Phenome-wide examination of comorbidity burden and multiple sclerosis disease severity

We assessed the comorbidity burden associated with multiple sclerosis (MS) severity by performing a phenome-wide association study (PheWAS).We conducted a PheWAS in 2 independent cohorts: a discovery (Boston, United States; 1993-2014) and extension cohort (British Columbia, Canada; 1991-2008). We included adults with MS, ≥1 Expanded Disability Status Scale (EDSS) score, and ≥1 International Classification of Diseases (ICD) code other than MS. We...