Presentation (CTI)

OBJECTIVES: Selecting the initial treatment strategy is critical in managing multiple sclerosis (MS). Initiation of moderate-efficacy disease-modifying therapies (meDMTs) is the most common practice for MS patients, while high-efficacy disease-modifying therapies (heDMTs) are increasingly considered due to greater availability and better effectiveness. This study applied a causal forest model to identify important features for evaluating heterogeneous treatment effects (HTEs) of DMTs for MS patients.
METHODS: We used 2014-2024 Merative MarketScan Commercial healthcare claims data to identify MS patients. The study selected patients who initiated heDMTs or meDMTs with a 12-month washout period. One-to-one propensity score matching was used to balance baseline characteristics between patients in heDMTs and meDMTs. The outcome of interest was any MS relapse within a 12-month follow-up after the index date. We developed two causal forest models to detect important features for evaluating HTE. The first model used the “grf” package in R and modeled the absolute risk of relapse. The other model used the “rrcf” package and modeled the relative risk of relapse. Hyperparameters of the first model were tuned using cross-validation through functions within the “grf” package. The second model used the default settings of hyperparameters in the “rrcf” package.
RESULTS: After matching, we included 2,814 matched MS patients. The proportion of MS relapse for the heDMT and meDMT cohorts was 11.23% and 10.87%, respectively. The top five important features identified by the absolute risk model were obesity status, brainstem symptoms, anticonvulsant medication use, hypothyroidism, and bladder/bowel symptoms. The top five features identified by the relative risk model were other neurological disorders, full-time employment, brainstem symptoms, obesity status, and a high number of MS-related outpatient visits.
CONCLUSIONS: Comorbidities and MS-related clinical features may influence the comparative effectiveness of treatment between heDMTs and meDMTs. Further research is needed to evaluate the role of these factors in HTE of DMTs.