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Dive into the research topics where Ralph I. Horwitz is active.

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Featured researches published by Ralph I. Horwitz.


Neurology | 2010

Vascular comorbidity is associated with more rapid disability progression in multiple sclerosis

Ruth-Ann Marrie; Richard A. Rudick; Ralph I. Horwitz; Gary Cutter; Tuula Tyry; Denise I. Campagnolo; Timothy Vollmer

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.


Neurology | 2009

Comorbidity delays diagnosis and increases disability at diagnosis in MS

Ruth-Ann Marrie; Ralph I. Horwitz; Gary Cutter; Tuula Tyry; Denise Campagnolo; Timothy Vollmer

Background: Comorbidity is common in the general population and is associated with adverse health outcomes. In multiple sclerosis (MS), it is unknown whether preexisting comorbidity affects the delay between initial symptom onset and diagnosis (“diagnostic delay”) or the severity of disability at MS diagnosis. Objectives: Using the North American Research Committee on Multiple Sclerosis Registry, we assessed the association between comorbidity and both the diagnostic delay and severity of disability at diagnosis. In 2006, we queried participants regarding physical and mental comorbidities, including date of diagnosis, smoking status, current height, and past and present weight. Using multivariate Cox regression, we compared the diagnostic delay between participants with and without comorbidity at diagnosis. We classified participants enrolled within 2 years of diagnosis (n = 2,375) as having mild, moderate, or severe disability using Patient Determined Disease Steps, and assessed the association of disability with comorbidity using polytomous logistic regression. Results: The study included 8,983 participants. After multivariable adjustment for demographic and clinical characteristics, the diagnostic delay increased if obesity, smoking, or physical or mental comorbidities were present. Among participants enrolled within 2 years of diagnosis, the adjusted odds of moderate as compared to mild disability at diagnosis increased in participants with vascular comorbidity (odds ratio [OR] 1.51, 95% CI 1.12–2.05) or obesity (OR 1.38, 95% CI 1.02–1.87). The odds of severe as compared with mild disability increased with musculoskeletal (OR 1.81, 95% CI 1.25–2.63) or mental (OR 1.62, 95% CI 1.23–2.14) comorbidity. Conclusions: Both diagnostic delay and disability at diagnosis are influenced by comorbidity. The mechanisms underlying these associations deserve further investigation.


Multiple Sclerosis Journal | 2008

Comorbidity, socioeconomic status and multiple sclerosis

Ruth-Ann Marrie; Ralph I. Horwitz; Gary Cutter; Tuula Tyry; Denise I. Campagnolo; Timothy Vollmer

Objective Multiple sclerosis (MS) is associated with substantial morbidity. The impact of comorbidity on MS is unknown, but comorbidity may explain some of the unpredictable progression. Comorbidity is common in the general population, and is associated with adverse health outcomes. To begin understanding the impact of comorbidity on MS, we need to know the breadth, type, and frequencies of comorbidities among MS patients. Using the North American Research Committee on Multiple Sclerosis (NARCOMS) Registry, we aimed to describe comorbidities and their demographic predictors in MS. Methods In October 2006, we queried NARCOMS participants regarding physical comorbidities. Of 16,141 participants meeting the inclusion criteria, 8983 (55.7%) responded. Results Comorbidity was relatively common; if we considered conditions which are very likely to be accurately self-reported, then 3280 (36.7%) reported at least one physical comorbidity. The most frequently reported comorbidities were hypercholesterolemia (37%), hypertension (30%), and arthritis (16%). Associated with the risk of comorbidity were being male [females vs. males, odds ratio (OR) 0.77; 0.69–0.87]; age (age >60 years vs. age ≤44 years, OR 5.91; 4.95–7.06); race (African Americans vs. Whites, OR 1.46; 1.06–2.03); and socioeconomic status (Income <


Multiple Sclerosis Journal | 2009

The burden of mental comorbidity in multiple sclerosis: frequent, underdiagnosed, and undertreated

Ruth-Ann Marrie; Ralph I. Horwitz; Gary Cutter; Tuula Tyry; Denise Campagnolo; Timothy Vollmer

15,000 vs. Income >


Lancet Neurology | 2010

Emerging effects of comorbidities on multiple sclerosis

Ruth Ann Marrie; Ralph I. Horwitz

100,000, OR 1.37; 1.10–1.70). Conclusions Comorbidity is common in MS and similarly associated with socioeconomic status.


Multiple Sclerosis Journal | 2009

High frequency of adverse health behaviors in multiple sclerosis

Ruth-Ann Marrie; Ralph I. Horwitz; Gary Cutter; Tuula Tyry; Denise Campagnolo; Timothy Vollmer

Background Mental comorbidity is common in multiple sclerosis (MS), but some studies suggest that mental comorbidity may be underrecognized and undertreated. Objective Using the North American Research Committee on MS Registry, we assessed the frequency of mental comorbidities in MS and sociodemographic characteristics associated with diagnosis and treatment of depression. Methods We queried participants regarding depression, anxiety, bipolar disorder, and schizophrenia. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale (CESD); a score ≥21 indicated probable major depression. Results Mental comorbidity affected 4264 (48%) responders; depression most frequently (4012, 46%). Among participants not reporting mental comorbidity, 751 (16.2%) had CESD scores ≥21 suggesting undiagnosed depression. Lower socioeconomic status was associated with increased odds of depression (Income


American Journal of Public Health | 2009

Racial, ethnic, and socioeconomic differences in the incidence of obesity related to childbirth.

Esa M. Davis; Stephen J. Zyzanski; Christine M. Olson; Kurt C. Stange; Ralph I. Horwitz

15,000–30,000 vs >


Acta Neurologica Scandinavica | 2011

Association between comorbidity and clinical characteristics of MS

Ruth Ann Marrie; Ralph I. Horwitz; Gary Cutter; Tuula Tyry; Timothy Vollmer

100,000 OR 1.34; 1.11–1.62), undiagnosed depression (Income


Acta Neurologica Scandinavica | 2012

Cumulative impact of comorbidity on quality of life in MS.

Ruth Ann Marrie; Ralph I. Horwitz; Gary Cutter; Tuula Tyry

15,000–30,000 vs >


Neuroepidemiology | 2011

Smokers with Multiple Sclerosis Are More Likely to Report Comorbid Autoimmune Diseases

Ruth Ann Marrie; Ralph I. Horwitz; Gary Cutter; Tuula Tyry; Timothy Vollmer

100,000 OR 1.52; 1.08–2.13), and untreated depression (<high school vs postgraduate degree OR 3.13; 1.65–5.99). Conclusions Mental comorbidity remains underdiagnosed and undertreated in MS. Patients of lower socioeconomic status bear a disproportionate share of the burden of depression.

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Gary Cutter

University of Alabama at Birmingham

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Tuula Tyry

St. Joseph's Hospital and Medical Center

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Timothy Vollmer

University of Colorado Boulder

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Denise Campagnolo

Barrow Neurological Institute

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Esa M. Davis

Case Western Reserve University

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Kurt C. Stange

University Hospitals of Cleveland

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Stephen J. Zyzanski

University of Colorado Denver

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