In Multiple Sclerosis, Do Relapses Make Disability Worse?
Nov. 15, 2000 -- A controversial new study has found that patients with primary progressive multiple sclerosis become disabled faster than those with relapsing-remitting multiple sclerosis, which goes against the medical community's most widely accepted theory. However, the controversy comes from the finding that once both groups reach a certain level of disability, subsequent relapses don't alter the time it takes to reach progressively worse disability.
Early in the course of multiple sclerosis, most patients have attacks of neurologic symptoms that disappear as rapidly as they appear. Between relapses -- marked by vision loss, numbness, or weakness -- patients may appear and feel perfectly normal. But as this relapsing-remitting form of the disease progresses, recovery from these attacks is incomplete, eventually leaving the patient with complete disability.
About 15% of multiple sclerosis patients have a form of the disease called primary progressive, without clear-cut remissions during which symptoms improve, but with continuous deterioration to total disability.
"Relapses do not significantly influence the progression of irreversible disability" write the authors of the new study, published in the Nov. 16, 2000 issue of TheNew England Journal of Medicine.
"No practicing neurologist on the planet believes that," John Corboy, MD, who was not involved in the study, tells WebMD. "It's a question of what you look at to define disability, and how and when you look at relapses," says Corboy, an associate professor of neurology and director of the multiple sclerosis clinic at the University of Colorado Health Sciences Center in Denver.
"I don't think their conclusion is justified," Douglas R. Jeffery, MD, PhD, tells WebMD. Although progression of disability was clearly worse in patients whose disease was progressive from onset, that does not mean that progression was unrelated to relapses, says Jeffery, who also wasn't involved in the study.
According to Jeffery and Corboy, recent studies show that most patients do not make a complete recovery following relapses, and that disability gets progressively worse with each relapse. This is what doctors usually see in their practices, Jeffery says.
The new study looked at nearly 2,000 patients in a database for multiple sclerosis in Lyons, France. Researchers determined when each patient's symptoms began and relapses occurred, and measured progression of disability.
Because the researchers depended on the patients to report accurately on the progression of their disease, they looked at levels of disability that would be easy for the patients to remember -- their ability to walk. The patients rated themselves according to the distance they were able to walk, with a higher score meaning more disability.
It took longer for patients who started out with the relapsing-remitting form of the disease to reach higher scores than it did patients who had progressive disease from the outset. Yet once patients reached a certain level of disability, it took them the same amount of time to progress to a further level of disability -- regardless of which group they were in.