Disability trajectories by progression independent of relapse activity status differ in pediatric, adult and late-onset multiple sclerosis

BACKGROUND

To compare Expanded Disability Status Scale (EDSS) trajectories over time between Multiple Sclerosis (MS) groups with pediatric (POMS), adult (AOMS) and late (LOMS) onset, and between patients with and without progression independent of relapse activity (PIRA).

METHODS

Patients with a first visit within 1 year from onset, ≥ 5-year follow-up and ≥ 1 visit every 6 months were selected from the Italian MS Register. Adjusted disability trajectories were assessed by longitudinal models for repeated measures. Comparisons between groups and between patients with and without PIRA in subgroups were performed by evaluating the yearly differences of mean EDSS score changes versus baseline (delta-EDSS). A first CDA event was defined as a 6-months confirmed disability increase from study baseline, measured by EDSS (increase ≥ 1.5 points with baseline EDSS = 0; ≥ 1.0 with baseline EDSS score ≤ 5.0 and ≥ 0.5 point with baseline EDSS > 5.5). PIRA was defined as a CDA event occurring more than 90 days after and more than 30 days before the onset of a relapse.

RESULTS

3777 MS patients (268 POMS, 3282 AOMS, 227 LOMS) were included. The slope of disability trajectories significantly diverged in AOMS vs POMS starting from the second year of follow-up (Year 2: delta2-EDSS 0.18 (0.05; 0.31), p = 0.0054) and then mean delta2-EDSS gradually increased up to 0.23 (0.07; 0.39, p = 0.004) at year 5. Patients with PIRA had significant (p < 0.0001) steeper increase in EDSS scores than those without PIRA in all groups, although in POMS, the disability trajectories began to diverge later and at a lesser extent with delta-EDSS score of 0.48 vs 0.83 in AOMS and 1.57 in LOMS, at 3 years after the first PIRA.

CONCLUSIONS

Age is relevant in determining disability progression in MS. POMS shows a less steep increase in EDSS scores over time than older patients. The effect of PIRA in accelerating EDSS progression is less pronounced in POMS than in AOMS and LOMS.

Mobility trajectories in multiple sclerosis: A comparative study of timed 25-foot walk and a patient-reported outcome measure

BACKGROUND

Loss of mobility is common in persons with multiple sclerosis (PwMS), but little is known about this impairment from the patient's perspective.

OBJECTIVE

The aim is to model longitudinal variation in a mobility patient-reported outcome (PRO) and compare trajectories to those observed for Timed 25-Foot Walk (T25FW) in a retrospective cohort.

METHODS

Latent-class growth analysis was applied to 47,508 measures of Performance Scales© Mobility PRO (PS-Mobility) over ~4 years for 8524 PwMS. For 7347 PwMS, there were 41,988 T25FW measures during this period. Repeated measures correlation and concordance of trajectory assignment were evaluated.

RESULTS

At the group level, PS-Mobility and T25FW linearly worsened and repeated-measures correlation was moderate. Eight latent classes with varying shapes that worsened described PS-Mobility variation, compared to six latent classes for T25FW that differed by intercept. The agreement between PS-Mobility and T25FW cluster assignment was modest. A higher proportion of individuals who were Black/African American, older, Medicaid beneficiaries, living in deprived neighborhoods, had longer disease duration, had progressive disease, and ever smokers were assigned to more impaired clusters.

DISCUSSION

Cross-sectionally, PS-Mobility and T25FW were highly correlated, but longitudinally correlation was modest to moderate, underscoring the importance of considering both objective and subjective perspectives in evaluating mobility changes in PwMS.

Long-term disability trajectories in multiple sclerosis: a group-based trajectory analysis of the AusLong cohort

BACKGROUND

Previous natural history studies highlighted a consistent heterogeneity of disability trajectories among individuals with primary or secondary progressive multiple sclerosis (MS). However, evidence on disability progression in relapsing onset MS is scarce.The aim of this study was to investigate heterogeneity in disability accumulation over 10 years following a first clinical diagnosis of central nervous system demyelination (FCD) and identify genetic, demographic, environmental and clinical factors associated with these trajectories.

METHODS

We used group-based trajectory models to measure heterogeneity in disability trajectories based on the Expanded Disability Status Scale (EDSS) in a prospectively assessed cohort of 263 participants. To capture sustained neurological impairments and avoid issues related to significant changes in EDSS associated with relapse, we did not consider EDSS points recorded within 3 months of a relapse.

RESULTS

We identified three distinct and clinically meaningful disability trajectories: No/minimal, moderate and severe. Those in the no/minimal disability trajectory showed no appreciable progression of disability (median EDSS∼1 at 10-year review) while those in the moderate and severe disability trajectories experienced disability worsening (median time to reach EDSS 4 was 9 and 7 years, respectively). Compared with the no/minimal disability trajectory, those with older age, a higher number of relapses within the first 5 years post-FCD, and a higher number of comorbidities at baseline were more likely to be in the worse disability trajectory. Surprisingly, baseline MRI and anatomical site of initial symptoms did not influence long-term outcomes.

CONCLUSIONS

Those at higher risk of faster MS disability progression can be identified based on their early clinical characteristics with potential therapeutic implications for early intervention and treatment escalation.

Factors associated with trajectories of bone marrow lesions over 4 years: data from the Osteoarthritis Initiative

OBJECTIVE

To identify bone marrow lesion (BML) trajectories over 4 years and their demographic and structural predictors in middle-aged and older adults with or at increased risk of knee osteoarthritis (OA).

METHODS

A total of 614 participants (mean age 61 years, 62% female) from the Osteoarthritis Initiative cohort (OAI) were included. BMLs in 15 anatomical locations of the knee were measured annually from baseline to 4 years using the Magnetic Resonance Imaging Osteoarthritis Knee Score (MOAKS) method. BML trajectories were determined using latent class mixed models (LCMMs). Multinomial logistic regression was used to examine baseline characteristics that predicted BML trajectories.

RESULTS

Three distinct BML trajectories were identified: "Mild-stable BMLs" (25.9%), "Moderate-stable BMLs" (66.4%), and "Rapid-rise BMLs" (7.7%). Compared to the "Mild-stable BMLs" trajectory, current smokers were more likely to be in the "Moderate-stable BMLs" (odds ratio [OR] 2.089, P < 0.001) and "Rapid-rise" (OR 2.462, P < 0.001) trajectories. Moreover, female sex and meniscal tears were associated with an increased risk of being in the "Rapid-rise BMLs" trajectory (OR 2.023 to 2.504, P < 0.05). Participants who had higher education levels and drank more alcohol were more likely to be in the "Rapid-rise BMLs" trajectory (OR 1.624 to 3.178, P < 0.05) and less likely to be in the "Moderate-stable BMLs" trajectory (OR 0.668 to 0.674, P < 0.05).

CONCLUSIONS

During the 4-year follow-up, most participants had relatively stable BMLs, few had enlarged BMLs, and no trajectory of decreased BMLs was identified. Sociodemographic factors, lifestyle, and knee structural pathology play roles in predicting distinct BML trajectories.

Diet and omega-3 and vitamin D supplement use predict five-year fatigue and disability trajectories in people with multiple sclerosis

BACKGROUND

Fatigue and disability are indicators of disease progression experienced by many people with multiple sclerosis (pwMS). Understanding trajectories of these outcomes, and their predictors, may provide insight to potential interventions for MS management.

METHODS

Survey data from 839 pwMS from the Health Outcomes and Lifestyle in pwMS study were analysed. Fatigue was defined as mean Fatigue Severity Scale >5, and severe disability as Patient Determined Disease Steps >5. Group-based trajectory modelling was used to identify fatigue and disability trajectories over five-years. Dietary predictors associated with outcome trajectory group membership were assessed using log-binomial regression. Demographic and clinical characteristics were considered in multivariable models.

RESULTS

Distinct trajectories for fatigue and disability were identified. For fatigue, 58 % of pwMS were assigned to low-, and 42 % to high-, fatigue trajectory groups. For disability, 85 % of pwMS were assigned to low-, and 15 % to high-, disability groups. Baseline high-quality diet, and omega-3 and vitamin D supplement use, were associated with reduced risk of being in high-fatigue and high-disability trajectories, while meat and dairy consumption were associated with increased risk.

CONCLUSIONS

A high-quality diet, avoiding meat and dairy, and omega-3 and vitamin D supplement use, individually predict better fatigue and disability trajectories. Dietary modifications should be considered in MS management.

Late-onset multiple sclerosis: disability trajectories in relapsing-remitting patients of the Italian MS Registry

BACKGROUND

Generally infrequent, multiple sclerosis (MS) with late onset (LOMS) is characterized by an onset over the age of 50 and a mainly progressive course, while relapsing-remitting (RR) forms are less frequently observed and explored. This study aimed to characterize a large cohort of MS patients with RRMS at onset to assess the baseline factors related to the worst disability trajectories and explore the role of LOMS.

METHODS

The data were extracted from the Italian MS Register (IMSR). Disability trajectories, defined using at least two and up to twenty expanded disability status scale (EDSS) assessments annually performed, were implemented using group-based trajectory models (GBTMs) to identify different groups with the same trajectories over time. MS profiles were explored using multinomial logistic regression.

RESULTS

A total of 16,159 RR patients [1012 (6.26%) presented with LOMS] were analyzed. The GBTM identified four disability trajectories. The group with the most severe EDSS trend included 12.3% of the patients with a mean EDSS score > 4, which increased over time and exceeded 6 score. The group with medium severity EDSS trend comprised 21.9% of the patients and showed a change in EDSS > 3 scores over time. The largest group with 50.8% of patients reported a constant EDSS of 2 score. Finally, the benign group comprised 14.9% of the patients with a low and constant EDSS of 1 score over time. The probability of being in the worst groups increased if the patient was male; had LOMS or experienced brainstem, spinal, or supratentorial symptoms.

CONCLUSIONS

Four MS severity profiles among RRMS patients in the IMSR have been reported, with LOMS being associated with a rapid worsening of EDSS scores. These findings have important implications for recognizing and managing how older age, aging, and age-related factors interact with MS and its evolution.

Clinical impact of gender and age at onset on disease trajectory in primary progressive multiple sclerosis patients

BACKGROUND AND OBJECTIVES

Primary-progressive multiple sclerosis (PPMS) is characterized by gradual neurological deterioration without relapses. This study aimed to investigate the clinical impact of gender and age at disease onset on disease progression and disability accumulation in patients with this disease phenotype.

METHODS

Secondary data from the RelevarEM registry, a longitudinal database in Argentina, were analyzed. The cohort comprised patients with PPMS who met inclusion criteria. Statistical analysis with multilevel Bayesian robust regression modeling was conducted to assess the associations between gender, age at onset, and Expanded Disability Status Scale (EDSS) score trajectories.

RESULTS

We identified 125 patients with a confirmed diagnosis of PPMS encompassing a total of 464 observations. We found no significant differences in EDSS scores after 10 years of disease progression between genders (-0.08; credible interval (CI): -0.60, 0.42). A 20-year difference in age at onset did not show significant differences in EDSS score after 10 years of disease progression (0.281; CI: -0.251, 0.814). Finally, we also did not find any clinically relevant difference between gender EDSS score with a difference of 20 years in age at onset (-0.021; CI: -0.371, 0.319).

CONCLUSION

Biological plausibility of gender and age effects does not correlate with clinical impact measured by EDSS score.

Consensus recommendations for diagnosis and treatment of Multiple Sclerosis: 2023 revision of the MENACTRIMS guidelines

With evolving diagnostic criteria and the advent of new oral and parenteral therapies for Multiple Sclerosis (MS), most current diagnostic and treatment algorithms need revision and updating. The diagnosis of MS relies on incorporating clinical and paraclinical findings to prove dissemination in space and time and exclude alternative diseases that can explain the findings at hand. The differential diagnostic workup should be guided by clinical and laboratory red flags to avoid unnecessary tests. Appropriate selection of MS therapies is critical to maximize patient benefit. The current guidelines review the current diagnostic criteria for MS and the scientific evidence supporting treatment of acute relapses, radiologically isolated syndrome, clinically isolated syndrome, relapsing remitting MS, progressive MS, pediatric cases and pregnant women. The purpose of these guidelines is to provide practical recommendations and algorithms for the diagnosis and treatment of MS based on current scientific evidence and clinical experience.

A mixture model for differentiating longitudinal courses of multiple sclerosis

BACKGROUND

Multiple sclerosis has a broad spectrum of clinical courses. Early identification of patients at greater risk of accumulating disability is essential.

OBJECTIVES

Identify groups of patients with similar presentation through a mixture model and predict their trajectories over the years.

METHODS

Retrospective study of patients from 1994 to 2019. We performed a latent profile analysis followed by a latent transition analysis based on eight parameters: age, disease duration, EDSS, number of relapses, multi-topographic symptoms, motor impairment, sphincter impairment, and infratentorial lesions.

RESULTS

We included 629 patients, regardless of the phenotypical classification. We identified three distinct groups at the beginning and end of the follow-up. The three-classes model disclosed the "No disability regardless disease duration" (NDRDD) class with low EDSS and younger patients, the "Disability within a short disease duration" (DSDD) class with the worse disability besides short illness, and the "Disability within a long disease duration" (DLDD) class that achieved high EDSS over a long disease duration. EDSS, disease duration, and no sphincter impairment had the best entropy to distinguish classes at the initial presentation. Over time, the patients from NDRDD had a 52.1 % probability of changing to DLDD and 7.7 % of changing to DSDD.

CONCLUSIONS

We identified three groups of clinical presentations and their evolution over time based on considered prognostic factors. The most likely transition is from NDRDD to DLDD.

Measuring disability in multiple sclerosis: the WHODAS 2.0

INTRODUCTION

Reliable measurement of disability in multiple sclerosis (MS) using a comprehensive, patient self-reported scale, such as the World Health Organization Disability Assessment Schedule (WHODAS) 2.0, would be of clinical and research benefit.

METHODS

In the Trajectories of Outcome in Neurological Conditions-MS study, WHODAS 2.0 (WHODAS-36 items for working, WHODAS-32 items if not working, WHODAS-12 items short-form) was examined using Rasch analysis in 5809 people with MS.

RESULTS

The 36- and 32-item parallel forms, and the cognitive and physical domains, showed reliability consistent with individual or group use. The 12-item short-form is valid for group use only. Interval level measurement for parametric statistics can be derived from all three scales which showed medium to strong effect sizes for discrimination across characteristics such as age, subtype, and disease duration. Smallest detectable difference for each scale was < 6 on the standardised metric of 0-100 so < 6% of the total range. There was no substantial differential item functioning (DIF) by age, gender, education, working full/part-time, or disease duration; the finding of no DIF for time or sample supports the use of WHODAS 2.0 for longitudinal studies, with the 36- and 32-item versions and the physical and cognitive domains valid for individual patient follow-up.

CONCLUSIONS

Disability in MS can be comprehensively measured at interval level by the WHODAS 2.0, and validly monitored over time. Routine use of this self-reported measure in clinical and research practice would give valuable information on the trajectories of disability of individuals and groups.

Progression risk stratification with six-minute walk gait speed trajectory in multiple sclerosis

Background

Multiple Sclerosis (MS) disease progression has notable heterogeneity among patients and over time. There is no available single method to predict the risk of progression, which represents a significant and unmet need in MS.

Methods

MS and healthy control (HC) participants were recruited for a 2-year observational study. A latent-variable growth mixture model (GMM) was applied to cluster baseline 6-min walk gait speed trajectories (6MWGST). MS patients within different 6 MWGST clusters were identified and stratified. The group membership of these MS patients was compared against 2-year confirmed-disease progression (CDP). Clinical and patient-reported outcome (PRO) measures were compared between HC and MS subgroups over 2 years.

Results

62 MS and 41 HC participants completed the 2-year study. Within the MS cohort, 90% were relapsing MS. Two distinct patterns of baseline 6 MWGST emerged, with one cluster displaying a faster gait speed and a typical "U" shape, and the other showing a slower gait speed and a "flattened" 6 MWGST curve. We stratified MS participants in each cluster as low- and high-risk progressors (LRP and HRP, respectively). When compared against 2-year CDP, our 6 MWGST approach had 71% accuracy and 60% positive predictive value. Compared to the LRP group, those MS participants stratified as HRP (15 out of 62 MS participants), were on average 3.8 years older, had longer MS disease duration and poorer baseline performance on clinical outcomes and PROs scores. Over the subsequent 2 years, only the HRP subgroup showed a significant worsened performance on 6 MW, clinical measures and PROs from baseline.

Conclusion

Baseline 6 MWGST was useful for stratifying MS participants with high or low risks for progression over the subsequent 2 years. Findings represent the first reported single measure to predict MS disease progression with important potential applications in both clinical trials and care in MS.

Long-term trajectories of ambulatory impairment in multiple sclerosis

BACKGROUND

Ambulatory impairment is a common and complex manifestation of multiple sclerosis (MS), and longitudinal patterns are not well understood.

OBJECTIVE

To characterize longitudinal walking speed trajectories in a general MS patient population and in those with early disease (⩽ 5 years from onset), identify subgroups with similar patterns, and examine associations with individual attributes.

METHODS

Using a retrospective cohort study design, latent class growth analysis was applied to longitudinal timed 25-foot walk (T25-FW) data from 7683 MS patients, to determine T25-FW trajectories. Associations were evaluated between trajectory assignment and individual attributes. Analyses were repeated for 2591 patients with early disease.

RESULTS

In the general patient population, six trajectories were discerned, ranging from very minimal to very high impairment at baseline, with variability in impairment accrual. The clusters with moderate to very high walking impairment were associated with being female, older and Black American, longer symptom duration, progressive course, and depressive symptoms. In the early disease subset, eight trajectories were discerned that included two subgroups that rapidly accrued impairment.

CONCLUSION

We identified novel subgroups of MS patients will distinct long-term T25-FW trajectories. These results underscore that socially disadvantaged and economically marginalized MS patients are the most vulnerable for severe ambulatory impairment.

The natural history of primary progressive multiple sclerosis: insights from the German NeuroTransData registry

BACKGROUND

Primary progressive multiple sclerosis (PPMS) is characterised by gradual worsening of disability from symptom onset. Knowledge about the natural course of PPMS remains limited.

METHODS

PPMS patients from the German NeuroTransData (NTD) MS registry with data from 56 outpatient practices were employed for retrospective cross-sectional and longitudinal analyses. The cross-sectional analysis included a contemporary PPMS cohort with a documented visit within the last 2 years before index date (1 Jan 2021). The longitudinal analysis included a disease modifying therapy (DMT)-naïve population and focused on the evolution of expanded disability status scale (EDSS) from the first available assessment at or after diagnosis within the NTD registry to index date. Outcome measures were estimated median time from first EDSS assessment to first 24-week confirmed EDSS ≥ 4 and ≥ 7. Besides EDSS change, the proportion of patients on disability pension were described over time.

RESULTS

The cross-sectional analysis included 481 PPMS patients (59.9% female, mean [standard deviation, SD] age 60.5 [11.5] years, mean [SD] EDSS 4.9 [2.1]). Estimated median time from first EDSS assessment after diagnosis to reach 24-week confirmed EDSS ≥ 4 for DMT-naïve patients was 6.9 years. Median time to EDSS ≥ 7 was 9.7 years for 25% of the population. Over a decade mean (SD) EDSS scores increased from 4.6 (2.1) to 5.7 (2.0); the proportion of patients on disability pension increased from 18.9% to 33.3%.

CONCLUSIONS

This study provides first insights into the German NTD real-world cohort of PPMS patients. Findings confirm the steadily deteriorating course of PPMS accompanied by increasingly limited quality of life.

Heterogeneity on long-term disability trajectories in patients with secondary progressive MS: a latent class analysis from Big MS Data network

BACKGROUND

Over the decades, several natural history studies on patients with primary (PPMS) or secondary progressive multiple sclerosis (SPMS) were reported from international registries. In PPMS, a consistent heterogeneity on long-term disability trajectories was demonstrated. The aim of this study was to identify subgroups of patients with SPMS with similar longitudinal trajectories of disability over time.

METHODS

All patients with MS collected within Big MS registries who received an SPMS diagnosis from physicians (cohort 1) or satisfied the Lorscheider criteria (cohort 2) were considered. Longitudinal Expanded Disability Status Scale (EDSS) scores were modelled by a latent class growth analysis (LCGA), using a non-linear function of time from the first EDSS visit in the range 3-4.

RESULTS

A total of 3613 patients with SPMS were included in the cohort 1. LCGA detected three different subgroups of patients with a mild (n=1297; 35.9%), a moderate (n=1936; 53.6%) and a severe (n=380; 10.5%) disability trajectory. Median time to EDSS 6 was 12.1, 5.0 and 1.7 years, for the three groups, respectively; the probability to reach EDSS 6 at 8 years was 14.4%, 78.4% and 98.3%, respectively. Similar results were found among 7613 patients satisfying the Lorscheider criteria.

CONCLUSIONS

Contrary to previous interpretations, patients with SPMS progress at greatly different rates. Our identification of distinct trajectories can guide better patient selection in future phase 3 SPMS clinical trials. Additionally, distinct trajectories could reflect heterogeneous pathological mechanisms of progression.

Does group-based trajectory modeling estimate spurious trajectories?

BACKGROUND

Group-based trajectory modelling (GBTM) is increasingly used to identify subgroups of individuals with similar patterns. In this paper, we use simulated and real-life data to illustrate that GBTM is susceptible to generating spurious findings in some circumstances.

METHODS

Six plausible scenarios, two of which mimicked published analyses, were simulated. Models with 1 to 10 trajectory subgroups were estimated and the model that minimized the Bayes criterion was selected. For each scenario, we assessed whether the method identified the correct number of trajectories, the correct shapes of the trajectories, and the mean number of participants of each trajectory subgroup. The performance of the average posterior probabilities, relative entropy and mismatch criteria to assess classification adequacy were compared.

RESULTS

Among the six scenarios, the correct number of trajectories was identified in two, the correct shapes in four and the mean number of participants of each trajectory subgroup in only one. Relative entropy and mismatch outperformed the average posterior probability in detecting spurious trajectories.

CONCLUSION

Researchers should be aware that GBTM can generate spurious findings, especially when the average posterior probability is used as the sole criterion to evaluate model fit. Several model adequacy criteria should be used to assess classification adequacy.

The influence of disease-modifying therapy on hidden disability burden in people with newly diagnosed relapsing-remitting multiple sclerosis

BACKGROUND

In addition to motor disability, "hidden disability" such as depression, anxiety, fatigue, sleep disturbance, cognitive impairment and pain is a major complaint of people with multiple sclerosis. We explored changes in hidden disability burden in the early post-diagnostic period and examined the hypothesis that disease modifying therapies have a beneficial effect on hidden disability burden.

METHODS

Adults with recently diagnosed (< 6 months) relapsing-remitting multiple sclerosis (n = 440, mean age 37.4 ± 10.4, 76% female), from a national multicentre cohort study (FutureMS) underwent testing with clinical and neuropsychological instruments as well as brain MRI at baseline and after 12-months. Disease modifying therapies were only started after baseline assessment and were classified into injectables (n = 70, interferons, glatiramer acetate), other DMTs (n = 215) and no DMT (n = 117, reference). Sensitivity analyses were undertaken using alternative classifications (disease modifying therapy vs none, and a 3-category system). We performed latent transition analysis with hidden disability burden as the latent variable including propensity score weights.

RESULTS

We identified three classes with low (58%), moderate (25%) and high (17%) hidden disability burden. 70% did not transition ("unchanged", reference), 26% transitioned into a lower burden class ("improvement") and 4% transitioned into a higher burden class ("worsening"). Median treatment duration was 11 months (IQR 9-12). Injectables [OR 1.3 (95%CIs 0.7, 2.3); P = 0.4] and other DMTs [OR 1.4 (95%CIs 0.9, 2.1); P = 0.2] were not associated with significant change in hidden disability burden in either direction ("improvement" or "worsening"). In the alternative 3-category classification, category 2 treatment (fingolimod, cladribine, n = 22) was associated with improvement [OR 4.3 (2.6, 7.0); P < 0.001].

CONCLUSION

Hidden disability was present in most newly diagnosed people with multiple sclerosis. The majority remained unchanged and approximately a quarter improved over the immediate post-diagnostic period. Disease modifying therapy had no significant influence on hidden disability burden in the study period of one year following diagnosis. The trend towards favourable outcomes with fingolimod and cladribine should be interpreted with caution due to the small sample size. Our exploratory data are observational, with scope for attendant biases, but highlight the need for further study including longer-term evaluation as well as randomised trials for non-motor disability.

Evaluation of the times of disability progression and related factors in patients with primary progressive multiple sclerosis from Argentina

Background PPMS (primary progressive multiple sclerosis) patients represent less than 10% of MS patients in Argentina, men and women were similarly affected and most of them had a severe functional impairment. More rapid progression has been reported in males, but this is not the case in all datasets. The main objective of our study was to determine the time to EDSS (Expanded disability Status Scale) 4, 6 and 7 in PPMS patients. We also compared the times to reach these EDSS in men and women and aimed to identify factors associated with the disability progression. Method This cohort of patients with diagnosis of PPMS (n = 253) was selected from follow-up recorded in the RelevarEM registry database. Result The median times to EDSS 4, 6 and 7 were 24 (IQR 12-48), 72 (IQR 36-96) and 96 (IQR 60-120) months, respectively. Comparison of the survival curves to EDSS 4, 6 and 7 according to gender did not show significant differences (p = 0.33, p = 0.55 and p = 0.59). There is no evidence of an association between the clinical adjustment variables (sex, age >40 years at diagnosis, EDSS > 3 at onset and multifocal MS symptoms at disease onset) and the time of arrival at the EDSS 4, 6 and 7. Conclusion Severe disability was observed six years after the onset of symptoms. No association was found between the studied factors and the time to arrival to severe disability.

Longitudinal machine learning modeling of MS patient trajectories improves predictions of disability progression

BACKGROUND AND OBJECTIVES

Research in Multiple Sclerosis (MS) has recently focused on extracting knowledge from real-world clinical data sources. This type of data is more abundant than data produced during clinical trials and potentially more informative about real-world clinical practice. However, this comes at the cost of less curated and controlled data sets. In this work we aim to predict disability progression by optimally extracting information from longitudinal patient data in the real-world setting, with a special focus on the sporadic sampling problem.

METHODS

We use machine learning methods suited for patient trajectories modeling, such as recurrent neural networks and tensor factorization. A subset of 6682 patients from the MSBase registry is used.

RESULTS

We can predict disability progression of patients in a two-year horizon with an ROC-AUC of 0.85, which represents a 32% decrease in the ranking pair error (1-AUC) compared to reference methods using static clinical features.

CONCLUSIONS

Compared to the models available in the literature, this work uses the most complete patient history for MS disease progression prediction and represents a step forward towards AI-assisted precision medicine in MS.

Long-term analysis of patients with benign multiple sclerosis: new insights about the disability course

OBJECTIVE

To describe the course of disability in patients with benign multiple sclerosis-i.e., with an expanded disability status scale score < 3 10 years after disease onset-for up to 30 years after disease onset. We evaluated the proportion of patients remaining in the benign state on the long term and the factor associated with this favorable outcome and determined the pattern of disability course after the loss of the benign status.

METHODS

Patients were selected from the ReLSEP, a French population-based registry. We studied the probability (Kaplan-Meier method) and predictors (multivariate Cox model) of remaining < 3 after year 10, and the course of disability after score 3 according to the duration of the benign phase in patients with ≥ 30 years of follow-up (graphs of the course of the mean expanded disability status scale scores in subgroups of patients).

RESULTS

2295/3440 patients had benign multiple sclerosis (66.7%). The probability of remaining benign at year 30 was 0.26 (95% CI 0.26-0.32). A young age at disease onset and a good recovery after the first relapse were associated with remaining benign. Graphs illustrate that those who lost their benign status between years 10 and 30 follow a two-stage course. Beyond score 3, disability accumulation is similar in all but lower disability scores at advanced age are associated with longer benign periods.

CONCLUSION

The longer a patient remains in the benign state, the lower the final EDSS at advanced age.

Integrating patient-reported outcomes and quantitative timed tasks to identify relapsing remitting multiple sclerosis patient subgroups: a latent profile analysis

BACKGROUND

Multiple sclerosis (MS) patients experience wide-ranging symptoms with varied severity, and approaches that integrate patient-reported outcomes and objective quantitative measures will present opportunities for advancing clinical profiling. The primary objective of the current study was to conduct exploratory data analysis using latent variable modeling to empirically identify clusters of relapsing remitting (RR) MS patients with shared impairment patterns across three patient-reported outcomes and two timed task measures.

METHODS

Latent profile analyses and impairment data for 2,012 RRMS patients identified distinct patient clusters using timed task measures of upper and lower limb performance, and patient-reported outcomes measuring quality of life, depression symptom severity, and perceived global disability. Multinomial logistic regression models were used to characterize associations between socio-demographic attributes and assignment to the patient clusters.

RESULTS

There were 6 distinct clusters of RRMS patients that differed by symptom patterns, and by their socio-demographic attributes. Most notable were were no differences in age, sex, or disease duration between the least and most impaired classes, representing 14% and 4% of patients, respectively. Patients in the most impaired class were much more likely to be Black American, have a history of smoking, have a higher body mass index, and be of lower socioeconomic status than the least impaired class. There were positive relationships between age and classification to clusters of increasing moderately severe impairment but not the most severe clusters.

CONCLUSION

We present a framework for discerning phenotypic impairment clusters in RRMS. The results demonstrate opportunities for advancing clinical profiling, which is necessary for optimizing personalized MS care models and clinical research.

Definitions of primary-progressive multiple sclerosis trajectories by rate of clinical disability progression

BACKGROUND

Patients with primary progressive multiple sclerosis (PPMS) vary in the rate of disability progression.

OBJECTIVE

To classify clinical disability trajectories by rate of disability progression and evaluate predictive variables in PPMS patients.

METHODS

We analyzed the cumulative incidence of progression to disability and in accordance defined clinical PPMS disability trajectories. Correlation was performed with age, gender and disability at first presentation. Estimated onset was calculated and validated by the mathematical slope of disability progression.

RESULTS

The cohort included 304 PPMS patients, 146 (48%) were females, the mean age at first visit was 41.1 years, and the median follow up was 18.9 years. Median time to reach moderate and severe disability was 4.5 years (95%CI 3.8-5.2) and 12.6 years (95%CI 10.1-14.2), respectively. Extremely fast patients (3.3%) progressed to severe disability within 2-years, while very slow patients (4.7%) did not progress to moderate disability even 20 years after first presentation. Age and gender were not associated with progression. Moderate disability at first visit was associated with faster progression to severe disability. Mean estimated range of disease onset was between 4.3 to 9.9 years prior to first presentation.

CONCLUSIONS

Majority of PPMS patients progressed to moderate disability within 5-years and to severe disability within 15-years from first presentation. Clinical disability progression trajectories can help treatment-related decisions.

Longitudinal Trajectories of Hair Cortisol: Hypothalamic-Pituitary-Adrenal Axis Dysfunction in Early Childhood

The objective of this study was to examine if longitudinal trajectories of hair cortisol concentrations (HCC) measured at two or three yearly time points can identify 1-3 year old children at risk for altered hypothalamic-pituitary-adrenal (HPA)-axis function due to early life stress (ELS). HCC was measured (N = 575) in 265 children using a validated enzyme-linked immunosorbent assay. Hair was sampled in Clinic Visits (CV) centered at years 1, 2, and 3 (n = 45); 1 and 2 (n = 98); 1 and 3 (n = 27); 2 and 3 (n = 95). Log-transformed HCC values were partitioned using latent class mixed models (LCMM) to minimize the Bayesian Information Criterion. Multivariable linear mixed effects models for ln-HCC as a function of fixed effects for age in months and random effects for participants (to account for repeated measures) were generated to identify the factors associated with class membership. Children in Class 1 (n = 69; 9% Black) evidenced declining ln-HCC across early childhood, whereas Class 2 members (n = 196; 43% Black) showed mixed trajectories. LCMM with only Class 2 members revealed Class 2A (n = 17, 82% Black) with sustained high ln-HCC and Class 2B (n = 179, 40% Blacks) with mixed ln-HCC profiles. Another LCMM limited to only Class 2B members revealed Class 2B1 (n = 65, 57% Black) with declining ln-HCC values (at higher ranges than Class 1), and Class 2B2 (n = 113, 30% Black) with sustained high ln-HCC values. Class 1 may represent hair cortisol trajectories associated with adaptive HPA-axis profiles, whereas 2A, 2B1, and 2B2 may represent allostatic load with dysregulated profiles of HPA-axis function in response to varying exposures to ELS. Sequential longitudinal hair cortisol measurements revealed the allostatic load associated with ELS and the potential for developing maladaptive or dysregulated HPA-axis function in early childhood.

Long-term worsening of different body functions in persons with progressive multiple sclerosis

Background

It is unclear whether EDSS is responsive to disability worsening in advanced MS.

Objective

To explore the dynamics of disability worsening in persons with advanced-stage MS (EDSS ≥5.5) using three disability worsening definitions (EDSS, Rivermead Mobility Index (RMI), 9-Hole Peg Test (9-HPT)).

Methods

EDSS-, RMI- and 9-HPT-based disability worsening were assessed over a minimum of two years in a cohort of 286 persons with advanced MS attending inpatient rehabilitation using Kaplan-Meier Curves and multivariable Cox regression. Furthermore, the correspondence between EDSS-, RMI- and 9-HPT-based disability worsening was analyzed.

Results

Disability progression was observed in 49% (9-HPT), 52% (EDSS) and 53% (RMI), with 9-HPT-based worsening slightly lagging behind. The Multiple Sclerosis Severity Score (MSSS) was the only consistent factor predicting disability worsening based on all three definitions (EDSS: hazard ratio 1.48 [1.30;1.68]; RMI: 1.12 [0.99;1.27]; 9-HPT: 1.36 [1.18;1.57]). Correspondence between EDSS and the other definitions (9-HPT and RMI) was 44.3% and 55.7% at time of EDSS progression and 65.1% and 72.5% overall, respectively.

Conclusion

In persons with advanced-stage MS, half still developed disability worsening in different functional systems over a median of 6 years. MSSS seems a valid predictor for disability worsening in all three outcome measures in advanced MS.

Latent Class Trajectory Modeling of 2-Component Disease Activity Score in 28 Joints Identifies Multiple Rheumatoid Arthritis Phenotypes of Response to Biologic Disease-Modifying Antirheumatic Drugs

OBJECTIVE

To determine whether using a reweighted disease activity score that better reflects joint synovitis, i.e., the 2-component Disease Activity Score in 28 joints (DAS28) (based on swollen joint count and C-reactive protein level), produces more clinically relevant treatment outcome trajectories compared to the standard 4-component DAS28.

METHODS

Latent class mixed modeling of response to biologic treatment was applied to 2,991 rheumatoid arthritis (RA) patients in whom treatment with a biologic disease-modifying antirheumatic drug was being initiated within the Biologics in Rheumatoid Arthritis Genetics and Genomics Study Syndicate cohort, using both 4-component and 2-component DAS28 scores as outcome measures. Patient groups with similar trajectories were compared in terms of pretreatment baseline characteristics (including disability and comorbidities) and follow-up characteristics (including antidrug antibody events, adherence to treatments, and blood drug levels). We compared the trajectories obtained using the 4- and 2-component scores to determine which characteristics were better captured by each.

RESULTS

Using the 4-component DAS28, we identified 3 trajectory groups, which is consistent with previous findings. We showed that the 4-component DAS28 captures information relating to depression. Using the 2-component DAS28, 7 trajectory groups were identified; among them, distinct groups of nonresponders had a higher incidence of respiratory comorbidities and a higher proportion of antidrug antibody events. We also identified a group of patients for whom the 2-component DAS28 scores remained relatively low; this group included a high percentage of patients who were nonadherent to treatment. This highlights the utility of both the 4- and 2-component DAS28 for monitoring different components of disease activity.

CONCLUSION

Here we show that the 2-component modified DAS28 defines important biologic and clinical phenotypes associated with treatment outcome in RA and characterizes important underlying response mechanisms to biologic drugs.

The apparently milder course of multiple sclerosis: changes in the diagnostic criteria, therapy and natural history

In the past decade, changes have occurred in the spectrum of multiple sclerosis courses. The natural history of multiple sclerosis appears milder from the first sign of demyelinating disease to the progressive course, probably as a result of an interplay between several factors including changes in the diagnostic criteria, changes in the epidemiology of multiple sclerosis, impact of early and appropriate disease-modifying treatment and improvement of the general state of health in the population. It has been suggested to regard incidental findings of demyelinating lesions in MRI in individuals without any history of clinical symptoms consistent with neurological dysfunction, so-called radiological isolated syndrome, as the initial course of multiple sclerosis. New diagnostic criteria have enabled the multiple sclerosis diagnosis in many patients at the first clinical demyelinating event, clinically isolated syndrome. The remaining patients with clinically isolated syndrome have a more benign prognosis, and for relapsing-remitting multiple sclerosis, the prognosis has become more favourable. Reduced disease activity in patients with relapsing-remitting multiple sclerosis can partly be ascribed to more efficacious new disease-modifying therapies but decrease in disease activity has also be seen in placebo-treated patients in clinical trials. This may be explained by several factors: change in the diagnostic criteria, more explicit inclusion criteria, exclusion of high-risk patients e.g. patients with co-morbidities, and more rigorous definitions of relapses and disease worsening. However, these factors also make the disease course in patients treated with disease-modifying therapies seem more favourable. In addition, change in the therapeutic target to stable disease (no evidence of disease activity = no relapses, no disease worsening and no MRI activity) could by itself change the course in relapsing-remitting multiple sclerosis. The effectiveness of disease-modifying drugs has reduced the transition from relapsing-remitting to secondary progressive multiple sclerosis. The concept of progressive multiple sclerosis has also evolved from two very distinct categories (primary progressive and secondary progressive multiple sclerosis) to a unified category of progressive multiple sclerosis, which can then be split into the categories of active or inactive. Also, an increasing tendency to treat progressive multiple sclerosis with disease-modifying therapies may have contributed to change the course in progressive multiple sclerosis. In conclusion, during the past decade the entire course of multiple sclerosis from the first sign of a demyelinating disorder through the progressive course appears to be milder due to a complex interplay of several factors.

Harmonization of real-world studies in multiple sclerosis: Retrospective analysis from the rirems group

BACKGROUND

Worldwide multiple sclerosis (MS) centers have coordinated their efforts to use data acquired in clinical practice for real-world observational studies. In this retrospective study, we aim to harmonize outcome measures, and to evaluate their heterogeneity within the Rising Italian Researchers in MS (RIReMS) study group.

METHODS

RIReMS members filled in a structured questionnaire evaluating the use of different outcome measures in clinical practice. Thereafter, thirty-four already-published papers from RIReMS centers were used for heterogeneity analyses, using the DerSimonian and Laird random-effects method to compute the between-study variance (τ²).

RESULTS

Based on questionnaire results, we defined basic modules for diagnosis and follow-up, consisting of outcome measures recorded by all participating centers at the time of diagnosis, and, then, at least annually; we also defined more detailed/optional modules, with outcome measures recorded less frequently and/or in the presence of specific clinical indications. Looking at heterogeneity, we found 5-year variance in age at onset (ES=27.34; 95%CI=26.18, 28.49; p<0.01; τ²=4.76), and 7% in female percent (ES=66.42; 95%CI=63.08, 69.76; p<0.01; τ²=7.15). EDSS variance was 0.2 in studies including patients with average age <36.1 years (ES=1.96; 95%CI=1.69, 2.24; p<0.01; τ²=0.19), or from 36.8 to 41.1 years (ES=2.70; 95%CI=2.39, 3.01; p<0.01; τ²=0.18), but increased to 3 in studies including patients aged >41.4 years (ES=4.37; 95%CI=3.40, 5.35; p<0.01; τ²=2.96). The lowest variance of relapse rate was found in studies with follow-up duration ≤2 years (ES=9.07; 95%CI=5.21, 12.93; p = 0.02; τ²=5.53), whilst the lowest variance in EDSS progression was found in studies with follow-up duration >2 years (ES=5.41; 95%CI=3.22, 7.60; p = 0.02; τ²=1.00).

DISCUSSION

We suggest common sets of biomarkers to be acquired in clinical practice, that can be used for research purposes. Also, we provide researchers with specific indications for improving inclusion criteria and data analysis, ultimately allowing data harmonization and high-quality collaborative studies.

Real-World Effectiveness and Safety of Fingolimod in Patients With Relapsing Remitting Multiple Sclerosis: A Prospective Analysis in Buenos Aires, Argentina

OBJECTIVES

The aim of this prospective observational postmarketing study was to evaluate fingolimod effectiveness in a real-world setting in Buenos Aires, Argentina.

METHODS

Relapsing remitting multiple sclerosis patients who had been prescribed fingolimod owing to treatment failure and had at least greater than or equal to 24 months of follow-up were included during August 2013 and June 2018. Three-monthly clinical evaluations and 12-monthly magnetic resonance were performed. Demographic and clinical variables were described as well as the safety and the effectiveness outcomes that included the proportion of patients free from clinical relapses, from disability progression, from new or enlarging T2 or T1 gadolinium-enhancing lesions on annual magnetic resonance imaging, and from any disease activity during the follow-up.

RESULTS

A total of 97 patients were included (68% female [n = 66]; mean ± SD age, 30 ± 10.5 years; mean ± SD disease duration, 6.5 ± 3.1 years; mean ± SD Expanded Disability Status Scale, 3.5 ± 1; mean ± SD fingolimod use, 30 ± 13 months [range, 18-56 months]). One hundred percent (97) used previous disease-modifying therapy, mainly interferons (87%; n = 84). Fourteen patients (14.4%) discontinued/withdrew fingolimod (10 owing to disease activity and 4 owing to tolerance and personal decisions). Eighty-two percent were free from clinical relapses, and 85% were free from disability progression; 75% of patients remained free from new or newly enlarging T2 lesions, and 78% of patients were free from gadolinium enhancing lesions. The proportion of patients free from any disease activity was 54%.

CONCLUSIONS

The effectiveness of fingolimod in a newly real-world setting was consistent with information provided from phase III clinical trials.

Association of Inflammation and Disability Accrual in Patients With Progressive-Onset Multiple Sclerosis

Importance

The role of inflammatory disease activity as a determinant of disability in progressive-onset multiple sclerosis (MS) remains contested.

Objective

To examine the association of superimposed relapses in progressive-onset MS on disease outcomes.

Design, Setting, and Participants

Observational cohort study from MSBase, a prospectively collected, international database. Data were collected between January 1995 and February 2017. Analyses began in February 2017. From 44 449 patients at time of extraction, 1419 eligible patients (31.9%) were identified for analysis. Inclusion criteria consisted of primary progressive MS (PPMS) or progressive-relapsing MS (PRMS), adult-onset disease, and minimum data set (including ≥3 visits with disability recorded, ≥3 months between second and last visit). Data were analyzed using multivariable regression models (Andersen-Gill) with mixed effects. Two sensitivity analyses to exclude both relapse-related disability progression and bout-onset progressive MS were performed.

Exposures

Grouped according to presence or absence of relapse, defined as an acute episode of clinical worsening. Quantifiable disability change or correlation on imaging was not required to confirm relapse.

Main Outcomes and Measures

Cumulative hazard of disability progression.

Results

Patients with PRMS were younger than those with PPMS (mean [SD] age, 46 [15] vs 51 [10] years, Cohen d = 0.40) and demonstrated a mean lower Expanded Disability Status Scale score (mean [SD] score, 4.0 [3] vs 4.5 [2.5], Cohen d = 0.28) at inclusion. The ratio of men to women was similar in the PRMS and PPMS groups (252:301 vs 394:472). The overall mean (SD) age was 48 (11) years for men and 50 (10) years for women. Likelihood of confirmed disability progression was lower in patients with superimposed relapses (hazard ratio [HR], 0.83; 95% CI, 0.74-0.94; P = .003). Proportion of follow-up time spent on disease-modifying therapy significantly reduced the hazard of confirmed disability progression in the cohort with relapse (HR, 0.96; 95% CI, 0.94-0.99; P = .01) but not in those without relapse (HR, 1.02; 95% CI, 0.99-1.05; P = .26). When accounting for relapse-related progression, the association of disease-modifying therapy in the cohort with superimposed relapse was no longer observed (HR, 1.10; 95% CI, 0.96-1.24; P = .16).

Conclusions and Relevance

In progressive-onset MS, superimposed relapses are associated with a lower risk of confirmed disability progression. This is most likely attributed to the association of disease-modifying therapy with the prevention of relapse-related disability accrual in patients with superimposed relapse. These findings suggest that inflammatory relapses are an important and modifiable determinant of disability accrual in progressive-onset disease.

Functional and self-care capacity of people with multiple sclerosis

Objective:

describe the self-care and functionality levels of patients with multiple sclerosis and determine whether sociodemographic, clinical and functional variables interfere with self-care and/or functionality.

Method:

correlational, cross-sectional study with a quantitative approach performed with individuals in outpatient follow-up. We collected sociodemographic and clinical data and applied the Appraisal of Self-care Agency Scale, the Barthel index, the Lawtton and Brody Scale, and the instrument to investigate the performance in Advanced Activities of Daily Living. We performed descriptive and inferential analysis.

Results:

most patients were classified as “having self-care” (82.14%); with moderate dependence (51.19%) for the basic activities of daily living, partial dependence for the instrumental activities of daily living (55.95%), and more active for the advanced activities of daily living (85.71%). Patients with longer disease duration had a higher number of disabilities and, in those with better socioeconomic and educational profile, the functionality was better.

Conclusion:

disease duration was strongly correlated with a higher number of disabilities and better socioeconomic and educational profiles showed to be protective factors for functionality. Care planning should consider the needs observed by the multidisciplinary team, stimulating the development of self-care, functionality and sociability.

The MSBase registry: Informing clinical practice

Over the last decade, clinical registries have significantly contributed to the pool of evidence that supports management decisions in patients with multiple sclerosis. Being the largest international registry of multiple sclerosis and neuroimmunological disorders, MSBase collects demographic, clinical and limited paraclinical information from patients managed in different regions and under various circumstances. In this review, we will provide an overview of its published output, with focus on the information with impact on the management of multiple sclerosis.

'Progressive MS - macro views': The need for novel clinical trial paradigms to enable drug development for progressive MS

This article outlines the principal challenges to establish a standard phase-2 approach for progressive multiple sclerosis (PMS) and presents referring strategies to accelerate the registration process via a guidance approved by regulatory agencies. Accordingly, the contribution of 'big datasets' for a better understanding of the natural history of primary-progressive multiple sclerosis (PPMS) and secondary-progressive multiple sclerosis (SPMS) and of their prognostic factors and the value of novel biomarkers are discussed. The establishment of new industry-academic initiatives, such as independent consortia under the umbrella of Progressive MS Alliance (PMSA), with the endorsement of MS organizations and Scientific Societies (e.g. European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS)) may be crucial to overcome some of the current challenges. Within this frame, the continuous interaction with regulatory agencies is instrumental for the formal validation of the many developments suitable to improve clinical trialling in PMS.

Clinical outcome measures for progressive MS trials

Treatment options for progressive multiple sclerosis remain the main unmet need of the field. As the understanding of multiple sclerosis (MS) pathogenesis improves, new pathways and molecules will be tested for potential reparative, remyelinating, or neuroprotective effects. The clinical outcomes used will determine successful demonstration of beneficial treatment effects to regulatory agencies, clinicians, and persons with MS. This review focuses on clinical outcome measures including the Expanded Disability Status Scale, Multiple Sclerosis Functional Composite, and novel composite measures of disability. The paper also covers cognitive outcomes and screening tests for use in clinical trials. The growing importance of patient-reported outcomes and their suitability for clinical trials is also presented. The review aims to create consensus in regard to these topics and suggestions for future research.

Metabolomic Profiles for Primary Progressive Multiple Sclerosis Stratification and Disease Course Monitoring

Primary progressive multiple sclerosis (PPMS) shows a highly variable disease progression with poor prognosis and a characteristic accumulation of disabilities in patients. These hallmarks of PPMS make it difficult to diagnose and currently impossible to efficiently treat. This study aimed to identify plasma metabolite profiles that allow diagnosis of PPMS and its differentiation from the relapsing-remitting subtype (RRMS), primary neurodegenerative disease (Parkinson’s disease, PD), and healthy controls (HCs) and that significantly change during the disease course and could serve as surrogate markers of multiple sclerosis (MS)-associated neurodegeneration over time. We applied untargeted high-resolution metabolomics to plasma samples to identify PPMS-specific signatures, validated our findings in independent sex- and age-matched PPMS and HC cohorts and built discriminatory models by partial least square discriminant analysis (PLS-DA). This signature was compared to sex- and age-matched RRMS patients, to patients with PD and HC. Finally, we investigated these metabolites in a longitudinal cohort of PPMS patients over a 24-month period. PLS-DA yielded predictive models for classification along with a set of 20 PPMS-specific informative metabolite markers. These metabolites suggest disease-specific alterations in glycerophospholipid and linoleic acid pathways. Notably, the glycerophospholipid LysoPC(20:0) significantly decreased during the observation period. These findings show potential for diagnosis and disease course monitoring, and might serve as biomarkers to assess treatment efficacy in future clinical trials for neuroprotective MS therapies.

Genotype and Phenotype in Multiple Sclerosis-Potential for Disease Course Prediction?

PURPOSE OF REVIEW

This review will examine the current evidence that genetic and/or epigenetic variation may influence the multiple sclerosis (MS) clinical course, phenotype, and measures of MS severity including disability progression and relapse rate.

RECENT FINDINGS

There is little evidence that MS clinical phenotype is under significant genetic control. There is increasing evidence that there may be genetic determinants of the rate of disability progression. However, studies that can analyse disability progression and take into account all the confounding variables such as treatment, clinical characteristics, and environmental factors are by necessity longitudinal, relatively small, and generally of short duration, and thus do not lend themselves to the assessment of hundreds of thousands of genetic variables obtained from GWAS. Despite this, there is recent evidence to support the association of genetic loci with relapse rate. Recent progress suggests that genetic variations could be associated with disease severity, but not MS clinical phenotype, but these findings are not definitive and await replication. Pooling of study results, application of other genomic techniques including epigenomics, and analysis of biomarkers of progression could functionally validate putative severity markers.