Presentation (CTI)

OBJECTIVES: To describe real-world pre-index diagnosis specialist visits and diagnosis code patterns in newly diagnosed Multiple Sclerosis patients.
METHODS: A retrospective analysis of administrative U.S. claims data identified Multiple Sclerosis patients with claims activity between 2017 and 2025. Patients were stratified into quintiles using age at MS index date. The MS index date was defined as the date of first observed claim with ICD-10 code G35. Patients were required to have at least 3 claims with G35, separated by at least 12 months. To ensure a new diagnosis of MS or a new relapse, patients were required to have at least 36 months of claims activity before MS index date. The prevalence of diagnoses and specialist visits 36 months before MS index date were calculated within each quintile.
RESULTS: The final study population included 50,669 Multiple Sclerosis patients (79% Female). The mean age at MS index was 30.39 years (SD 6.26) in the youngest quintile and 74 years (SD 5.28) in the eldest. Of females in the youngest quintile (n=8,494), 26% had a pregnancy related ICD-10 code. In the youngest quintile (n=10,209), 50% had anxiety disorders, 34% had depression, and 34% had paresthesia of skin (vs 9% in eldest). The prevalence of acute vaginitis decreases, from 19% in the youngest quintile, as age at MS index increases (3^rd quintile - 6%, eldest - 3%). The prevalence of urinary tract infections increases from 23% in the youngest quintile to 34% in the eldest. Visits to Ophthalmology and Cardiovascular Disease specialists were most common the eldest quintile (43% and 41% respectively) while visits to Neurologists were more common in younger quintiles.
CONCLUSIONS: In a large real-world population of MS patients, the diagnosis code profile pre-index date varied widely across age at MS diagnosis or flare up. These descriptive findings provide context for future longitudinal research.