Risk of Multiple Sclerosis in People Living with HIV: An International Cohort Study.

OBJECTIVE: There has been interest in a possible negative association between HIV and multiple sclerosis (MS). We aimed to compare the risk of MS in a cohort of individuals living with HIV to that in the general population. METHODS: Population-based health data were accessed for 2 cohorts of HIV-positive persons from Sweden and British Columbia, Canada. Incident MS was identified using MS registries or a validated algorithm applied to administrative data. Individuals with HIV were followed from 1 year after the first clinical evidence of HIV or the first date of complete administrative health data (Canada = April 1, 1992 and Sweden = January 1, 2001) until the earliest of incident MS, emigration, death, or study end (Canada = March 31, 2020 and Sweden = December 31, 2018). The observed MS incidence rate in the HIV-positive cohort was compared to the expected age-, sex-, calendar year-, income-specific, and region of birth-specific rates in a randomly selected sample of >20% of each general population. The standardized incidence ratio (SIR) for MS following the first antiretroviral therapy exposure ("ART-exposed") was also calculated. RESULTS: The combined Sweden-Canada cohort included 29,163 (75% men) HIV-positive persons. During 242,248 person-years of follow-up, 14 incident MS cases were observed in the HIV-positive cohort, whereas 26.19 cases were expected. The SIR for MS in the HIV-positive population was 0.53 (95% confidence interval [CI] = 0.32-0.90). The SIR for MS following the first ART exposure was 0.55 (95% CI = 0.31-0.96). INTERPRETATION: This international population-based study demonstrated a lower risk of MS among HIV-positive individuals, and HIV-positive ART-exposed individuals. These findings provide support for further exploration into the relationship among HIV, ART, and MS. ANN NEUROL 2024;95:487-494.

Association of multiple-sclerosis-related mortality with COVID-19 and other common infections: a multiple causes of death analysis.

BACKGROUND AND PURPOSE: People with multiple sclerosis (MS) suffer from higher infection-related mortality compared to the general population; however, sparse data are available on the increased risk of death associated with coronavirus disease 2019 (COVID-19) and other common types of infections. METHODS: All mortality records and multiple-cause-of-death data in 2010-2021 of residents in the Veneto region (northeastern Italy) were extracted. Mention of specific infections was compared between death certificates reporting MS or not. Odds ratios (OR) with 95% confidence intervals (95% CI) were estimated by conditional logistic regression matching by age, sex and calendar year. The bimonthly averages of MS-related deaths in 2010-2019 were compared with those registered during the pandemic (2020-2021). RESULTS: Of 580,015 deaths through 2010-2021, MS was mentioned in 850 cases (0.15%), 59.3% women. Influenza and pneumonia were reported in 18.4% of MS-related compared to 11.0% non-MS-related deaths (OR 2.72, 95% CI 2.28-3.25). The odds of mention of urinary tract infections was significantly greater in MS-related deaths of men (OR 8.16, 95% CI 5.23-12.7) than women (OR 3.03, 95% CI 1.82-5.02). Aspiration pneumonia, pressure ulcers/skin infections and sepsis were also significantly associated with MS-related deaths. Reporting of COVID-19 as a cause of death did not significantly differ between deaths with and without mention of MS (approximately 11% of both). However, compared to 2010-2019, peaks in MS-related deaths were observed during the pandemic waves. CONCLUSIONS: Infections continue to play a significant role in MS-related deaths, underlying the need to improve prevention and management strategies.

Care consumption of people with multiple sclerosis: A multichannel sequence analysis in a population-based setting in British Columbia, Canada.

BACKGROUND: Persons with multiple sclerosis (PwMS) typically require complex multidisciplinary care, which is rarely formally assessed. OBJECTIVES: We applied multichannel sequence analysis (MCSA) to identify care consumption patterns by PwMS in British Columbia, Canada. METHODS: We created two cohorts, comprising incident and prevalent MS cases, using linked clinical and administrative data. We applied MCSA to quantify and compare the care pathways of PwMS, based on all-cause hospitalizations and physician visits (divided into five specialities). Care consumption clusters were characterized using demographic and clinical features. RESULTS: From 1048 incident and 3180 prevalent PwMS, the MCSA identified 12 and 6 distinct care consumption clusters over a median follow-up of 9.6 and 13.0 years, respectively. Large disparities between clusters were observed; the median number of annual consultations ranged from 5.6 to 21.3 for general practitioners, 1.2 to 4.6 for neurologists and 0 to 5.3 for psychiatrists in the incident cohort. Characteristics at MS symptom onset associated with the highest care consumption included high comorbidity burden and older age. There were similar disparities and associations for prevalent PwMS. CONCLUSION: The distinct patterns of care consumption, which were reminiscent of the heterogeneity of MS itself, may facilitate health service planning and evaluation, and provide a novel outcome measure in health research.

Disease-modifying drugs for multiple sclerosis and subsequent health service use.

OBJECTIVE: We assessed the relationship between the multiple sclerosis (MS) disease-modifying drugs (DMDs) and healthcare use. METHODS: Persons with MS (aged ⩾18 years) were identified using linked population-based health administrative data in four Canadian provinces and were followed from the most recent of their first MS/demyelinating event or 1 January 1996 until the earliest of death, emigration, or study end (31 December 2017 or 31 March 2018). Prescription records captured DMD exposure, examined as any DMD, then by generation (first-generation (the injectables) or second-generation (orals/infusions)) and individual DMD. The associations with subsequent all-cause hospitalizations and physician visits were examined using proportional means model and negative binomial regression. RESULTS: Of 35,894 MS cases (72% female), mean follow-up was 12.0 years, with person-years of DMD exposure for any, or any first- or second-generation DMD being 63,290, 54,605 and 8685, respectively. Any DMD or any first-generation DMD exposure (versus non-exposure) was associated with a 24% lower hazard of hospitalization (adjusted hazard ratio, aHR: 0.76; 95% confidence intervals (CIs): 0.71-0.82), rising to 29% for the second-generation DMDs (aHR: 0.71; 95% CI: 0.58-0.88). This ranged from 18% for teriflunomide (aHR: 0.82; 95% CI: 0.67-1.00) to 44% for fingolimod (aHR: 0.56; 95% CI: 0.36-0.87). In contrast, DMD exposure was generally not associated with substantial differences in physician visits. CONCLUSION: Findings provide real-world evidence of a beneficial relationship between DMD exposure and hospitalizations.

Dealing With Treatment-Confounder Feedback and Sparse Follow-up in Longitudinal Studies: Application of a Marginal Structural Model in a Multiple Sclerosis Cohort.

The beta-interferons are widely prescribed platform therapies for patients with multiple sclerosis (MS). We accessed a cohort of patients with relapsing-onset MS from British Columbia, Canada (1995-2013), to examine the potential survival advantage associated with beta-interferon exposure using a marginal structural model. Accounting for potential treatment-confounder feedback between comorbidity, MS disease progression, and beta-interferon exposure, we found an association between beta-interferon exposure of at least 6 contiguous months and improved survival (hazard ratio (HR) = 0.63, 95% confidence interval 0.47, 0.86). We also assessed potential effect modifications by sex, baseline age, or baseline disease duration, and found these factors to be important effect modifiers. Sparse follow-up due to variability in patient contact with the health system is one of the biggest challenges in longitudinal analyses. We considered several single-level and multilevel multiple imputation approaches to deal with sparse follow-up and disease progression information; both types of approach produced similar estimates. Compared to ad hoc imputation approaches, such as linear interpolation (HR = 0.63), and last observation carried forward (HR = 0.65), all multiple imputation approaches produced a smaller hazard ratio (HR = 0.53), although the direction of effect and conclusions drawn concerning the survival advantage remained the same.

A multiple sclerosis disease progression measure based on cumulative disability.

BACKGROUND: Existing severity measurements in multiple sclerosis (MS) are often cross-sectional, making longitudinal comparisons of disease course between individuals difficult. OBJECTIVE: The objective of this study is to create a severity metric that can reliably summarize a patient's disease course. METHODS: We developed the nARMSS - normalized ARMSS (age-related MS severity score) over follow-up, using the deviation of individual ARMSS scores from the expected value and integrated over the corresponding time period. The nARMSS scales from -5 to +5; a positive value indicates a more severe disease course for a patient when compared to other patients with similar disease timings. RESULTS: Using Swedish MS registry data, the nARMSS was tested using data at 2 and 4 years of follow-up to predict the most severe quartile during the subsequent period up to 10 years total follow-up. The metric used was area under the curve of the receiver operating characteristic (AUC-ROC). This resulted in measurements of 0.929 and 0.941. In an external Canadian validation cohort, the equivalent AUC-ROCs were 0.901 and 0.908. CONCLUSION: The nARMSS provides a reliable, generalizable and easily measurable metric which makes longitudinal comparison of disease course between individuals feasible.

Adherence to laboratory monitoring among people taking oral drugs for multiple sclerosis: A Canadian population-based study.

OBJECTIVE: To examine laboratory testing adherence by persons initiating an oral disease-modifying therapy (DMT) for multiple sclerosis (MS). METHODS: Population-based health administrative and laboratory data were accessed in British Columbia, Canada, to identify everyone filling their first prescription for dimethyl fumarate (DMF), fingolimod or teriflunomide (2011-2015). The proportion of people adherent to each drug monograph's recommended laboratory monitoring schedule, pre- and on-DMT, was estimated. The association between patient characteristics and adherence was examined using multivariable logistic regression. RESULTS: A total of 1016 people were included (DMF 567, fingolimod 253 and teriflunomide 196). The proportions of people adherent to pre-DMT liver and lymphocyte tests ranged from 88% to 91% and 91% to 94%, respectively, while 77% adhered to pre-DMF urinalysis. Adherence to the first on-DMT liver test was 89% for DMF (within 6 months), 61% for fingolimod (within 3 months) and 40% for teriflunomide (within 1 month). Men were less likely than women to have pre-DMF urinalysis (adjusted odds ratio (aOR); 95% confidence interval (CI): 0.40-0.95) or on-DMF liver (aOR: 0.46; 95% CI: 0.23-0.95) or lymphocyte (aOR: 0.47; 95% CI: 0.22-0.98) tests. CONCLUSIONS: Adherence to recommended laboratory testing was high (>77%) before oral DMT initiation, but lower once on drug. There is a need to understand the long-term consequences of suboptimal laboratory monitoring and sex differences in the DMT-treated MS population.

Accurate classification of secondary progression in multiple sclerosis using a decision tree.

BACKGROUND: The absence of reliable imaging or biological markers of phenotype transition in multiple sclerosis (MS) makes assignment of current phenotype status difficult. OBJECTIVE: The authors sought to determine whether clinical information can be used to accurately assign current disease phenotypes. METHODS: Data from the clinical visits of 14,387 MS patients in Sweden were collected. Classifying algorithms based on several demographic and clinical factors were examined. Results obtained from the best classifier when predicting neurologist recorded disease classification were replicated in an independent cohort from British Columbia and were compared to a previously published algorithm and clinical judgment of three neurologists. RESULTS: A decision tree (the classifier) containing only most recently available expanded disability scale status score and age obtained 89.3% (95% confidence intervals (CIs): 88.8-89.8) classification accuracy, defined as concordance with the latest reported status. Validation in the independent cohort resulted in 82.0% (95% CI: 81.0-83.1) accuracy. A previously published classification algorithm with slight modifications achieved 77.8% (95% CI: 77.1-78.4) accuracy. With complete patient history of 100 patients, three neurologists obtained 84.3% accuracy compared with 85% for the classifier using the same data. CONCLUSION: The classifier can be used to standardize definitions of disease phenotype across different cohorts. Clinically, this model could assist neurologists by providing additional information.

Fatigue, sleep disorders, anaemia and pain in the multiple sclerosis prodrome.

BACKGROUND: There is increasing evidence of prodromal multiple sclerosis (MS). OBJECTIVE: The aim of this study was to determine whether fatigue, sleep disorders, anaemia or pain form part of the MS prodrome. METHODS: This population-based matched cohort study used linked administrative and clinical databases in British Columbia, Canada. The odds of fatigue, sleep disorders, anaemia and pain in the 5 years preceding the MS cases' first demyelinating claim or MS symptom onset were compared with general population controls. The frequencies of physician visits for these conditions were also compared. Modifying effects of age and sex were evaluated. RESULTS: MS cases/controls were assessed before the first demyelinating event (6863/31,865) or MS symptom onset (966/4534). Fatigue (adj.OR: 3.37; 95% CI: 2.76-4.10), sleep disorders (adj.OR: 2.61; 95% CI: 2.34-2.91), anaemia (adj.OR: 1.53; 95% CI: 1.32-1.78) and pain (adj.OR: 2.15; 95% CI: 2.03-2.27) during the 5 years preceding the first demyelinating event were more frequent among cases, and physician visits increased for cases relative to controls. The association between MS and anaemia was greater for men; that between MS and pain increased with age. Pre-MS symptom onset, sleep disorders (adj.OR: 1.72; 95% CI: 1.12-2.56) and pain (adj.OR: 1.53; 95% CI: 1.32-1.76) were more prevalent among cases. CONCLUSION: Fatigue, sleep disorders, anaemia and pain were elevated before the recognition of MS. The relative anaemia burden was higher in men and pain more evident among older adults.

Age-related decreases in relapses among adults with relapsing-onset multiple sclerosis.

BACKGROUND: Relapsing-onset multiple sclerosis (MS) typically starts in early- to mid-adulthood, yet the trajectory of disease activity over the subsequent lifetime remains poorly defined. Previous studies have not quantified the age-specific portion of decreases in annualized relapse rates (ARR). OBJECTIVE: The aim of this article is to determine, under a range of disease-related assumptions, the age-specific component of decreases in ARR over time among adults with relapsing-onset MS. METHODS: We used a simulation modeling approach to examine a range of assumptions about changes in ARR due to age versus disability status. Scenarios included variations in initial ARR and rate of worsening on the Expanded Disability Status Scale. Model parameters were developed through analysis of MS patients in British Columbia, Canada, and literature review. RESULTS: We found a substantial age-specific decrease in ARR in all simulated scenarios, independent of disability worsening. Under a range of clinically plausible assumptions, 88%-97% of the decrease was attributed to age and 3%-13% to disability. The age-specific decrease ranged from 22% to 37% per 5 years for a wide range of initial ARR (0.33-1.0). CONCLUSION: Decreases in ARR were due mostly to age rather than disability status. To facilitate informed decision making in MS, it is important to quantify the dynamic relationship between relapses and age.

Disparities in management and outcomes of myocardial infarction in multiple sclerosis: A matched cohort study.

BACKGROUND: Although multiple sclerosis (MS) confers an elevated risk of acute myocardial infarction (AMI), little is known about how it influences management of AMI. METHODS: Using population-based administrative (health) data from two Canadian provinces, we conducted a retrospective matched cohort study. We identified people with MS who had an incident AMI, and up to five AMI controls without MS matched on age, sex, and region. We compared the likelihood of undergoing cardiac catheterization within 30 days of AMI, time to revascularization, use of recommended pharmacotherapy post-AMI, and mortality at 30 and 365 days post-AMI using multivariable regression models adjusting for potential confounders. We pooled findings across provinces using meta-analysis. RESULTS: We identified 559 MS cases and 2523 matched controls. In the matched cohort, the MS cohort was less likely to undergo cardiac catheterization within 30 days of admission (odds ratio (OR) = 0.61; 95% confidence interval (CI) = 0.49-0.77), revascularization (hazard ratio (HR) = 0.78; 95% CI = 0.69-0.88), or to fill a prescription for recommended therapy. Mortality risk was higher in the MS cohort than in the matched cohort at 30 and 365 days post-AMI. CONCLUSION: Rates of diagnostic and therapeutic care, and survival after AMI were lower in the MS population than in a matched population.

Causes that Contribute to the Excess Mortality Risk in Multiple Sclerosis: A Population-Based Study.

BACKGROUND: Lifespan is 6-10 years shorter in multiple sclerosis (MS), but the reasons remain unclear. Using linked clinical- and population-based administrative health databases, we compared cause-specific mortality in an MS cohort to the general population. METHODS: MS patients in British Columbia (BC), Canada, were followed from the later of first MS clinic visit or January 1, 1986, to the earlier of death, emigration, or December 31, 2013. Comprehensive mortality information was obtained by linkage to BC's multiple-cause-of-death mortality data. Causes were grouped using International Classification of Disease codes. Standardized mortality ratios (SMRs) were calculated for underlying cause, and relative mortality ratios (RMRs) for any mention cause, by comparison to mortality rates in the age-, sex-, and calendar year-matched general population. Cause-specific relative mortality was explored by sex and disease course (relapsing onset and primary progressive). RESULTS: Among 6,629 MS patients with 104,236 patient-years of follow-up, 1,416 died. The all-cause mortality risk was increased relative to the general population (SMR 2.71; 95% CI 2.55-2.87). MS was the underlying cause in 50.4%, and a mentioned cause in 77.9%, of deaths. Mortality by underlying cause was higher than expected for genitourinary disorders/infections (SMR 3.55; 95% CI 2.25-5.32), respiratory diseases/infections (SMR 2.69; 95% CI 2.17-3.28), suicide (SMR 2.40; 95% CI 1.61-3.45), cardiovascular disease (SMR 1.57; 95% CI 1.36-1.81), and other infections/septicemia (SMR 1.83; 95% CI 1.15-2.78). Risks of death due to overall cancer, accidents, digestive system disorders, and endocrine/nutritional diseases as underlying causes were similar to the general population. However, mortality with any mention of accidents (RMR 2.71; 95% CI 2.22-3.29) or endocrine/nutritional diseases (RMR 1.75; 95% CI 1.46-2.09) was greater. Bladder cancer mortality was increased in women (SMR 3.87; 95% CI 1.42-8.42) but not men. No notable differences were observed by disease course. CONCLUSIONS: MS itself was the most frequent underlying cause of death. Infections (genitourinary, respiratory, and septicemia), suicides, cardiovascular disease, and accidents contributed significantly to the increased risk of death. Some findings differed by sex, but not disease course. Multiple-cause death data offer advantages over "traditional" use of underlying cause only.

Interrogation of the Multiple Sclerosis Prodrome Using High-Dimensional Health Data.

BACKGROUND: There is growing evidence of a prodromal period in multiple sclerosis (MS). A better understanding of the prodrome may facilitate prompt recognition and treatment of MS as well as narrowing of the etiologically relevant -period when searching for MS risk factors. OBJECTIVES: To explore and further delineate the MS prodrome, we used statistical learning techniques to examine associations of physician-generated diagnostic codes and prescription medication classes in the 5 years before the first demyelinating-related claim for MS cases and matched population controls. METHODS: In this matched cohort study, we accessed data from linked health administrative hospital, physician, and prescription databases from British Columbia, Canada, between 1996 and 2013. We focused on 7 medication classes previously identified as associated with the MS prodrome: urinary anti-spasmodics, glucocorticoids, muscle relaxants, anti-epileptics, dopa-derivatives, benzodiazepine, and antivertigo preparations. Diagnostic codes associated with the use of each medication class were first identified using LASSO logistic regression analyses in two-thirds of the cohort and then validated using multivariate logistic regressions in the remaining cohort. RESULTS: Our analyses included 4,862 MS cases and 22,649 controls. Although the identified diagnostic codes showed fair to good predictive performance in 6 medication classes (C-index = 0.712-0.858), these codes failed to fully explain the higher usage of these medications by the MS cases. Compared to controls of the same age, sex, and diagnostic codes, MS cases had higher odds of filling a prescription for antivertigo preparations (adjusted OR [aOR] 2.48; 95% CI 1.92-3.19), anti-epileptics (aOR 2.34; 1.90-2.90), glucocorticoids (aOR 1.76; 1.52-2.03), urinary anti-spasmodics (aOR 1.72; 1.20-2.46), and muscle relaxants (aOR 1.33; 1.13-1.56). CONCLUSIONS: We observed markedly higher use of specific medications in MS cases in the 5 years before the first demyelinating claim. The overrepresentation of specific medications in MS cases, which was not fully explained by the physician diagnoses, may represent a signature of the MS prodrome.

Multiple sclerosis: effect of beta interferon treatment on survival.

Worldwide, the beta interferons remain the most commonly prescribed disease-modifying drugs for multiple sclerosis. However, it is unclear if they alter survival. We investigated the association between beta interferon and mortality in the 'real-world' setting. This was a multi-centre population-based observational study of patients with relapsing-onset multiple sclerosis who were initially registered at a clinic in British Columbia, Canada (1980-2004) or Rennes, France (1976-2013). Data on this cohort were accessed from the clinical multiple sclerosis databases and from individually linked health administrative data; all data were collected prospectively. Participants were followed from the latter of their first multiple sclerosis clinic visit, 18th birthday or 1 January 1996; until death, emigration or 31 December 2013. Only those who were naïve to disease-modifying therapy and immunosuppressant treatment of multiple sclerosis at the start of their follow-up were included in the analysis. A nested case-control approach was used. Up to 20 controls, matched to cases (deaths) by country, sex, age ± 5 years, year and disability level at study entry, were randomly selected from the cohort by incidence density sampling. The associations between all-cause mortality and at least 6 months beta interferon exposure, and also cumulative exposure ('low', 6 months to 3 years; and 'high', >3 years), were estimated by conditional logistic regression adjusting for treatment with other disease-modifying therapies and age in years. Further analyses included separate analyses by sex and country, additional adjustment for comorbidity burden in the Canadian cohort, and estimation of the association between beta interferon and multiple sclerosis-related death in both countries. Among 5989 participants (75% female) with a mean age of 42 (standard deviation, SD 11) years at study entry, there were 742 deaths (70% female) and the mean age at death was 61 (SD 13) years. Of these cases, 649 were matched to between one and 20 controls. Results of the conditional logistic regression analyses are expressed as adjusted odds ratios with 95% confidence intervals. The odds of beta interferon exposure were 32% lower among cases than controls (0.68; 0.53-0.89). Increased survival was associated with >3 years beta interferon exposure (0.44; 0.30-0.66), but not between 6 months and 3 years exposure (1.00; 0.73-1.38). Findings were similar within sex and country, and for multiple sclerosis-related death. Beta interferon treatment was associated with a lower mortality risk among people with relapsing-onset multiple sclerosis. Findings were consistent between two geographically distinct regions in North America and Europe.

Predicting risk of secondary progression in multiple sclerosis: A nomogram.

OBJECTIVES: We aimed at designing a nomogram, a prediction tool, to predict the individual's risk of conversion to secondary progressive multiple sclerosis (SPMS) at the time of multiple sclerosis (MS) onset. METHODS: One derivation and three validation cohorts were established. The derivation cohort included 8825 relapsing-onset MS patients in Sweden. A nomogram was built based on a survival model with the best statistical fit and prediction accuracy. The nomogram was validated using data from 3967 patients in the British Columbia cohort, 176 patients in the ACROSS and 2355 patients in FREEDOMS/FREEDOMS II extension studies. RESULTS: Sex, calendar year of birth, first-recorded Expanded Disability Status Scale (EDSS) score, age at the first EDSS and age at disease onset showed significant predictive ability to estimate the risk of SPMS conversion at 10, 15 and 20 years. The nomogram reached 84% (95% confidence intervals (CIs): 83-85) internal and 77% (95% CI: 76-78), 77% (95% CI: 70-85) and 87% (95% CI: 84-89) external accuracy. CONCLUSIONS: The SPMS nomogram represents a much-needed complementary tool designed to assist in decision-making and patient counselling in the early phase of MS. The SPMS nomogram may improve outcomes by prompting timely and more efficacious treatment for those with a worse prognosis.

Five years before multiple sclerosis onset: Phenotyping the prodrome.

BACKGROUND: The multiple sclerosis (MS) prodrome is poorly characterized. OBJECTIVE: To phenotype the MS prodrome via health care encounters. METHODS: Using data from a population-based cohort study linking administrative and clinical data in four Canadian provinces, we compared physician and hospital encounters and prescriptions filled (via International Classification of Diseases chapters, physician specialty or drug classes) for MS subjects in the 5 years before the first demyelinating claim in an administrative cohort or the clinical symptom onset in an MS clinic-derived cohort, to age-, sex- and geographically matched controls. Rate ratios (RRs), 95% confidence intervals (95% CIs) and proportions were estimated. RESULTS: The administrative and clinical cohorts included 13,951/66,940 and 3202/16,006 people with and without MS (cases/controls). Compared to controls, in the 5 years before the first demyelinating claim or symptom onset, cases had more physician and hospital encounters for the nervous (RR (range) = 2.31; 95% CI: 1.05-5.10 to 4.75; 95% CI: 3.11-7.25), sensory (RR (range) = 1.40; 95% CI: 1.34-1.46 to 2.28; 95% CI: 1.72-3.02), musculoskeletal (RR (range) = 1.19; 95% CI: 1.07-1.33 to 1.70; 95% CI: 1.57-1.85) and genito-urinary systems (RR (range) = 1.17; 95% CI: 1.05-1.30 to 1.59; 95% CI: 1.48-1.70). Cases had more psychiatrist and urologist encounters (RR (range) = 1.48; 95% CI: 1.36-1.62 to 1.80; 95% CI: 1.61-2.01), and higher proportions of musculoskeletal, genito-urinary or hormonal-related prescriptions (1.1-1.5 times higher, all p < 0.02). However, cases had fewer pregnancy-related encounters than controls (RR = 0.78; 95% CI: 0.71-0.86 to 0.88; 95% CI: 0.84-0.92). CONCLUSION: Phenotyping the prodrome 5 years before clinical recognition of MS is feasible.

Disease-modifying drugs for multiple sclerosis and infection risk: a cohort study.

OBJECTIVE: Little is known about disease-modifying treatments (DMTs) for multiple sclerosis (MS) and infection risk in clinical practice. We examined the association between DMTs and infection-related medical encounters. METHODS: Using population-based administrative data from British Columbia, Canada, we identified MS cases and followed them from their first demyelinating event (1996-2013) until emigration, death or study end (December 2013). Associations between DMT exposure (by DMT generation or class) and infection-related physician or hospital claims were assessed using recurrent time-to-events models, adjusted for age, sex, socioeconomic status, index year and comorbidity count. Results were reported as adjusted HRs (aHRs). RESULTS: Of 6793 MS cases, followed for 8.5 years (mean), 1716 (25.3%) were DMT exposed. Relative to no DMT, exposure to any first-generation DMT (beta-interferon or glatiramer acetate) was not associated with infection-related physician claims (aHR: 0.96; 95% CI 0.89 to 1.02), nor was exposure to these drug classes when assessed separately. Exposure to any second-generation DMT (oral DMT or natalizumab) was associated with an increased hazard of an infection-related physician claim (aHR: 1.47; 95% CI 1.16 to 1.85); when assessed individually, the association was significant for natalizumab (aHR: 1.59; 95% CI 1.19 to 2.11) but not the oral DMTs (aHR: 1.17; 95% CI 0.88 to 1.56). While no DMTs were associated with infection-related hospital claims, these hospitalisations were also uncommon. CONCLUSION: Exposure to first-generation DMTs was not associated with an altered infection risk. However, exposure to the second-generation DMTs was, with natalizumab associated with a 59% increased risk of an infection-related physician claim. Continued pharmacovigilance is warranted, including an investigation of the DMT-associated infection burden on patient outcomes.

Infection-related health care utilization among people with and without multiple sclerosis.

BACKGROUND: Little is known about infection risk in multiple sclerosis (MS). OBJECTIVE: We examined infection-related health care utilization in people with and without MS. METHODS: Using population-based health administrative data from British Columbia, Canada, people with MS were followed from their first demyelinating claim (1996-2013) until death, emigration, or study end (2013). Infection-related hospital, physician, and prescription data of MS cases were compared with sex-, age-, and geographically matched controls using adjusted regression models. Sex and age differences (18-39, 40-49, 50-59, 60+ years) were explored. RESULTS: Relative to 35,837 controls, 7179 MS cases were over twice as likely to be hospitalized for infection (adjusted odds ratio: 2.39; 95% confidence interval (CI): 2.16-2.65), had 41% more physician visits (adjusted rate ratio (aRR): 1.41; 95% CI: 1.36-1.47), and filled 57% more infection-related prescriptions (aRR: 1.57; 95% CI: 1.49-1.65). Utilization was disproportionately higher in MS men than women and was elevated across all ages. MS cases had nearly twice as many physician visits and two to three times more hospitalizations for pneumonia, urinary system infections, and skin infections (aRRs ranged from 1.6 to 3.3) and over twice as many hospitalizations for intestinal infections (aRR = 2.6) and sepsis (aRR = 2.2). CONCLUSION: Infection-related health care utilization was increased in people with MS across all age groups, with a higher burden for men.

Age Related Multiple Sclerosis Severity Score: Disability ranked by age.

BACKGROUND: The Multiple Sclerosis Severity Score (MSSS) is obtained by normalising the Expanded Disability Status Scale (EDSS) score for disease duration and has been a valuable tool in cross-sectional studies. OBJECTIVE: To assess whether use of age rather than the inherently ambiguous disease duration was a feasible approach. METHOD: We pooled disability data from three population-based cohorts and developed an Age Related Multiple Sclerosis Severity (ARMSS) score by ranking EDSS scores based on the patient's age at the time of assessment. We established the power to detect a difference between groups afforded by the ARMSS score and assessed its relative consistency over time. RESULTS: The study population included 26058 patients from Sweden ( n = 11846), Canada ( n = 6179) and the United Kingdom ( n = 8033). There was a moderate correlation between EDSS and disease duration ( r = 0.46, 95% confidence interval (CI): 0.45-0.47) and between EDSS and age ( r = 0.44, 95% CI: 0.43-0.45). The ARMSS scores showed comparable power to detect disability differences between groups to the updated and original MSSS. CONCLUSION: Since age is typically unbiased and readily obtained, and the ARMSS and MSSS were comparable, the ARMSS may provide a more versatile tool and could minimise study biases and loss of statistical power caused by inaccurate or missing onset dates.

Adherence to disease-modifying therapies for multiple sclerosis and subsequent hospitalizations.

PURPOSE: The aim of this study was to examine the association between optimal adherence to first-line disease-modifying therapies (DMT) for multiple sclerosis (MS) and hospitalizations. METHODS: We used population-based administrative data from three Canadian provinces. All individuals receiving DMT (interferon-B-1b, interferon-B-1a, or glatiramer acetate) between January 1, 1996, and December 31, 2011 (British Columbia); March 31, 2012 (Manitoba); or March 31, 2014, (Saskatchewan) were included. Adherence was estimated for the first year of DMT (year 0), using the medication possession ratio (MPR). The association between optimal adherence (MPR ≥ 80%) and all-cause and MS-specific hospitalizations in the subsequent 1, 2, and 5 years was assessed using Hurdle Poisson and logistic regression. Rate and odds ratios were adjusted (aRR and aOR) for sociodemographic factors and prior health-care utilization. RESULTS: Overall, 4746 subjects were followed for a mean 7.8 (SD 4.0) years; 3598 (76%) were women. Optimal DMT adherence was achieved in 3564/4746 (75.1%) subjects. Subsequent all-cause and MS-specific hospitalizations were lower for subjects with optimal versus suboptimal adherence, but none reached statistical significance (1-year period, aRR = 0.77, 95%CI: 0.47-1.26; aOR = 0.80, 95%CI: 0.52-1.25). Similar findings were observed in the 2-year and 5-year periods. Prior health-care utilization (hospitalizations and medications) was associated with future hospitalizations; for every additional medication class, the 5-year all-cause hospitalization rate and likelihood of an MS-specific hospitalization increased by 5% and 11%, respectively (aRR = 1.05, 95%CI: 1.02-1.07; and aOR = 1.11, 95%CI: 1.07-1.14). CONCLUSIONS: Hospitalization rates were lower in subjects with optimal DMT adherence, but findings were not statistically significant. Prior hospitalization and polypharmacy were associated with increased risk for future hospitalizations in MS. Copyright © 2017 John Wiley & Sons, Ltd.