The implications of suboptimal year-1 outcomes with disease-modifying therapy in employees with multiple sclerosis

Multiple sclerosis (MS) poses a substantial employer burden in medically related absenteeism and disability costs due to the chronic and debilitating nature of the disease. Although previous studies have evaluated relapse, nonadherence, discontinuation, and switching individually, little is known about their overall collective prevalence and implications in employees with MS treated with disease-modifying therapies (DMTs). This study evaluated the proportion of employees with MS with suboptimal DMT year-1 outcomes and to quantify the clinical and economic burden of suboptimal year-1 outcomes from a US employer perspective.

Employees with MS were selected from the Workpartners database. Eligibility criteria were: ≥2 MS diagnosis claims (ICD-9-CM 340.xx/ICD-10-CM G35) from January 1, 2010-March 31, 2019, ≥1 once-/twice-daily oral or self-injectable DMT claim (first claim = index), continuous eligibility 6-months pre-/1-year post-index, no baseline DMT, and age 18-64 years. Suboptimal year-1 outcomes included: non-adherence (proportion of days covered <80%), discontinuation (gap >60 days), switch, or relapse (MS-related hospitalization, emergency room visit, or outpatient visit with corticosteroid). A two-part logistic-generalized linear model evaluated costs.

Of 488 eligible patients, half (n = 247; 50.6%) had suboptimal year-1 outcomes (39.5% non-adherence, 9.8% discontinuation, 10.9% switching, 20.7% relapse; not mutually exclusive). Employees with suboptimal year-1 outcomes had higher all-cause medical ($12,730 vs. $6,428; p < 0.0001), MS-related medical ($5,444 vs. $2,652; p < 0.0001), non-DMT pharmacy ($2,920 vs. $2,169; p = 0.0199), sick leave ($1247 vs. $908; p = 0.0274), and short-term disability ($934 vs. $146; p = 0.0001) costs. Long-term disability ($751 vs. $0; p = 0.1250) and Workers' Compensation ($56 vs. $24; p = 0.1276) did not significantly differ.

Administrative claims lack clinical information. Results may not be generalizable to other patients or care settings.

Half of the employees with MS in this sample had suboptimal year-1 outcomes (i.e. non-adherence, discontinuation, switching, or relapse). These suboptimal year-1 outcomes were associated with greater medical, sick leave, and short-term disability costs.