Shared scheme for assessing drugs for multiple sclerosis :Dealing with uncertainties about cost effectiveness of treatments is difficult problemBMJ 2003; 326 doi: https://doi.org/10.1136/bmj.326.7400.1212-a (Published 29 May 2003) Cite this as: BMJ 2003;326:1212
All rapid responses
Re: Shared scheme for assessing drugs for multiple sclerosis and
measurement of outcome
Professors Chadwick and Gray  repeat the often stated ‘fact’ that
“there are no obviously better alternatives to the expanded disability
status score” for use in studies of multiple sclerosis, especially disease
modifying drugs. This ignores the evidence.
The expanded disability status score (EDSS) can be faulted on many
grounds. It is resource-expensive, requiring a full neurological
examination if undertaken according to its derivation. It mixes different
levels of disease effect, with items from the impairment level (i.e.
symptoms and signs) and the activity level (i.e. mobility), which is
invalid. As a measure of mobility it is insensitive and unreliable,
especially as estimates of walking distance are themselves unreliable .
More importantly there is good evidence that other measures are
better. For example the Rivermead Mobility Index (RMI) and gait speed
both are better at detecting change , and simple measures of dexterity
are also more sensitive to change . Further there are some MS specific
measures such as the Guy’s Neurological Disability Scale (GNDS) which have
also been found to be valid, reliable and sensitive to change .
There are few remaining arguments to support continued use of the
EDSS. Neurologists are undoubtedly familiar with the EDSS, but they can
learn new measures and unless all change is stopped this is not an
adequate reason. A common measure facilitates comparison of studies and
meta-analysis, but meta-analysis would be less necessary with more
sensitive measures, and protocols for allowing EDSS data and data from
other measures to be compared and combined could easily be developed.
Finally regulatory authorities may ‘insist’ that the EDSS is used,
but the solution is to educate them that better measures exist, and not
simply to accept this ‘insistence’ which probably arises from ignorance
and constantly reading that “there are no obviously better alternatives to
the expanded disability status score”!
I would therefore strongly recommend that future studies use one or
more of the many better measures that exist, and in the absence of any
consensus I would commend the Rivermead Mobility Index (which is free to
anyone, available in several languages, and can be completed in a few
1 Chadwick D, Gray R. Shared scheme for assessing drugs for multiple sclerosis: Dealing
with uncertainties about cost effectiveness of treatments is difficult
2 Giantomaso T, Makowsky L, Ashworth N, Sankaran R. The validity of patient and physician estimates of walking distance.
Clinical Rehabilitation 2003;17:394-401
3 Vaney C., Blaurock H., Gattlen B., Meisels C
Assessing mobility in Multiple Sclerosis using the Rivermead Mobility
Index and gait speed.
Clinical Rehabilitation 1996;10:216-226.
4 Goodkin E, Herstgaard D, Seminary J. Upper extremity function in multiple sclerosis: improving sensitivity
with box and block and nine hole pegs tests.
Archives of Physical Medicine and Rehabilitation 1988;69:850-854
5 Rossier P, Wade DT. The Guy’s Neurological Disability Scale in patients with multiple
sclerosis: a clinical evaluation of its reliability and validity.
Clinical Rehabilitation 2002;16:75-95
6 Wade DT, Young C, Chaudhuri KR, Davidson DL. A randomized placebo controlled exploratory study of Vitamin B-12,
lofepramine and L-phenylalanine (the “Cari Loder regime”) in the treatment
of multiple sclerosis.
Journal of Neurology, Neurosurgery and Psychiatry 2002;73:246-49
No commercial interests, but I was involved in developing or studying some of the measures recommended.
Competing interests: No competing interests