Association between use of interferon beta and progression of disability in patients with relapsing-remitting multiple sclerosis

Afsaneh Shirani, Yinshan Zhao, Mohammad Ehsanul Karim, Charity Evans, Elaine Kingwell, Mia L. Van Der Kop, Joel Oger, Paul Gustafson, John Petkau, Helen Tremlett

Research output: Contribution to journalArticle

198 Scopus citations

Abstract

Context: Interferon beta is widely prescribed to treat multiple sclerosis (MS); however, its relationship with disability progression has yet to be established. Objective: To investigate the association between interferon beta exposure and disability progression in patients with relapsing-remitting MS. Design, Setting, and Patients: Retrospective cohort study based on prospectively collected data (1985-2008) from British Columbia, Canada. Patients with relapsing-remitting MS treated with interferon beta (n=868) were compared with untreated contemporary (n=829) and historical (n=959) cohorts. Main Outcome Measures: The main outcome measure was time from interferon beta treatment eligibility (baseline) to a confirmed and sustained score of 6 (requiring a cane to walk 100 m; confirmed at >150 days with no measurable improvement) on the Expanded Disability Status Scale (EDSS) (range, 0-10, with higher scores indicating higher disability). A multivariable Cox regression model with interferon beta treatment included as a time-varying covariate was used to assess the hazard of disease progression associated with interferon beta treatment. Analyses also included propensity score adjustment to address confounding by indication. Results: The median active follow-up times (first to last EDSS measurement) were as follows: for the interferon beta-treated cohort, 5.1 years (interquartile range [IQR], 3.0-7.0 years); for the contemporary control cohort, 4.0 years (IQR, 2.1-6.4 years); and for the historical control cohort, 10.8 years (IQR, 6.3-14.7 years). The observed outcome rates for reaching a sustained EDSS score of 6 were 10.8%, 5.3%, and 23.1% in the 3 cohorts, respectively. After adjustment for potential baseline confounders (sex, age, disease duration, and EDSS score), exposure to interferon beta was not associated with a statistically significant difference in the hazard of reaching an EDSS score of 6 when either the contemporary control cohort (hazard ratio, 1.30; 95% CI, 0.92-1.83; P=.14) or the historical control cohort (hazard ratio, 0.77; 95% CI, 0.58-1.02; P=.07) were considered. Further adjustment for comorbidities and socioeconomic status, where possible, did not change interpretations, and propensity score adjustment did not substantially change the results. Conclusion: Among patients with relapsing-remitting MS, administration of interferon beta was not associated with a reduction in progression of disability.

Original languageEnglish (US)
Pages (from-to)247-256
Number of pages10
JournalJAMA - Journal of the American Medical Association
Volume308
Issue number3
DOIs
StatePublished - Jul 18 2012
Externally publishedYes

ASJC Scopus subject areas

  • Medicine(all)

Fingerprint Dive into the research topics of 'Association between use of interferon beta and progression of disability in patients with relapsing-remitting multiple sclerosis'. Together they form a unique fingerprint.

  • Cite this

    Shirani, A., Zhao, Y., Karim, M. E., Evans, C., Kingwell, E., Van Der Kop, M. L., Oger, J., Gustafson, P., Petkau, J., & Tremlett, H. (2012). Association between use of interferon beta and progression of disability in patients with relapsing-remitting multiple sclerosis. JAMA - Journal of the American Medical Association, 308(3), 247-256. https://doi.org/10.1001/jama.2012.7625