Oslo University Hospital
Oslo Centre for Biostatistics and Epidemiology

Author Of 1 Presentation

Epidemiology Poster Presentation

P0502 - The Natural Course of Multiple Sclerosis Rewritten: A Population Based Study on Disease Demographics and Progression (ID 758)

Speakers
Presentation Number
P0502
Presentation Topic
Epidemiology

Abstract

Background

Over the past few decades there has been an improvement in the rate of disability progression in multiple sclerosis (MS) patients, and most studies relate this evolvement to the introduction of disease modifying therapies. However, several other factors have changed over this period, including access to improved MRI and newer diagnostic criteria

Objectives

To investigate changes in the natural course of MS over time in a near-complete and geographically well-defined population from the south-east of Norway.

Methods

This is a registry-based study. We examined disease progression over two decades and assessed the effect of disease modifying therapies using linear mixed-effect models.

Results

In a cohort of 2097 patients we found a significant improvement in disability as measured by the Expanded Disability Status Scale (EDSS) stratified by age, and the improvement remained significant after adjusting for time on disease modifying medications, gender and progressive MS at onset. The time from disease onset to EDSS 6 in the total cohort was 29.8 years (95% CI 28.5-31.1) and was significantly longer in patients diagnosed after 2006 compared to patients diagnosed before. In addition, we found significant differences between patient demographics, as well as time to EDSS 6 in the near-complete, geographically well-defined population compared to the rest of the cohort from Oslo and its affluent suburbs.

Conclusions

The natural course of MS is improving, but the improvement seen in disease progression in the modern MS patient may have multifaceted explanations. This is supported by our findings of changing population demographics with patients being diagnosed earlier in the disease course, but also at an older age and with less severe disease. Our study underlines the fact that historical cohorts are unsuitable for comparison with modern cohorts in MS studies. We also found significant differences in demographics and time to EDSS 6 between our geographically near-complete population and the rest of the database with the cohort from Oslo and its wealthy suburbs, which means that studies done on incomplete populations should be interpreted with caution.

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