Emergency department use before multiple sclerosis: Presenting complaints and discharge diagnoses.

BACKGROUND: Emergency department (ED) visits represent a substantial component of healthcare use. Although increased utilization has been reported before multiple sclerosis (MS) recognition, ED use and its clinical context remain poorly characterized. METHODS: In this population-based matched cohort study, we used linked administrative health data from British Columbia, Canada. Persons with multiple sclerosis (PwMS) were identified using a validated case definition and matched to individuals without MS by age, sex and postal code. ED encounters in the 5 years preceding the index date (first demyelinating disease claim) were examined. Annual ED visit rates were compared using adjusted negative binomial models; discharge diagnoses were assessed using adjusted logistic regression. RESULTS: The cohort included 2383 PwMS and 11,896 matched individuals (mean age = 44.1 years; 69.2% female). ED visit rates were higher among PwMS across all five pre-index years, rising from an adjusted rate ratio (aRR) of 1.38 (95% confidence interval (CI) = 1.07-1.77) at 5 years pre-index to 3.40 (95% CI = 3.07-3.76) in the year immediately pre-index. Excess visits were observed for gastrointestinal, genitourinary, musculoskeletal, respiratory, mental health, and ill-defined conditions. PwMS had higher odds of a non-specific discharge diagnosis (adjusted odds ratio (aOR) = 1.36; 95% CI = 1.22-1.53). CONCLUSIONS: ED utilization was consistently elevated in the 5 years before MS recognition (index date), predominantly involving non-neurologic and non-specific presentations.