To estimate obesity prevalence and related demographics and comorbidities among adults with multiple sclerosis (MS) using a large multi-health-system electronic health record (EHR) network.

Obesity has been linked to higher risks of developing MS, greater inflammatory activity, and faster disability accrual. Contemporary, system-level estimates of obesity burden among people with MS (PwMS) using real-world data can inform clinical management and population health planning.

We conducted a descriptive cross-sectional study using Epic Cosmos, a de-identified, real-world dataset derived from EHRs across multiple healthcare institutions in the US, covering >300 million patients. We queried Epic Cosmos to identify “base patients” (≥2 encounters in any two-year span) aged ≥18 years with an MS diagnosis (ICD-10: G35.*) between 9/24/2005 and 9/23/2025. We then filtered the cohort to those with body mass index (BMI) ≥30 documented within the last 3 years and further filtered to those with an ICD-10 obesity diagnosis (E66.*) to estimate obesity prevalence in MS. Demographics and major comorbidities were summarized.

We identified 719,787 adult PwMS (mean age 56.7±15.2 years; 74.4% female; 79.6% White, 14.7% Black). Of these, 272,750 (37.9%) had BMI ≥30 in the prior 3 years, and 180,085 (25.0%) had both BMI ≥30 and an ICD-10 diagnosis of obesity. Our preliminary results showed that in the obesity-defined MS subset (n=180,085), the mean age was 55.0±13.9 years; 80.9% were female, and 73.9% were White and 21.8% Black. The most common comorbidity in the obesity cohort was hypertension (57.5%). Other relevant comorbidities included hyperlipidemia (52.7%), obstructive sleep apnea (25.4%), type-2 diabetes (24.1%), and heart disease (10.1%).

Approximately one in four adults with MS carried both anthropometric (BMI ≥30) and diagnostic (ICD-10 E66.*) evidence of obesity, and nearly two in five had BMI-defined obesity. Obesity in MS co-occurred with substantial cardiometabolic and sleep-related comorbidity, underscoring opportunities for integrated risk-factor management alongside disease-modifying therapy.