(HealthDay News) – Interferon beta does not reduce the progression of disability in patients with relapsing-remitting multiple sclerosis (MS), according to a study published in the July 18 issue of the Journal of the American Medical Association.

To examine the correlation between interferon beta use and disability progression in relapsing-remitting MS, Afsaneh Shirani, MD, from the Vancouver Coastal Health Research Institute in Canada, and colleagues analyzed data collected from 868 patients with relapsing-remitting MS in Canada treated with interferon beta and compared them with 829 untreated contemporary and 959 historical controls. The Expanded Disability Status Scale (EDSS) was used to assess disability (range, 0–10, with higher scores indicating higher disability).

The researchers found that the median active follow-up times were 5.1 years for the interferon beta-treated cohort, 4 years for the contemporary control cohort, and 10.8 years for the historical control cohort. The observed rates for the three cohorts reaching a sustained EDSS score of 6 (requiring a cane to walk 100m) were 10.8%, 5.3%, and 23.1%, respectively. After adjusting for potential baseline confounding variables, exposure to interferon beta was not associated with a statistically significant difference in the hazard of reaching an EDSS score of 6 when either control group were considered. Neither further adjustment for comorbidities or socioeconomic variables nor propensity score adjustment changed the results.

“The ultimate goal of treatment for MS is to prevent or delay long-term disability,” the authors write. “Our findings bring into question the routine use of interferon beta drugs to achieve this goal in MS.”

Several of the authors disclosed financial ties to the pharmaceutical industry.

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