Objective:

To evaluate the real-world clinical and economic burden in treated versus untreated people with relapsing-remitting multiple sclerosis (pwRRMS) in the United States (US).

Background:

Disease-modifying therapies (DMTs) are central to managing RRMS and improving outcomes. However, despite the availability of multiple treatment options, many pwRRMS remain untreated, and real-world evidence comparing treated versus untreated in pwRRMS is limited.

Design/Methods:

This retrospective cohort study was conducted using a US-based claims database (07/01/2020–06/30/2023). PwRRMS were identified using a validated algorithm and segregated into treated (received DMTs during 1-year baseline) and untreated (no DMTs during 1-year baseline) cohorts. Demographics, comorbidities, healthcare resource utilization (HCRU), and healthcare costs (adjusted to 2023 US-dollars) were analyzed.

Results:

The final cohorts included 8,763 treated (mean±standard deviation [SD]: 48.9±10.7 years; 73.6% female) and 5,473 untreated (53.5±13.9 years; 78.3% female) pwRRMS. The mean±SD Charlson Comorbidity Index score (0.5±1.1 vs. 1.0±1.7) and infections (50.6% vs. 54.3%) were significantly lower in the treated versus untreated cohorts (P<0.001). The top three MS‑related comorbidities in the treated versus untreated cohorts were malaise/fatigue (23.9% vs. 28.2%), depression (16.7% vs. 19.9%), and burning/numbness/tingling (13.7% vs. 20.5%; all P<0.001). At follow-up, the treated cohort had a significantly lower rate of hospitalizations (4.3% vs. 9.7%) and emergency department (ED) visits (16.2% vs. 24.1%; all P<0.001), and mean number of physician visits (10.9 vs. 12.7; P=0.002) versus the untreated cohort. The mean all-cause costs of hospitalizations ($1,621 vs. $3,473) and ED visits ($365 vs. $617) were lower in the treated versus untreated cohorts (P<0.001). The most common risk factors for not receiving DMT were stroke (odds-ratio: 1.85 [95% CI: 1.5–2.2]) and fibromyalgia/myositis (1.9 [1.6–2.1]).

Conclusions:

The untreated cohort had a higher comorbidity burden and medical costs, and greater HCRU, versus the treated cohort, highlighting the potential clinical and economic benefits of treatment whilst underscoring the continued unmet need in the untreated pwRRMS.