© 2010 American Academy of Neurology
Vascular comorbidity is associated with more rapid disability progression in multiple sclerosis
R.A. Marrie, MD, PhD, R. Rudick, MD, R. Horwitz, MD, G. Cutter, PhD, T. Tyry, PhD, D. Campagnolo, MD and T. Vollmer, MD
From the Department of Medicine (R.A.M.), University of Manitoba, Winnipeg, Canada; Neurological Institute (R.R.), Cleveland Clinic, Cleveland, OH; Department of Medicine (R.H.), Stanford University, Stanford, CA; Department of Biostatistics (G.C.), University of Alabama at Birmingham; and Division of Neurology (T.T., D.C., T.V.), Barrow Neurological Institute, Phoenix, AZ.
Address correspondence and reprint requests to Dr. Ruth Ann Marrie, Health Sciences Center, GF-533, 820 Sherbrook Street, Winnipeg, MB R3A 1R9, Canada email@example.com
Background: Vascular comorbidity adversely influences health outcomes in several chronic conditions. Vascular comorbidities are common in multiple sclerosis (MS), but their impact on disease severity is unknown. Vascular comorbidities may contribute to the poorly understood heterogeneity in MS disease severity. Treatment of vascular comorbidities may represent an avenue for treating MS.
Methods: A total of 8,983 patients with MS enrolled in the North American Research Committee on Multiple Sclerosis Registry participated in this cohort study. Time from symptom onset or diagnosis until ambulatory disability was compared for patients with or without vascular comorbidities to determine their impact on MS severity. Multivariable proportional hazards models were adjusted for sex, race, age at symptom onset, year of symptom onset, socioeconomic status, and region of residence.
Results: Participants reporting one or more vascular comorbidities at diagnosis had an increased risk of ambulatory disability, and risk increased with the number of vascular conditions reported (hazard ratio [HR]/condition for early gait disability 1.51; 95% confidence interval [CI] 1.41–1.61). Vascular comorbidity at any time during the disease course also increased the risk of ambulatory disability (adjusted HR for unilateral walking assistance 1.54; 95% CI 1.44–1.65). The median time between diagnosis and need for ambulatory assistance was 18.8 years in patients without and 12.8 years in patients with vascular comorbidities.
Conclusions: Vascular comorbidity, whether present at symptom onset, diagnosis, or later in the disease course, is associated with a substantially increased risk of disability progression in multiple sclerosis. The impact of treating vascular comorbidities on disease progression deserves investigation.
Abbreviations: EDSS = Expanded Disability Status Scale; HR = hazard ratio; MS = multiple sclerosis; NARCOMS = North American Research Committee on Multiple Sclerosis; PDDS = Patient Determined Disease Steps.
Study funding: Supported in part by the NIH, National Institute of Child Health and Human Development, and Multidisciplinary Clinical Research Career Development Program Grant K12 HD04909. The NARCOMS Registry is supported by the Consortium of Multiple Sclerosis Centers.
Disclosure: Author disclosures are provided at the end of the article.
Received September 17, 2009. Accepted in final form January 6, 2010.
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Online ISSN: 1526-632X
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