The association of timing of disease-modifying drug initiation and relapse in patients with multiple sclerosis using electronic health records.

ABSTRACT

OBJECTIVE: A large, US de-identified electronic health record (EHR) database (Optum-Humedica de-identified Electronic Health Record dataset) was used to evaluate whether earlier disease-modifying drug (DMD) treatment initiation was associated with improved outcomes in multiple sclerosis (MS). METHODS: Newly diagnosed patients from 1 January 2008 to 30 August 2014 (International Classification of Diseases, Ninth Revision, Clinical Modification code 340.xx; first MS diagnosis = index date) with healthcare activity 1 year pre- and 2 years post-index, and who initiated DMD treatment during the 2 year follow-up period, were included. Patients were categorized as Early or Late Initiators (initiated DMD treatment ≤90 or >90 days following index, respectively). Relapse was determined by the presence of an MS-related hospitalization or an outpatient encounter with MS diagnosis and corticosteroid prescription within 7 days. RESULTS: A total of 4732 patients met the inclusion criteria 2042 (43.2%) were Early Initiators and 2690 (56.8%) were Late Initiators. Similar baseline mean age (46.9 years for both cohorts) and Charlson Comorbidity Index scores (Early Initiators 0.3, Late Initiators 0.32) were observed. Average time to treatment was 20.9 ± 27.6 days for Early Initiators and 346.3 ± 181.1 days for Late Initiators. A significantly higher proportion of Late Initiators (n = 609; 22.6%) had a relapse during the 2 years following MS diagnosis compared with Early Initiators (n = 403; 19.7%; p = .0158). After controlling for covariates using multivariable logistic regression, late initiation of DMD treatment was associated with greater likelihood of relapse compared with early initiation (odds ratio 1.189; 95% CI 1.031-1.371; p = .0172). CONCLUSIONS: Later initiation of DMD treatment (i.e. >90 days after MS diagnosis) in patients with MS was associated with a greater likelihood of relapse compared with earlier initiation. Early initiation of DMD treatment following a diagnosis of MS may have an effect on long-term outcomes.