"Our study demonstrates that the longer the duration of MS and the lower the disability, the more likely a patient is to remain stable and not progress to a greater level of disability," says Sean Pittock, M.D., lead author of the paper. "This isn't a small issue; it's a big issue."
Moses Rodriguez, M.D., Mayo Clinic neurologist and senior author of the paper, adds, "The documentation of benign MS does exist, and this condition can be identified during an analysis of the patient at even five years with MS."
The investigators propose a definition of benign MS as patients who have MS for 10 years or more who have an Expanded Disability Status Scale (EDSS) score of 2 or less, because they have less than 10 percent likelihood of developing significant disability in the future. The EDSS quantifies the amount of disability in MS patients from zero (normal neurological exam) to 10 (death due to MS). On this scale, a score of 2 indicates minimal disability, 4 indicates moderate disability but able to walk unassisted, 6 indicates requirement of an aid or cane to walk, and 8 indicates need for a wheelchair.
Patients who have benign MS can have ongoing attacks, but they do not accrue any disability from the attacks, says Dr. Rodriguez. "You have symptoms, but they go away, and if they come back, they go away again, typically after a week or so. You might have a bad week or an attack -- like the loss of vision in one eye -- but you completely recover. Most of the time, however, there would be no outward sign of the disease, and the patients themselves would say that they are normal."
Drs. Pittock, Rodriguez and colleagues found that only 7 percent of patients who had minimal or no disability (EDSS score equal to or less than 2) after 10 years with MS progressed to a greater level of disability (EDSS score greater than 4), and none needed a wheelchair after 20 years with MS. However, for those MS patients studied who had an EDSS score of 2.5 to 4 after 10 years of the disease, 12 of 21 patients' disabilities increased to a score greater than 4 after 20 years with the disease.
Another Mayo Clinic neurologist and author, Brian Weinshenker, M.D., says of the study: "This confirms some other studies, but it flies in the face of the commonly held belief that MS is never benign and that every person should be started on lifelong interferon therapy before we get a feel of how the natural course of their illness will behave."
The investigators indicate that this news is particularly important for patients who have had benign MS for 10 years or longer, for whom physicians can make a reasonable prediction that they will not develop progressive disability. However, forecasting the course of a patient's MS prior to the five-year mark remains difficult, the investigators indicate.
These findings have potential impact for the 17 percent of all U.S. multiple sclerosis patients who have benign disease. Dr. Rodriguez indicates that this percentage represents as many as approximately 70,000 benign MS patients, assuming the total of MS patients in the United States to be 400,000.
The current approach prevalent in the MS treatment community to prescribing drugs for MS patients is "the earlier the better," according to Drs. Rodriguez and Pittock. "There is an overwhelming drive to start all patients with a diagnosis of MS on immunomodulatory medications," says Dr. Pittock.
However, the Mayo Clinic study calls this drive into question. "This study raises questions about the current dogma out there that all patients should be started on medications as soon as possible," says Dr. Rodriguez. "If we treat everyone early, we would treat some people who never needed treatment. And, if they don't need treatment, we can save society hundreds of millions of dollars, and the patients with benign MS can avoid major side effects."
Dr. Rodriguez elaborates on the costs, monetary and physical, of prescribing medications to MS patients who may turn out to have benign disease. "Medications are expensive, about $10,000 per year," he says. "The injections [of immunomodulatory medications] are painful, and they cause side effects like nausea, vomiting, fatigue, and achiness. You may have to lie down in bed for the day. It can be like having the flu every day of your life. In addition, the drugs are only partly effective, and their effectiveness over the long course of the disease has not been demonstrated."
Mayo Clinic Department of Neurology's philosophy in working with MS patients is to share the therapeutic decision-making process between physician and patient, weighing the pros and cons of starting medication with the predictive data on hand, as well as the patient's personality and personal wishes, to arrive at a customized determination of appropriate treatment for each patient. The investigators on this study believe that their findings will be helpful in this process.
Though the concept of benign MS is not new, the study represented in August Annals of Neurology manuscript is the most extensive population study of MS to date, says Dr. Rodriguez. The Olmsted County population of MS patients has been studied since 1905. The study included all people in the population, not just those who sought a doctor for MS. This is notable in that patients who have benign MS may not seek medical attention.
For MS patients who have concerns or questions regarding whether they have benign MS or whether they should be on immunomodulatory medications, Dr. Rodriguez stresses that it is important for them to contact their personal physicians to discuss their diseases and make decisions customized to their personal situations.
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Annals of Neurology