).

METHODS

Data from the Danish Multiple Sclerosis Registry were linked to other Danish nationwide population-based databases. We included patients who started treatment with a DMT between 2001 and 2014. Patients were categorised into a clinically stable group (No Evidence of Disease Activity (NEDA-2)) and a clinically active group (relapse activity or 6-month confirmed Expanded Disability Status Scale worsening). Outcomes were: (1) loss of regular income from salaries and (2) a transfer payment labelled as disability pension. We used a Cox proportional hazards model to estimate confounder-adjusted HRs, and absolute risks were plotted using cumulative incidence curves accounting for competing risks.

RESULTS

We included 2406 patients for the income analyses and 3123 patients for the disability pension analysis. Median follow-up from index date was ~5 years in both analyses. The NEDA-2 group had a 26% reduced rate of losing income (HR 0.74; 95% CI 0.60 to 0.92). HRs were calculated for 5-year intervals in the disability pension analysis: year 0-5: a 57% reduced rate of disability pension for the NEDA-2 group (HR 0.43; 95% CI 0.33 to 0.55) and year 5-10: a 36% reduced rate (HR 0.64; 95% CI 0.40 to 1.01).

CONCLUSION

Clinically stable disease course (NEDA-2) is associated with a reduced risk of losing income from salaries and a reduced risk of disability pension.

Observational designs in clinical multiple sclerosis research: Particulars, practices and potentialities

Observational studies investigate a wide range of topics in multiple sclerosis research. This paper presents an overview of the various observational designs and their applications in clinical studies. Observational studies are well suited for making discoveries and assessing new explanations of phenomena, but less so for establishing causal relationships, due to confounding by indication (selection bias), co-morbidity, socio-economic or other factors. Whether observational findings are demonstrative, indicative or only suggestive, depends on the research question, whether and how the design fits this question, analytical techniques, and the quality of data. Observational studies may be cross-sectional vs. longitudinal, and prospective vs. retrospective. The term 'retrograde' is proposed to explicate that cross-sectional studies may obtain data that cover (long) preceding periods. Case reports and case series are usually based on accidental observations or routinely collected data. Cross-sectional studies, by simultaneously assessing clinical phenomena and external factors, enable the discovery and quantification of associations. In ecological studies the unit of analysis is population or group, and relationships on patient level cannot be established. A cohort study is a longitudinal study that investigates patients with a defining characteristic, e.g. diagnosis or specific treatment, by analyzing data acquired at various intervals. Prospective cohort studies use (some) data that are not yet available at the time the research is conceived, whereas in retrospective studies the data already exist. In a case-control study a representative group of patients with a specific clinical feature is compared with controls, and the frequencies at which an external factor, e.g. infection, has occurred in each group is compared; in a nested case-control study controls are drawn from a fully known cohort. Randomized controlled trial (RCT)-extension studies are informative because, due to RCT randomization, they are free from confounding by indication. Patient or disease registries are organised systems for the long-term collection of uniform data on a population that is defined by a particular disease, condition or exposure, with the purpose to study changes over time. In pharmacotherapeutic research, accidental observations of unexpected beneficial effects may lead to further research into a drug's efficacy in other conditions. Uncontrolled phase 1 studies investigate safety and dosing aspects. Observational studies are alternatives to RCTs when these are not feasible for ethical or practical reasons. Phase 4 observational studies play a crucial role in the evaluation of the effectiveness of treatments in daily practice, the validation of RCT-based side effect profiles, and the discovery of late occurring or rare, potentially life-threatening side effects. Combinations of multidisciplinary longitudinal data bases into large data sets enable the development of algorithms for personalized treatments. To improve the reporting of observational findings on treatment effectiveness, it is proposed that abstracts define the research question(s) the study was meant to answer, study design and analytical methods, and identify and quantify the patient population, treatment of interest, relevant outcomes and the study's strengths and limitations. The development of guidelines for Strengthening the Reporting of Observational Studies in Effectiveness Research (STROBER), as an extension of the guidelines used in epidemiology, is wanted.

Incidence of pediatric neuromyelitis optica spectrum disorder and myelin oligodendrocyte glycoprotein antibody-associated disease in Denmark 2008‒2018: A nationwide, population-based cohort study

BACKGROUND

The incidence of pediatric neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease have not been reported previously. Our aim was to estimate the incidence of pediatric NMOSD and the occurrence of anti-MOG antibody-associated disease in Denmark during 2008-18, and to evaluate the diagnostic usefulness of antibodies against MOG and aquaporin-4 (AQP4) in children <18 years.

METHODS

We undertook a nationwide, population-based, multicenter cohort study using data from the Danish National Patient Register, the Danish Multiple Sclerosis Registry, and laboratories providing anti-AQP4 and anti-MOG antibody analyses. Diagnoses were confirmed by review of the medical records, including blinded MRI review in most children with acute disseminated encephalomyelitis (ADEM).

RESULTS

In children with acquired demyelinating syndromes, anti-AQP4 antibodies were detected in 4% and anti-MOG antibodies in 18%, including in the two children with ADEM who relapsed. We identified four children with NMOSD, equivalent to an incidence of 0.031/100,000 (95% confidence interval = 0.011‒0.082). In anti-MOG antibody-positive children, 32% relapsed during follow-up.

CONCLUSIONS

Pediatric NMOSD and MOG antibody-associated disease are rare, but one-third of anti-MOG-positive children relapsed. In pediatric ADEM, only anti-MOG antibody-positive children relapsed, but the overall risk of relapse after pediatric ADEM was low.

Reproductive history of the Danish multiple sclerosis population: A register-based study

Background:

A diagnosis of multiple sclerosis (MS) may impact the choice of parenthood.

Objective:

To investigate the number of live births, abortions and ectopic pregnancies among persons with MS.

Methods:

From the Danish Multiple Sclerosis Registry, we extracted data from all persons diagnosed with MS from 1960 to 1996 and matched each MS person with four reference persons. We used a negative binomial regression model for the live births and Poisson regression model for abortions and ectopic pregnancies. The total fertility rate (TFR) during 1960–2016 and the annual number of live births in the MS population were analysed.

Results:

Persons with MS had fewer children than reference persons. Fewer women with MS had elective abortions after diagnosis (incidence rate ratio (IRR) = 0.88; 95% confidence interval (CI) = 0.78–1.00) than reference persons. There was no difference regarding the number of elective abortions, spontaneous abortions or ectopic pregnancies after onset. The TFR was lower for women with MS than for reference persons, and the number of annual live births by MS persons increased during 1960–2016.

Conclusion:

MS seems to considerably impact reproductive choices, especially after clinical diagnosis, resulting in the MS population having fewer children than the general population.

Predictors of treatment outcome in patients with paediatric onset multiple sclerosis

BACKGROUND

Disease-modifying therapies (DMT) are increasingly used for children with multiple sclerosis (MS) even though most double-blinded randomized controlled trials evaluating efficacy, safety and dosing strategy of a specific drug have included adults.

OBJECTIVE

To investigate predictors of treatment outcomes in patients with paediatric onset MS treated with DMTs.

METHODS

Prospective cohort study from the nationwide Danish Multiple Sclerosis Registry including all patients with a MS diagnosis who initiated treatment with an approved DMT before the age of 18 (N = 137) and followed until their 25th birthday. Selected baseline predictors were tested in univariate and multivariate regression models.

RESULTS

Multivariate analyses showed that being female and having disease duration for 2 or more years prior to DMT initiation predicted a higher relapse rate. In addition, disease duration and baseline expanded disability status scale (EDSS) predicted both confirmed disability worsening and improvement. We found no difference in treatment outcome between children with MS onset before and after the age of 13 years.

CONCLUSIONS

The efficacy of DMT in paediatric onset MS patients is comparable to that seen in adult onset MS patients. Earlier treatment start is associated with a beneficial prognosis in the paediatric cohort.

Impact of red meat, processed meat and fibre intake on risk of late-onset chronic inflammatory diseases: prospective cohort study on lifestyle factors using the Danish 'Diet, Cancer and Health' cohort (PROCID-DCH): protocol

INTRODUCTION

Chronic inflammatory diseases (CIDs) (Crohn's disease, ulcerative colitis, psoriasis, psoriatic arthritis, rheumatoid arthritis and multiple sclerosis) are diseases of the immune system that have some shared genetic and environmental predisposing factors, but still few studies have investigated the effects of lifestyle on disease risk of several CIDs. The primary aim of this prospective cohort study is to investigate the impact of fibre, red meat and processed meat on risk of late-onset CID, with the perspective that results of this study can contribute in supporting future diet recommendations for effective personalised prevention.

METHODS AND ANALYSIS

The study will use data from 57 053 persons from the prospective Danish cohort study 'Diet, Cancer and Health' together with National Health Registry data. The follow-up period is from December 1993 to December 2018. Questionnaire data on diet and lifestyle were collected at entry to the Diet, Cancer and Health study. The outcome CID is defined as having a diagnosis of one of the CIDs registered in the National Patient Registry or, for multiple sclerosis, in the Danish Multiple Sclerosis Registry during follow-up and being treated with a drug used for the specific disease. The major outcome of the analyses will be to detect variability in risk of late onset of any CID and, if power allows, disease risk of late onset of each CID diagnosis between persons with different fibre and red meat, and processed meat intake. The outcome will be adjusted for age, sex, body mass index, physical activity, energy, alcohol, fermented dairy products, education, smoking status, hormone replacement therapy and comorbidity.

ETHICS AND DISSEMINATION

The study is approved by the Danish Data Protection Agency (2012-58-0018). The core study is an open register-based cohort study. The study does not need approval from the Ethics committee or Institutional Review Board by Danish law. Study findings will be disseminated through peer-reviewed journals, patient associations and presentations at international conferences.

TRIAL REGISTRATION NUMBER

NCT03456206; Post-results.

Comparative effectiveness of teriflunomide and dimethyl fumarate: A nationwide cohort study

OBJECTIVE

To compare on-treatment efficacy and discontinuation outcomes in teriflunomide (TFL) and dimethyl fumarate (DMF) in the treatment of relapsing-remitting multiple sclerosis (RRMS) in a real-world setting.

METHODS

We identified all patients starting TFL or DMF from the Danish Multiple Sclerosis Registry and compared on-treatment efficacy outcomes between DMF using TFL, adjusted for clinical baseline variables and propensity score-based methods.

RESULTS

We included 2,236 patients in the study: 1,469 patients on TFL and 767 on DMF. Annualized relapse rates (ARRs) in TFL and DMF were 0.16 (95% confidence interval [CI] 0.13-0.20) and 0.09 (95% CI 0.07-0.12), respectively. Relapse rate ratio for DMF/TFL was 0.58 (95% CI 0.46-0.73, p < 0.001). DMF had a higher relapse-free survival proportion at 48 months of follow-up (p < 0.05). We observed no difference in Expanded Disability Status Scale score worsening. Discontinuations due to disease breakthrough were 10.2% (95% CI 7.6%-12.8%) and 22.1% (95% CI 19.2%-25.0%) for DMF and TFL, respectively. A subgroup analysis of ARRs in 708 patients with available baseline MRI T2 lesion amount reported similar results after adjustment.

CONCLUSION

We found lower ARR, higher relapse-free survival, and lower incidence of discontinuation due to disease breakthrough on treatment with DMF compared with TFL.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that for patients with RRMS, DMF is more effective in preventing relapses and has lower discontinuation due to disease breakthrough compared with TFL.

A new way to estimate neurologic disease prevalence in the United States: Illustrated with MS

OBJECTIVE

Considerable gaps exist in knowledge regarding the prevalence of neurologic diseases, such as multiple sclerosis (MS), in the United States. Therefore, the MS Prevalence Working Group sought to review and evaluate alternative methods for obtaining a scientifically valid estimate of national MS prevalence in the current health care era.

METHODS

We carried out a strengths, weaknesses, opportunities, and threats (SWOT) analysis for 3 approaches to estimate MS prevalence: population-based MS registries, national probability health surveys, and analysis of administrative health claims databases. We reviewed MS prevalence studies conducted in the United States and critically examined possible methods for estimating national MS prevalence.

RESULTS

We developed a new 4-step approach for estimating MS prevalence in the United States. First, identify administrative health claim databases covering publicly and privately insured populations in the United States. Second, develop and validate a highly accurate MS case-finding algorithm that can be standardly applied in all databases. Third, apply a case definition algorithm to estimate MS prevalence in each population. Fourth, combine MS prevalence estimates into a single estimate of US prevalence, weighted according to the number of insured persons in each health insurance segment.

CONCLUSIONS

By addressing methodologic challenges and proposing a new approach for measuring the prevalence of MS in the United States, we hope that our work will benefit scientists who study neurologic and other chronic conditions for which national prevalence estimates do not exist.

The Italian multiple sclerosis register

The past decade has seen extraordinary increase in worldwide availability of and access to several large multiple sclerosis (MS) databases and registries. MS registries represent powerful tools to provide meaningful information on the burden, natural history, and long-term safety and effectiveness of treatments. Moreover, patients, physicians, industry, and policy makers have an active interest in real-world observational studies based on register data, as they have the potential to answer the questions that are most relevant to daily treatment decision-making. In 2014, the Italian MS Foundation, in collaboration with the Italian MS clinical centers, promoted and funded the creation of the Italian MS Register, a project in continuity with the existing Italian MS Database Network set up from 2001. Main objective of the Italian MS Register is to create an organized multicenter structure to collect data of all MS patients for better defining the disease epidemiology, improving quality of care, and promoting research projects in high-priority areas. The aim of this article is to present the current framework and network of the Italian MS register, including the methodology used to improve the quality of data collection and to facilitate the exchange of data and the collaboration among national and international groups.

Nationwide prevalence and incidence study of neuromyelitis optica spectrum disorder in Denmark

Objectives

To estimate the nationwide population-based incidence, prevalence, and geographical distribution of neuromyelitis optica (NMO) spectrum disorder (NMOSD) in Denmark based on the 2015 International Panel for NMO Diagnosis (IPND) criteria.

Methods

We conducted a multicentre, historically prospective study. Data were sourced from the Danish National Patient Registry, the Danish Multiple Sclerosis Registry, departments of neurology, and laboratories providing aquaporin-4 antibody test. Cases were selected based on the 2006 Wingerchuk and the 2015 IPND criteria and were individually validated by an expert panel.

Results

We confirmed NMO in 30 cases (2006 criteria) and NMOSD in 56 cases (2015 IPND criteria) between 2007 and 2014. Defined by the 2006 criteria, the incidence of NMO was 0.029 per 100,000 person-years (95% confidence interval [CI] 0.014–0.051), and the prevalence (aged 16 years and older) was 0.566 per 100,000 (95% CI 0.370–0.830). Based on the 2015 IPND criteria, the incidence of NMOSD was 0.070 per 100,000 person-years (95% CI 0.046–0.102), and the prevalence (aged 16 years and older) was 1.09 per 100,000 (95% CI 0.808–1.440), without regional differences.

Conclusions

Our estimates of incidence and prevalence are similar to other Caucasian population–based studies using the 2015 IPND criteria. We found no geographical clustering in Denmark.

Mental health among children of mothers with multiple sclerosis: A Danish cohort and register-based study

BACKGROUND

Multiple sclerosis is associated with an increased risk of developing physical, cognitive, and mental health problems. Current studies have demonstrated variating outcomes of parental multiple sclerosis mental health problems and their children's mental health development.

OBJECTIVE

The purpose of this study was to investigate whether maternal multiple sclerosis is associated with the mental health status of their child.

METHODS

Data from the Danish National Birth Cohort (DNBC) were merged with information from the Danish Multiple Sclerosis Registry. Two proxies, total difficulties score and prediction of any psychiatric diagnosis based on the strengths and difficulties questionnaire, were used to measure the mental health status of the children. The two groups were compared using Mann-Whitney and logistic regression analyses.

RESULTS

For the total difficulties score the control and exposed group consisted of respectively n = 42,016 and n = 40, and for the prediction of any psychiatric diagnosis respectively n = 16,829 and n = 17. We found no statistically significant association between maternal multiple sclerosis and mental health status on neither of the proxies.

CONCLUSION

Maternal multiple sclerosis did not show any association with the mental health status of their children at age eleven. On the contrary, other studies conclude that there is an association between maternal multiple sclerosis and the child's mental health status, one especially mediated by the maternal mental health status.

Early versus later treatment start in multiple sclerosis: a register-based cohort study

BACKGROUND AND PURPOSE

To assess long-term treatment effectiveness of disease-modifying therapy (DMT) initiated early in disease course versus later treatment start.

METHODS

We included all Danish patients with multiple sclerosis (MS) treated with DMT through two nationwide population-based MS registries. Patients were categorized as early treated if treatment started within 2 years after the first MS symptom (n = 2316) and later treated if treatment started between 2 and 8 years after clinical onset (n = 1479). We compared time from treatment start to progression to an Expanded Disability Status Scale (EDSS) score of 6 and mortality between cohorts as hazard ratio (HR) using a Cox proportional hazards model with adjustment for stabilized inverse probability of treatment weights. Several sensitivity analyses were conducted.

RESULTS

The median follow-up time of 3795 patients was 7.0 (range 0.6-19.5) years for the EDSS score of 6 outcome and 10.4 (range 1.2-20.1) years for the mortality outcome. Patients with later treatment start showed a 42% increased hazard rate of reaching an EDSS score of 6 compared with the early-treated patients [HR, 1.42; 95% confidence interval (CI), 1.18-1.70; P < 0.001]. When stratified by sex, the increased hazard among later-treated women persisted (HR, 1.53; 95% CI, 1.22-1.93; P < 0.001), whereas the HR was lower in men (1.25; 95% CI, 0.93-1.69; P = 0.15). Mortality was increased by 38% in later starters (HR, 1.38; 95% CI, 0.96-1.99; P = 0.08).

CONCLUSIONS

Patients who started treatment with DMT later reached an EDSS score of 6 more quickly compared with patients who started early and the delay showed a tendency to shorten time to death. Our results support the use of early treatment.

Infections seem to be more frequent before onset of pediatric multiple sclerosis: A Danish nationwide nested case–control study

Background:

Infections are suspected environmental triggers for multiple sclerosis (MS). The relationship between the timing and cumulative number of childhood infections regarding pediatric MS risk is uninvestigated.

Objectives:

To investigate whether childhood infections contribute to pediatric MS.

Methods:

A nationwide nested case–control study with detailed MS case ascertainment including chart review was undertaken. For each MS case, we selected five control children using density sampling from the entire Danish population, matching controls to children with MS by sex and birthdate. We analyzed data with the cumulative number of childhood infections as exposure and MS as outcome. Hazard ratios (HRs) including 95% confidence intervals (CIs) were estimated using Cox regression.

Results:

We identified 212 children with MS and 1,060 controls. Median age at MS onset was 15.3 years (range: 7.6–17.8 years); 72% were girls. Each infection during the preceding 3 years increased the hazard for MS by 11% (95% CI = 1.01–1.22, p = 0.04); having 5+ infections compared with 0–4 infections in the preceding 3 years doubled the hazard for MS (HR: 2.18; 95% CI = 1.12–4.30, p = 0.02).

Conclusion:

Children with MS appeared to have more infections in the 3 years preceding MS clinical onset; accordingly, immune response to infections may influence MS pathogenesis.

Pediatric acquired demyelinating syndromes: a nationwide validation study of the Danish National Patient Register

Objective

To validate the Danish National Patient Register’s (NPR) diagnoses of pediatric acquired demyelinating syndromes (ADS) including multiple sclerosis (MS).

Study design and setting

We identified ADS diagnostic groups using International Classification of Diseases (ICD) codes and reviewed medical records to validate the NPR diagnoses during 2008–2015.

Results

Among 409 children in the study, 184 children had a validated and final ADS diagnosis after reviewing medical records as follows: optic neuritis (ON; n=46), transverse myelitis (TM; n=16), acute disseminated encephalomyelitis (ADEM; n=50), clinically isolated syndrome (CIS) including dissemination in space (CIS [DIS]) but not dissemination in time (n=6), neuromyelitis optica spectrum disorder (NMOsd; n=5), and MS (n=61). During the mean follow-up of 4.6 years, 33% of children initially diagnosed with monophasic ADS progressed to MS. Positive predictive value (PPV) was 0.71 (95% confidence interval [CI] =0.62–0.80) for ON, 0.64 (95% CI =0.43–0.82) for TM, 0.93 (95% CI =0.84–0.98) for MS, 0.27 (95% CI =0.19–0.35) for CIS, 0.43 (95% CI =0.10–0.82) for NMOsd, and 0.15 (95% CI =0.10–0.20) for ADEM. Assuming complete coverage for non-MS ADS, the sensitivity was 0.99 (95% CI =0.93–1.00) for ON, 0.83 (95% CI =0.36–1.00) for CIS (DIS), and 0.80 (95% CI =0.56–0.94) for TM, but only 0.58 (95% CI =0.43–0.72) for ADEM and 0.60 (95% CI =0.15–0.95) for NMOsd.

Conclusion

PPV was high for MS and considered acceptable for ON and TM; therefore, these ICD revision 10 (ICD-10) codes from the NPR are useful for epidemiological studies. Conversely, PPV was low for CIS and ADEM; NMOsd was inconclusive.

Male factor infertility and risk of multiple sclerosis: A register-based cohort study

Background:

Gender, possibly due to the influence of gonadal hormones, is presumed to play a role in the pathogenesis of multiple sclerosis (MS), but no studies have evaluated whether male infertility is associated with MS.

Objective:

To study the association between male factor infertility and prevalent as well as incident MS.

Method:

Our cohort was established by linkage of the Danish National in vitro fertilization (IVF) registry to The Danish Multiple Sclerosis Registry and consisted of 51,063 men whose partners had undergone fertility treatment in all public and private fertility clinics in Denmark between 1994 and 2015.

Results:

With a median age of 34 years at baseline, 24,011 men were diagnosed with male factor infertility and 27,052 did not have male factor infertility and made up the reference group. Men diagnosed with male factor infertility had a higher risk of prevalent (odds ratio (OR) = 1.61, 95% confidence interval (95% CI) 1.04–2.51) and incident MS (hazard ratio (HR) = 1.28, 95% CI 0.76–2.17) when compared to the reference group.

Conclusion:

This nationwide cohort study has shown, for the first time, an association between male infertility and MS which may be due to underlying common etiologies such as hypogonadism, shared genetics, or a joint autoimmune component.

Causes of death in critically ill multiple sclerosis patients

BACKGROUND

Patients with multiple sclerosis (MS) experience higher mortality rates as compared to the general population. While the risk of intensive care unit (ICU) admission is also reported to be higher, little is known about causes of death CoD in critically ill MS patients.

AIM

To study the causes of death (CoD) in the series of critically ill patients with MS verified by autopsy.

METHODS

We reviewed hospital electronic charts of MS patients treated at the neurological ICU of a tertiary care hospital between 2000 and 2015. We compared clinical and pathological CoD for those who were autopsied.

RESULTS

Overall, 10 patients were identified (seven female; median age at death 65 years, range 27-80), and six of them were autopsied. The median MS duration prior to ICU admission was 27.5 years (range 1-50), and the median EDSS score at the time of ICU admission was 9 (range 5-9.5). The median length of ICU stay was 3 days (range 2-213). All the individuals in our series had experienced respiratory insufficiency during their ICU stay. The autopsy examination of brain tissue did not reveal evidences of MS lesions in one patient. In another patient, Lewy bodies were found on brain immunohistochemistry.

CONCLUSION

Mortality in critically ill MS patients is largely driven by respiratory complications. Sporadic disparities between clinical and pathological findings can be expected.

Comorbidity in multiple sclerosis is associated with diagnostic delays and increased mortality

OBJECTIVE

To investigate the effect of chronic comorbidity on the time of diagnosis of multiple sclerosis (MS) and on mortality in MS.

METHODS

We conducted a population-based, nationwide cohort study including all incident MS cases in Denmark with first MS symptom between 1980 and 2005. To investigate the time of diagnosis, we compared individuals with and without chronic comorbidity using multinomial logistic regression. To investigate mortality, we used Cox regression with time-dependent covariates, following study participants from clinical MS onset until endpoint (death) or to the end of the study, censuring at emigration.

RESULTS

We identified 8,947 individuals with clinical onset of MS between 1980 and 2005. In the study of time of diagnosis, we found statistically significant odds ratios for longer diagnostic delays with cerebrovascular comorbidity (2.01 [1.44-2.80]; <0.0005), cardiovascular comorbidity (4.04 [2.78-5.87]; <0.0005), lung comorbidity (1.93 [1.42-2.62]; <0.0005), diabetes comorbidity (1.78 [1.04-3.06]; 0.035), and cancer comorbidity (2.10 [1.20-3.67]; 0.009). In the mortality study, we found higher hazard ratios with psychiatric comorbidity (2.42 [1.67-3.01]; <0.0005), cerebrovascular comorbidity (2.47 [2.05-2.79]; <0.0005), cardiovascular comorbidity (1.68 [1.39-2.03]; <0.0005), lung comorbidity (1.23 [1.01-1.50]; 0.036), diabetes comorbidity (1.39 [1.05-1.85]; 0.021), cancer comorbidity (3.51 [2.94-4.19]; <0.0005), and Parkinson disease comorbidity (2.85 [1.34-6.06]; 0.007).

CONCLUSIONS

An increased awareness of both the necessity of neurologic evaluation of new neurologic symptoms in persons with preexisting chronic disease and of optimum treatment of comorbidity in MS is critical.

Pediatric-onset multiple sclerosis and other acquired demyelinating syndromes of the central nervous system in Denmark during 1977-2015: A nationwide population-based incidence study

BACKGROUND

The incidence of acquired demyelinating syndromes (ADS) including multiple sclerosis (MS) has never been investigated in a Danish pediatric population.

OBJECTIVES

We estimated the nationwide age- and sex-specific incidence of pediatric ADS including MS.

METHODS

Data were sourced from the Danish Multiple Sclerosis Registry, providing cases of pediatric MS for 1977-2015, and the National Patient Register, providing cases of ADS during 2008-2015. All medical records were reviewed to validate the register-based diagnoses.

RESULTS

We identified 364 cases of pediatric MS occurring during 1977-2015 (incidence rate = 0.79 per 100,000 person-years). MS was exceptionally rare before puberty, but the incidence rose considerably from 9 years in girls and 11 years in boys. The female-to-male ratio was 2.5; the median age at onset was 16 years (range = 7-17 years). The MS incidence rate was relatively stable through the study period. During 2008-2015, we identified 219 ADS cases. The incidence was 2.29 per 100,000 person-years with considerable differences in the age peaks for the separate ADS.

CONCLUSION

The incidence rates of MS and other ADS in Denmark were higher than those reported for some other European countries. Referral bias and classification differences may account for this disparity, in particular the age-intervals and the definition of onset.

Age at Menarche and Risk of Multiple Sclerosis: A Prospective Cohort Study Based on the Danish National Birth Cohort

Few studies have addressed the possible association between age at menarche and multiple sclerosis (MS), and results are conflicting. We studied this issue in a large prospective cohort study. The study cohort comprised 77,330 women included in the Danish National Birth Cohort (1996-2002). Information on menarcheal age was ascertained at the first interview, which took place in the 16th week of pregnancy. Women were followed for MS from the first interview to December 31, 2011. Associations between age at menarche and risk of MS were evaluated with hazard ratios and 95% confidence intervals using Cox proportional hazards regression models. Overall, 226 women developed MS during an average follow-up period of 11.7 years. Age at menarche among women with MS was generally lower than that among women without MS (Wilcoxon rank-sum test; P = 0.002). We observed an inverse association between age at menarche and MS risk. For each 1-year increase in age at menarche, risk of MS was reduced by 13% (hazard ratio = 0.87, 95% confidence interval: 0.79, 0.96). Early age at menarche appears to be associated with an increased risk of MS. The mechanisms behind this association remain to be established.

Symptomatic treatment in multiple sclerosis-interim analysis of a nationwide registry

OBJECTIVE

To analyze symptomatic treatment in patients with multiple sclerosis (MS).

BACKGROUND

Multiple sclerosis is a chronic inflammatory disease of the central nervous system, with accumulating disability symptoms like spasticity, voiding disorders, depression, and pain might occur.

MATERIAL AND METHODS

The nationwide German MS registry was initiated 2001 under guidance of the German MS society (Deutsche MS Gesellschaft). This study was performed as an interim analysis to lay foundation for future work on this topic. A subcohort of 5113 patients was assessed for this interim analysis. The mean age of the patients was 45.3 years; mean EDSS was 4.2. More than two-third of the enrolled patients were females (70.9%).

RESULTS

Most frequent symptoms were fatigue (60%), followed by spasticity (52.5%) and voiding disorders (51.7%). The likelihood of treatment was highest for epileptic disorders (68.8%), spasticity (68.5%), pain (60.7%), and depression (58.9%). Multivariate regression analysis showed that retirement was the strongest factor predictive for antispastic treatment (β=.061, P=.005).

CONCLUSION

Almost all patients in this analysis suffer from symptoms due to advanced MS. Treatment for the various symptoms differed tremendously. The likelihood of treatment correlated with the availability of effective therapeutic agents. Clinicians should put more awareness on MS symptoms. Symptomatic treatment may improve quality of life.

The impact of quality of life on treatment preferences in multiple sclerosis patients

INTRODUCTION

Multiple sclerosis (MS) is a demyelinating disorder with an unpredictable and often disabling course. MS symptoms are very heterogeneous and may lead to reduced physical, cognitive, and psychosocial functioning decreasing patients' quality of life (QoL). Today, various disease-modifying treatments (DMTs) may prevent disease progression. However, it is increasingly complex to select the right therapy for a given patient and patient preferences should be considered when making treatment decisions. This study aimed to explore the main factors affecting patients' preferences regarding MS treatment and health care.

METHODS

Five qualitative focus group interviews were carried out with a total of 40 participants from across Denmark. A semistructured question guide included questions that were identified in a systematic literature study about QoL and treatment preferences in patients with MS. The participants were asked to describe their disease experiences, their health-related QoL, and reasons behind their preferences with regard to treatment and care. The data were analyzed using content analysis and a constructivist approach.

RESULTS

The participants' physical, cognitive, and psychosocial QoL and functioning were reduced by disease symptoms, treatment side effects, and mode of administration. Their ability to uphold meaningful role functioning was crucial to their treatment priorities. The preeminence of anticipated efficacy, ie, the patients' hope that DMT might prevent disease deterioration in the future, was modified by their present QoL and functioning when ultimately framing their treatment preferences. There was an unmet information and support need from neurology clinics, particularly at the time of diagnosis.

CONCLUSION

The participants' treatment preferences were influenced by a matrix of treatment and QoL-related factors and evolved with time and along with personal and professional changes in life. The patients preferred to receive a clear recommendation of DMT from the neurologist taking into account their individual functioning and present QoL priorities.

Inverse comorbidity in multiple sclerosis: Findings in a complete nationwide cohort

BACKGROUND

Inverse comorbidity is disease occurring at lower rates than expected among persons with a given index disease. The objective was to identify inverse comorbidity in MS.

METHODS

We performed a combined case-control and cohort study in a total nationwide cohort of cases with clinical onset of MS 1980-2005. We randomly matched each MS-case with five population controls. Comorbidity data were obtained from multiple, independent nationwide registries. Cases and controls were followed from January 1977 to the index date, and from the index date through December 2012. We controlled for false discovery rate and investigated each of eight pre-specified comorbidity categories: psychiatric, cerebrovascular, cardiovascular, lung, and autoimmune comorbidities, diabetes, cancer, and Parkinson's disease.

RESULTS

A total of 8947 MS-cases and 44,735 controls were eligible for inclusion. We found no inverse associations with MS before the index date. After the index date, we found a decreased occurrence of chronic lung disease (asthma and chronic obstructive pulmonary disease) (HR 0.80 (95% CI 0.75-0.86, p<0.00025)) and overall cancer (HR 0.88 (95% CI 0.81-0.95, p=0.0005)) among MS-cases.

CONCLUSION

This study showed a decreased risk of cancers and pulmonary diseases after onset of MS. Identification of inverse comorbidity and of its underlying mechanisms may provide important new entry points into the understanding of MS.

The Danish Multiple Sclerosis Treatment Register

AIM OF THE DATABASE

The Danish Multiple Sclerosis Treatment Register (DMSTR) serves as a clinical quality register, enabling the health authorities to monitor the quality of the disease-modifying treatment, and it is an important data source for epidemiological research.

STUDY POPULATION

The DMSTR includes all patients with multiple sclerosis who had been treated with disease-modifying drugs since 1996. At present, more than 8,400 patients have been registered in this database. Data are continuously entered online into a central database from all sites in Denmark at start and at regular visits.

MAIN VARIABLES

Include age, sex, onset year and year of the diagnosis, basic clinical information, and information about treatment, side effects, and relapses.

DESCRIPTIVE DATA

Notification is done at treatment start, and thereafter at every scheduled clinical visit 3 months after treatment start, and thereafter every 6 months. The longitudinally collected information about the disease activity and side effects made it possible to investigate the clinical efficacy and adverse events of different disease-modifying therapies.

CONCLUSION

The database contributed to a certain harmonization of treatment procedures in Denmark and will continue to be a major factor in terms of quality in clinical praxis, research and monitoring of adverse events, and plays an important role in research.

Employment, disability pension and income for children with parental multiple sclerosis

Background:

Little is known about the consequences of parental multiple sclerosis (MS) on offspring’s socioeconomic circumstances.

Objective:

To investigate employment, disability pension and income in offspring of parents with MS compared with matched reference persons in a nationwide register-based cohort study.

Methods:

All Danish-born persons with onset of MS during 1950–1986 were retrieved from the Danish Multiple Sclerosis Registry. Their offspring were identified using the Civil Registration System. One random offspring from each sibship was matched by sex and year of birth with eight random reference persons.

Results:

We included 2456 MS offspring and 19,648 reference persons. At age 30, employment was lower among MS offspring than reference children (odds ratio (OR): 0.89; 95% confidence interval (CI): 0.84–0.95; p = 0.0003), and they more often received disability pension (OR: 1.31; 95% CI: 1.15–1.50; p < 0.0001) at ages 30 and 40 but not at age 50. Although the mean income was not significantly lower for the MS offspring cohort, most of them attained an annual personal income below 250,000 DKK (Danish krone), that is, ~33,650 EUR (OR: 0.91; 95% CI: 0.84–0.99; p = 0.04).

Conclusion:

Having had a parent with MS may affect employment and increase the risk of disability pension and low income in adult life.

Educational achievements of children of parents with multiple sclerosis: A nationwide register-based cohort study

Little is known about the impact of parental multiple sclerosis (MS) on offspring's educational attainment. The objective of the study was to examine educational achievements in offspring of parents with MS compared with matched children of parents without MS in a nationwide register-based cohort study. Children of all Danish-born residents with onset between 1950 and 1986 were identified by linking the Danish Multiple Sclerosis Registry with the Civil Registration System. Twins, children with MS, and emigrated persons were excluded. The reference cohort consisted of randomly drawn individuals from the Civil Registration System without parental MS matched 8:1 to the MS offspring by sex and year of birth. Information about education was linked to the cohorts from nationwide educational registries. We included 4177 children of MS parents and 33,416 reference persons. Children of MS parents achieved statistically significant higher average grades than the reference cohort in their final exam of basic school with a mean grade difference of 0.46 (95 % CI 0.22-0.69; p = 0.0002). We found no difference in achievement of educational level above basic school (OR 1.04; 95 % CI 0.98-1.10; p = 0.20). There was a trend toward more MS offspring attaining health-related educations (OR 1.10; 95 % CI 1.00-1.21; p = 0.06). In conclusion, children of MS parents showed a small advantage in grade point average in final examinations in basic school, and they more often tended toward health-related educations. This study revealed no negative consequences of parental MS on grades and highest educational level achieved.

Shift work at young age is associated with increased risk of multiple sclerosis in a Danish population

BACKGROUND

Epidemiological studies suggest an important role for environmental factors in developing multiple sclerosis (MS). Furthermore several studies have indicated that the effect of environmental factors may be especially pronounced in adolescents. Recently only one study investigated and found that shift work at young age is associated with an increased risk of developing MS. In this study we focused on the effect of shift work in the vulnerable period between 15-19 years.

OBJECTIVE

The aim of this study was to investigate the association between shift work at young age and the risk of developing MS.

METHODS

We performed a large case-control study including 1723 patients diagnosed with MS and 4067 controls. MS patients were recruited from the Danish Multiple Sclerosis Biobank and controls from The Danish Blood Donor Study. Information on working patterns and lifestyle factors was obtained using a comprehensive lifestyle-environmental factor questionnaire with participants enrolled between 2009 and 2014. Logistic regression models were used to investigate the association between shift work at age 15-19 years and the subsequent risk of MS and were controlled for effects due to established MS risk factors.

RESULTS

We found a statistically significant association when total numbers of night shifts were compared with non-shift workers. For every additional 100 night shifts the odds ratio (OR) for MS was 1.20 (95% confidence interval (CI), 1.08-1.34, p=0.001). Increasing intensity of shift work also increased MS risk. For every additional night per month the OR was 1.04 (95% CI, 1.01-1.06, p=0.002). Duration of shift work in years was not associated with risk of MS.

CONCLUSION

This study supports a statistically significant association between shift work at age 15-19 years and MS risk.

Self-rated health in women prior to clinical onset of multiple sclerosis: A study within the Danish National Birth Cohort

BACKGROUND

It has been suggested that onset of multiple sclerosis (MS) is preceded by a clinically silent period of up to 10 years.

OBJECTIVES

Examine whether such a period should be associated with poor self-rated health (SRH).

METHODS

Information on SRH before pregnancy was ascertained among 80,848 women participating in the Danish National Birth Cohort (DNBC) 1996-2002. Women were followed for MS from enrolment in DNBC in the 16th week of pregnancy until 31 December 2011. Associations between SRH and MS were evaluated by means of hazard ratios (HR) with 95% confidence intervals (CIs) using Cox proportional hazard models.

RESULTS

During on average 11.7 years of follow-up, 239 women were diagnosed with MS. Overall, neither women with fair (HR = 1.09 (95% CI = 0.83-1.41), n = 113) nor poor pre-pregnancy SRH (HR = 0.94 (95% CI = 0.47-1.87), n = 9) were at an increased risk of MS compared with women reporting very good pre-pregnancy SRH. Supplementary analyses showed no significant differences in MS risk in consecutive periods of follow-up.

CONCLUSION

In this first prospective cohort study assessing MS risk as a function of SRH, we found no indication of a long period of poor SRH prior to MS. Our findings based on pregnant women may not necessarily apply to all women.