Comorbidities as predictors of all-cause emergency department utilization among veterans with multiple sclerosis.

Background: While comorbidities have been associated with all-cause hospitalizations among persons with multiple sclerosis (MS), there has been no examination of their role in all-cause emergency department (ED) utilization. As such, this study aimed to determine if the presence of comorbidities increases the odds of ED usage in a national sample of Veterans with MS.

Methods: Data were extracted retrospectively from the Veterans Affairs (VA) MS Center of Excellence Data Repository, an electronic health record-based dataset. Veterans who had at least one outpatient visit in 2013, were alive in 2015, and were initially prescribed a disease modifying therapy were included in the dataset (n = 3,742). Current Procedural Terminology codes were used to determine if participants had at least one ED visit during a 24-month time frame beginning 1/1/2013. Comorbidities were identified using ICD-9 codes present before 2013. Separate logistic regressions were conducted for the overall number of comorbidities and categorized comorbidities, adjusting for age, race, and sex.

Results: Nearly 32% (n = 1,191) had at least one ED visit, with those Veterans having an average of 6.67 (SD=3.32) comorbidities. After adjusting for demographics, the number of comorbidities was a significant predictor of ED usage (aOR=1.20; 95% CI: 1.17, 1.23, p<.001). Several comorbidities emerged as independent contributors.

Conclusions: All-cause ED utilization is prevalent in MS, with usage increasing in the presence of other chronic conditions. These findings underscore the need to view long-term MS care through the lens of chronic disease management.