To assess the relationship between comorbid autoimmune diseases (ADs) and psychiatric disorders among patients with MS, and to elucidate possible environmental factors or health disparities within this relationship.

Multiple Sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) that has a high prevalence of autoimmune and psychiatric comorbidities. Previous studies have not addressed how these comorbidities in MS relate to each other.

A retrospective case-control study was conducted using patient records from Hawaii with a diagnosis of MS from January 2000 to June 2022. Sociodemographic variables, clinical characteristics, and comorbidities were collected. Variables between the AD status groups were compared using the Wilcoxon rank sum test for continuous variables and Pearson’s Chi-squared test or Fisher’s exact test for categorical variables. A p-value less than 0.05 was considered statistically significant.

Of the 105 patients with MS analyzed, 28% (n=30) had comorbid ADs. The proportion of the type Primary Progressive MS among them was higher, compared to patients without ADs (30.8% vs. 11.1%; p = 0.030). They were also found to have a significantly higher prevalence of depression (50% vs. 25%; p = 0.015) and, although not significant, anxiety (30% vs. 21%; p=0.35), compared to the group without ADs. Comorbid ADs in MS did not seem to be associated with sociodemographic factors, but did appear to be associated with a significantly higher prevalence of health disparities, such as asthma (26.7% vs. 10.7%; p=0.067) and coronary artery diseases (13.3% vs. 2.7%; p=0.054).

Our findings suggest that comorbid ADs are associated with increased risks of depression and other debilitating health disparities among patients with MS. This result can influence treatment options and inter-specialty care management to improve the outcomes in MS patients with comorbid ADs.