a new study finds, and there are big gaps in how they respond to disease-modifying therapies (DMTs).
Dr. Carlos Pérez
“Hispanics and African Americans develop a more severe disease course and accumulate more MS-related disability over time despite similar sociodemographic backgrounds and similar patterns of DMT use throughout their disease, suggesting that socioeconomic status and access to health care may not be the main determinants of health,” said neurologist Carlos Pérez, MD, of the University of Texas Health Science Center, Houston. He spoke at the annual meeting held by the Americas Committee for Treatment and Research in Multiple Sclerosis and in a follow-up interview.
“In addition,” Dr. Pérez said, “therapeutic responses to individual DMTs, as well as tolerance and side-effect profiles, are also variable among racial/ethnic groups.”
The researchers tracked 150 patients with MS at the University of Texas Health Science Center – 50 Whites, 50 African American, and 50 Hispanic – who were age and gender matched. The average age of the subjects was 45, and 74% of those in each group were women.
While educational levels between the groups were similar, African Americans had a much higher rate of lost employment because of disability (38%) than Hispanics (19%) and Whites (15%, P = .02). Fifty-seven patients (38%) needed escalation of therapy, and 63% were African American.
About 30% of subjects switched DMTs because of intolerance/adverse events, and 47% of those were African American. Interferons most commonly caused adverse effects in African Americans (61%), and Whites were the most likely to not tolerate glatiramer acetate (39%) than Hispanics (8%) and African Americans (13%).
What might be behind the disparities? “It is possible that genetic factors may play a greater role than previously thought. A recent study reported that Hispanic and African American patients with MS have higher levels of peripheral blood plasmablasts, which may provide indirect evidence for potential biological mechanisms underlying racial and clinical disparities in MS,” Dr. Pérez said. “These mechanisms appear to involve higher degrees of inflammation in the central nervous system. This may explain why African Americans may respond better to higher-efficacy therapies initially, when inflammatory processes predominate MS-related pathology, rather than at later stages of the disease when inflammation plays a less prominent role. Neurologists should consider higher-efficacy DMT as first line. We have begun to do this in our practice.”
Dr. Pérez said the findings offer other lessons. “Neurologists should consider that Caucasian patients tolerate glatiramer acetate less frequently, compared with other racial groups, and potentially consider using alternative DMTs unless the benefits outweigh the risks, such as during pregnancy.”
He also noted that African Americans treated with oral DMTs at baseline were more likely to develop worsening disability over time. “This argues in favor of infusion therapies as first-line treatment,” he said, adding that more Hispanics with MS were not on treatment – or discontinued treatment – compared with Whites and African Americans.