Summary
A UBC research team collected on all MS patients with definite MS registered with an MS clinic in British Columbia between 1980 and 2004 (follow up to 2009) from the British Columbian MS database to examine naturally occurring improvements in disability scores (EDSS). The team observed improvements and sustained improvements in EDSS scores at one and two year intervals in people who were not treated with disease-modifying therapies. This finding suggests that more work is required to understand the underlying pathophysiology of MS, and the potential for therapeutic options geared at enhancing and prolonging this natural improvement. [Helen Tremlett, Feng Zhu, John Petkau, Joel Oger, Yinshan Zhao and the BC MS Clinic Neurologists. Mult Scler published online 26 June 2012. DOI: 10.1177/1352458512439119]
Details
UBC researchers collected a total of 16,132 EDSS scores (7653 yearly and 5845 biennial scores). Of the 7653 yearly EDSS intervals examined from 2961 patients, 14.9% showed an improvement (≥0.5 change in EDSS), 8.3% a ≥1 point and 2.2% a ≥2 point improvement. Corresponding declining scores were 32.9%, 20.5% and 7.9%, respectively. In fifty-three per cent of the intervals there was no observed change from one year to the next.
Certain characteristics were found to increase the likelihood of improvement in EDSS score including: female sex, younger age, shorter disease duration, relapsing–remitting disease at onset, the presence of moderate disability (compared with mild or advanced) and a previous episode of worsening (not associated with a relapse). However, a wide range of participants experienced periods of improvement including those who were previously stable and those with primary-progressive MS.
Those who were older and had longer disease duration had less likelihood of improvement, and primary-progressive MS was associated with a lower odds of improvement as compared with a relapsing-onset disease course.
These findings have clinical implications where the objective of a clinical trial is to assess improvements in disability specifically related to an investigational drug treatment. Without a placebo or ‘untreated’ control group, researchers need to be aware that improvements can occur naturally, and may differ based on participant characteristics.