The outcome spectrum of multiple sclerosis: disability, mortality, and a cluster of predictors from onset.

Interest in the long-term natural history of multiple sclerosis (MS) is being revived, as disability endpoints become increasingly important with the advent of highly efficacious long range but potentially harmful drugs. MS had an increasingly benign course, probably due to better assessment and changing diagnostic criteria. Incidence cohorts reduce inclusion bias, capturing both extreme benign and severe cases. We conducted a 50-year follow-up of an incidence cohort of Gothenburg residents with MS onset in 1950-1964 (n = 254; 212 with an initial relapsing-remitting course and 42 with a monophasic course, diagnostic criteria according to Poser). Patients were followed longitudinally until censoring, death, or study termination in 2012 and evaluated using Kaplan-Meier estimates and Cox regression analysis. Median time to secondary progression was 15 years. Median time to EDSS6 and EDSS7 was 26 and 48 years (n = 254), respectively. The cumulative risk of reaching EDSS6 was 50% at 55 years of age and 80% at 80 years of age (n = 212). A score based on a cluster of clinical features at onset predicted secondary progression, EDSS6, EDSS7, and EDSS10 (hazard ratio 1.6-2.3 per score unit for women, 0.99-1.49 for men). This score predicted the disease course during five decades indirectly, by predicting time to secondary progression. Age at onset predicted the course in men, with 3-6% yearly increase in the risk of reaching disability milestones. The present incidence cohort provided hard outcome data in untreated patients over several decades.

Continuous prediction of secondary progression in the individual course of multiple sclerosis.

BACKGROUND: Prediction of the course of multiple sclerosis (MS) was traditionally based on features close to onset. OBJECTIVE: To evaluate predictors of the individual risk of secondary progression (SP) identified at any time during relapsing-remitting MS. METHODS: We analysed a database comprising an untreated MS incidence cohort (n=306) with five decades of follow-up. Data regarding predictors of all attacks (n=749) and demographics from patients (n=157) with at least one distinct second attack were included as covariates in a Poisson regression analysis with SP as outcome. RESULTS: The average hazard function of transition to SPMS was 0.046 events per patient year, showing a maximum at age 33. Three covariates were significant predictors: age, a descriptor of the most recent relapse, and the interaction between the descriptor and time since the relapse. A hazard function termed "prediction score" estimated the risk of SP as number of transition events per patient year (range <0.01 to >0.15). CONCLUSIONS: The insights gained from this study are that the risk of transition to SP varies over time in individual patients, that the risk of SP is linked to previous relapses, that predictors in the later stages of the course are more effective than the traditional onset predictors, and that the number of potential predictors can be reduced to a few (three in this study) essential items. This advanced simplification facilitates adaption of the "prediction score" to other (more recent, benign or treated) materials, and allows for compact web-based applications (http://msprediction.com).

A representative cohort of patients with non-progressive multiple sclerosis at the age of normal life expectancy.

Multiple sclerosis may have a non-progressive symptomatology for decades; however, it is not clear whether the disease activity may abate completely. We identified a cohort of patients, resident in Gothenburg at the time of disease onset, between the years 1950-64 (n = 307). These geographical and temporal restrictions, along with favourable conditions for a 'spider' epidemiological study, were optimal for an unbiased selection; this 15-year incidence cohort was essentially followed prospectively for 37-59 years after onset. The shortest follow-up time for patients without primary or secondary progression was 45 years. For patients with an initial relapsing-remitting course and multiple sclerosis diagnosis according to the Poser criteria (n = 202), the probability of non-progressive disease after 40 years was 22% (standard error 3.0%), and after 50 years it was 14% (standard error 3.2%). For attack onset including patients with possible multiple sclerosis, the corresponding probabilities after 40 and 50 years were 35% (standard error 3.3%) and 28% (standard error 3.5%), respectively. At the last follow-up in 2009-10, when patients reached the average age of the Swedish population life expectancy, only 13 patients from the multiple sclerosis diagnosis cohort, according to the Poser criteria, remained alive and non-progressive. Their annualized attack frequency diminished with time from 0.29 to 0.015. These patients had been functioning well socially. Nine patients had an Expanded Disability Status Scale score of 0-2.5, and four patients had a score of 3 or 3.5, with deficits dating back to attacks decades ago. Eight patients participated in a complete neuropsychological examination, which showed a slight difference (P < 0.01) concerning verbal memory and executive function compared to an age and socially matched reference group, whereas results for five other cognitive domains were within the normal range. Magnetic resonance images fulfilled the Barkhof-Tintoré criteria for multiple sclerosis in 10 of 11 patients, with conspicuously few subcortical lesions relative to extensive periventricular lesions and lesions extending from the inferior midline aspect of the corpus callosum. Prediction of the non-progressive stage was possible with moderate hazard ratios and low sensitivity. Early features that predicted a non-progressive course were complete remission of the onset attack, low or moderate initial relapse frequency and-when the patients with possible multiple sclerosis were included-dominating afferent symptoms. The clinical disease activity had abated in these 13 patients, with the caveat that transition to secondary progression continued to occur after four decades, albeit with decreasing risk.

Long-term follow up of patients with clinically isolated syndromes, relapsing-remitting and secondary progressive multiple sclerosis.

This paper extends on previous data on prognosis in multiple sclerosis (MS), to encompass the entire course of the disease. The first episode suggestive of MS [the clinically isolated syndrome (CIS)] was included as a starting point, and the speed of secondary progression as an end point. Primary progressive MS was not included. Unique preconditions, with one neurological service covering the Göteborg district, allowed for establishing a strictly population-based, essentially untreated 15-year incidence cohort of 308 MS patients who were followed for 25 years. Survival analysis was performed as Kaplan-Meyer graphs, and independent predictors were ascertained by Cox regression analysis. A matrix of several predictors and end points was created. From CIS, a higher risk of developing clinically definite MS (CDMS), secondary progressive course and Disability Status Scale 7 (DSS7) was predicted by efferent tract lesions. However, less than 25% had reached DSS7 25 years after CIS with pure afferent lesions or other favorable predictors. During the first five years, higher relapse frequency, as well as incomplete remission of early bouts, predicted higher risks of secondary progressive course and DSS7 during follow-up to 25 years. However, these early predictors were unable to predict the rate of progression, which seems to contain an element of the disease process unassociated with its early events. Only late predictors, such as a shorter time from onset to secondary progression (1-10 years) and a higher number of functional systems involved at onset of progression predicted a faster progression rate. Predictors from this study could be used to refine historically controlled trials.