Authors' objectives:

There are three main aims to the current report:

- to review existing natural history data

- to review existing epidemiology data

- to review modelling literature and outline the structure of a theoretical model, which could be developed and used in the future to reflect the course of multiple sclerosis (MS) in terms of disease progression, health utility and cost at different stages of the disease.

Authors' results and conclusions: Natural history of MS: The most commonly quoted physical and cognitive effects of the disease include: weakness, fatigue, ataxia, bladder complaints, bowel problems, sensory effects and visual impairment. The most supported tool for the grading of functional effects of MS is the (Expanded) Disability Status Scale ((E)DSS). The scale ranges from 1 (least severe) to 10 (death from MS). However, the scale is not ideal because there is a bias towards the physical effects of the disease (particularly ambulation) rather than the cognitive effects. Relapse rates in relapsing-remitting MS vary considerably over time for an individual and between individuals, but there is a general pattern of exacerbations of more frequent relapses, followed by long periods of lower rates. This makes assessment of the effects of treatments in an individual extremely problematic. High relapse rates at the onset of the disease give a limited prediction of poor prognosis. Epidemiology of MS: Epidemiological studies in England and Wales have given a range of prevalence estimates but the average is estimated at about 110 patients per 100,000 population. There is good international evidence of geographical variation in prevalence, best described by increasing prevalence with latitude (both north and south of the equator). This is not seen in the data for England and Wales, but this may be due to other causes of variation masking any trend in the limited data. If such a latitudinal variation did apply to England and Wales, then the prevalence would range from 104 to 156 per 100,000 (south to north), indicating substantial differences in resource consequences. Improved survival has led to increased prevalence.

Authors' recommendations: MS is a chronic disease of long duration affecting a wide range of human functions. Short research studies of treatment efficacy cannot fully assess meaningful outcomes nor deliver the information needed for health economic analyses. All MS patients should be better monitored throughout the course of the disease both to improve their care and to better understand the natural history of the disease. New methods need to be developed for researching treatments of chronic diseases. The development of a model of MS progression should incorporate information on costs and QoL at different stages of the disease in order to examine the long-term cost-effectiveness of any changes in progression.

Authors' methods: Review

Project Status: Completed

URL for project: http://www.hta.ac.uk/1164

Year Published: 2002

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: England, United Kingdom

Organisation Name: NIHR Health Technology Assessment programme

Contact Address: NIHR Journals Library, National Institute for Health and Care Research, Evaluation, Trials and Studies Coordinating Centre, Alpha House, University of Southampton Science Park, Southampton SO16 7NS, UK

Contact Name: journals.library@nihr.ac.uk

Contact Email: journals.library@nihr.ac.uk

Copyright: 2009 Queen's Printer and Controller of HMSO