NEW YORK (Reuters Health) - Some people with multiple sclerosis (MS) have bouts of symptoms that are followed by periods of remission, while others suffer a more rapid worsening of the disease.
Now, study findings suggest that once a certain level of disability is reached, the time course of the illness is pretty much the same for all patients. At that point, drugs that cut down on symptom flare-ups may not delay disability in the long run, according to a report in the November 16th issue of The New England Journal of Medicine.
A chronic disease of the central nervous system, multiple sclerosis involves the destruction of myelin, the protective insulation around nerve fibers in the brain and spine. This breakdown causes symptoms such as numbness, coordination problems, and muscle weakness and stiffness.
In the current study, Dr. Christian Confavreux of the Hopital Neurologique in Lyons, France, and colleagues looked at 1,562 patients with the relapsing-remitting type of MS, which is characterized by episodes of fatigue and other neurological symptoms followed by symptom-free periods. They also looked at 282 patients with progressive type of MS, in which symptoms rapidly worsen with no letting up of the disease course.
The investigators found that patients who had relapsing-remitting symptoms took longer than 11 years to reach the point where they could walk no more than 500 meters (0.3 miles, or 1,640 feet) without resting. Those with the progressive form of the disease, however, reached that point in less than a year.
After that level of disability was reached, however, it took both groups about 5 to 6 years to get to the point that they could walk no more than 100 meters (328 feet) without resting, and 12 years to get to the point where they needed to rest after walking 10 meters (32 feet).
This, according to the researchers, suggests that preventing MS relapses in the short term may have little effect on long-term disability.
However, Confavreux and colleagues note, only a small number of patients in the study were receiving interferon beta--a drug class that in the last few years has been shown to cut MS relapses and delay disability.
SOURCE: The New England Journal of Medicine 2000;343:1430-1438.