title: Examining the joint effect of disability, health behaviors, and comorbidity on mortality in MS.
abstract: BACKGROUND
  In multiple sclerosis (MS), comorbidities have been associated with disability progression and an increased risk of mortality. We investigated the association between comorbidities and mortality in MS after accounting for disability and health behaviors.
  
  
  METHODS
  We followed North American Research Committee on Multiple Sclerosis (NARCOMS) Registry participants who completed the Fall 2006 survey on comorbidities until death (reported or matched in the National Death Index) or date of last follow-up in 2014. We used proportional hazards regression to investigate the association between comorbidities and mortality, controlling for demographic, clinical, health behavior, and disability factors.
  
  
  RESULTS
  Of 9,496 participants meeting the inclusion criteria, 502 (5.3%) were deceased. Most participants reported having ≤3 comorbid conditions (70.9% survivors, 76.9% decedents). In individual regression models, vascular, visual, and mental comorbidities were associated with increased mortality risk after adjustment for factors associated with survival. When combined into a single model, vascular (hazard ratio 1.269; 1.041-1.547), visual (1.490; 1.199-1.852), and mental comorbidities (excluding anxiety, 1.239; 1.024-1.499) remained independently associated with an increased risk of mortality.
  
  
  CONCLUSIONS
  Presence of comorbidities was independently associated with an increased risk of mortality as compared to absence of comorbidities after adjusting for factors associated with survival. Specifically, vascular, visual, and mental comorbidities increased the risk of mortality. This highlights the need for clinicians to attend to these comorbidities, which can be modified by treatments or other interventions, and potentially reduce the risk of mortality in persons with MS who have these conditions.
authors.affiliation: Division of Biostatistics (AS, GW), Washington University in St. Louis, MO; Division of Neurology (TT), Dignity Health, St. Joseph's Hospital and Medical Center, Phoenix, AZ; Department of Neurology and Neurological Institute (RJF), Cleveland Clinic, OH; Department of Biostatistics (GC), University of Alabama at Birmingham; and Departments of Internal Medicine and Community Health Sciences (RAM), University of Manitoba, Winnipeg, Canada.
authors.forename: Amber
authors.initials: A
authors.lastname: Salter
authors.affiliation: Division of Biostatistics (AS, GW), Washington University in St. Louis, MO; Division of Neurology (TT), Dignity Health, St. Joseph's Hospital and Medical Center, Phoenix, AZ; Department of Neurology and Neurological Institute (RJF), Cleveland Clinic, OH; Department of Biostatistics (GC), University of Alabama at Birmingham; and Departments of Internal Medicine and Community Health Sciences (RAM), University of Manitoba, Winnipeg, Canada.
authors.forename: Tuula
authors.initials: T
authors.lastname: Tyry
authors.affiliation: Division of Biostatistics (AS, GW), Washington University in St. Louis, MO; Division of Neurology (TT), Dignity Health, St. Joseph's Hospital and Medical Center, Phoenix, AZ; Department of Neurology and Neurological Institute (RJF), Cleveland Clinic, OH; Department of Biostatistics (GC), University of Alabama at Birmingham; and Departments of Internal Medicine and Community Health Sciences (RAM), University of Manitoba, Winnipeg, Canada.
authors.forename: Guoqiao
authors.initials: G
authors.lastname: Wang
authors.affiliation: Division of Biostatistics (AS, GW), Washington University in St. Louis, MO; Division of Neurology (TT), Dignity Health, St. Joseph's Hospital and Medical Center, Phoenix, AZ; Department of Neurology and Neurological Institute (RJF), Cleveland Clinic, OH; Department of Biostatistics (GC), University of Alabama at Birmingham; and Departments of Internal Medicine and Community Health Sciences (RAM), University of Manitoba, Winnipeg, Canada.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Fox
authors.affiliation: Division of Biostatistics (AS, GW), Washington University in St. Louis, MO; Division of Neurology (TT), Dignity Health, St. Joseph's Hospital and Medical Center, Phoenix, AZ; Department of Neurology and Neurological Institute (RJF), Cleveland Clinic, OH; Department of Biostatistics (GC), University of Alabama at Birmingham; and Departments of Internal Medicine and Community Health Sciences (RAM), University of Manitoba, Winnipeg, Canada.
authors.forename: Gary
authors.initials: G
authors.lastname: Cutter
authors.affiliation: Division of Biostatistics (AS, GW), Washington University in St. Louis, MO; Division of Neurology (TT), Dignity Health, St. Joseph's Hospital and Medical Center, Phoenix, AZ; Department of Neurology and Neurological Institute (RJF), Cleveland Clinic, OH; Department of Biostatistics (GC), University of Alabama at Birmingham; and Departments of Internal Medicine and Community Health Sciences (RAM), University of Manitoba, Winnipeg, Canada.
authors.forename: Ruth Ann
authors.initials: RA
authors.lastname: Marrie