African-Americans 50% More Likely to Experience Significant Disability
By Annette M. Boyle
BALTIMORE — For decades, multiple sclerosis (MS) researchers have debated whether the disease-modifying therapies that reduce the number of relapses might also slow progression of the disease over the long term. A VA study indicates they probably do — at least for men.
The same study, presented at the 2015 Annual Meeting of the American Academy of Neurology, also found that black ethnicity and male sex were significant independent indicators of progression to disability.1
“When disease-modifying therapies were first introduced, it wasn’t clear that they had an effect on the long-term course of the disease,” said Walter Royal, III, associate director of research for the VA Multiple Sclerosis Center of Excellence-East and director of the Maryland Center for Multiple Sclerosis Treatment and Research. “It was thought that MS might progress at the same rate as in those patients not treated with the therapies.”
The study of 2,691 Gulf War-era veterans with MS found that the patients who stayed on disease-modifying therapies (DMT) developed less disability than those not taking the medications, according to study co-author W. Joel Culpepper, PhD, associate director of Epidemiology and Outcomes for the VA MS Center of Excellence-East and assistant professor at the University of Maryland School of Pharmacy.
Even after controlling for age, race and MS subtype, “the data clearly show less disability in a 10- to 15-year timeframe,” Culpepper told U.S. Medicine.
That is good news for the VA’s 38,000 MS patients and others with the disease. “What sets these therapies apart from immunosuppressant therapies that are also used in MS is that suppressing the immune system has some serious detrimental consequence,” Culpepper said. “This shows patients receive real benefit from less-potent disease-modifying therapies.”
Slowing of Progression
Also encouraging, according to Culpepper and Royal, is that other recent clinical trials indicate that even patients who no longer have relapses but continue to worsen also see a slowing of progression. Other studies, however, have shown less-positive results.
“One study that looked at a drug used to treat primary-progressive MS did not show beneficial effect overall, but there was a suggestion that it was effective among males in the cohort,” Royal told U.S. Medicine. “The VA study was predominantly male. While findings were controlled for sex, it could be that a gender effect that was very potent could shine through.”
While MS affects about three times as many women as men and historically has been seen as a disease of individuals of Northern European descent, its incidence and prevalence have been increasing in racial groups and areas of the world previously unaffected.
That makes particularly notable the study’s finding that African-Americans were at greater risk for the disease and more likely to progress rapidly. African-American veterans in the study were 50% more likely to progress to Kurtzke Disability Status Scale (DSS) Level 6, using a cane, than other patients.
“The VA was among the first to show that rates of MS were higher among African-Americans than whites,” Culpepper said. A 2013 study by Annette Langer Gould, MD, at Kaiser found that black women, but not black men, had a significantly elevated risk of MS.2
“The biggest factor in the development of MS is likely related to vitamin D deficiency, which is associated with higher incidence of MS. African-Americans have lower vitamin D levels generally as a result of darker skin and low sun exposure,” Royal said. Other risk factors include obesity, diet, genetics and cigarette-smoke exposure.
In line with reports from elsewhere in the world, a study done at the University of Manitoba found a threefold increase in MS prevalence in Ontario during the past 20 years. “Part of the increase in prevalence comes from better management of the disease and related comorbidities so that people live longer. Fifty years ago, the life expectancy of MS patients was reduced by 10 to 15 years; today it’s five to seven years,” Culpepper said.
Improved imaging also allows physicians to detect abnormalities at a very early stage, often before any symptoms appear. “Clearly we’re better at recognizing and diagnosing MS, but that doesn’t account for the whole increase we’re seeing,” Culpepper added. “It raises questions about the physiology of the disease; we’re still grappling with defining what those factors are.”
Whatever accounts for the recent increase in the disease’s prevalence, Royal noted that the research indicates, “the risks are greater now and on the rise. In African-Americans, there’s a more-aggressive disease course, and it’s critical to get on therapy to garner as much benefit as possible and to slow disease progression.”
With more patients on therapy, it might also be easier to determine which treatments work better for which patient subgroups. That research could guide clinicians seeking to select the most-appropriate and effective therapy earlier in the course of the disease, VA clinicians said.
Even without a “cookbook” to help in medication choice, starting therapy right away provides significant benefits to MS patients. “There was an old phrase about MS — ‘diagnose and adios.’ Not much could be done,” said Culpepper. “Now we know it is very important to start on therapy. We can see where treatment affects the course of the disease in our study; but, even if you held to the argument that therapy is only good for reducing disease activity, it still greatly improves patient’s quality of life.”
1 Wallin M, Culpepper WJ, Kurtzke J. Risk Factors for Disease Progression in a Diverse U.S. Population-based Multiple Sclerosis Cohort. Neurology. April 6, 2015;84(14):S45.003.
2 Langer-Gould A, Brara SM, Beaber BE, Zhang JL. Incidence of multiple sclerosis in multiple racial and ethnic groups. Neurology. 2013 May 7;80(19):1734-9. doi: 10.1212/WNL.0b013e3182918cc2. PubMed PMID: 23650231.