The Impact of Adherence to Disease-Modifying Therapies on Functional Outcomes in Veterans with Multiple Sclerosis

Background: Patients who adhere to their DMTs have lower rate of MS-related relapses and disability. Objective: We sought to determine the adherence rate to disease-modifying therapies (DMTs) and its impact on functional outcome(s) in veterans with multiple sclerosis (MS). Method: We reviewed the electronic records of 279 veterans with MS who were periodically followed in our MS clinic. We compared 3 groups of patients, defined according to their adherence to DMTs (non-adherent; poorly adherent; adherent) on their effect on disability progression and time to sustained EDSS score of 6. Results: There were 148 (53%) veterans with MS who were non-adherent to any DMT medication(s) while of the 131 (47%) veterans who were taking medications, 118 (42%) had a good- and 13 (5%) had poor-adherence. The mean age at MS onset was 36.6 (± 11.2) and mean duration of MS for the sample was 24 ± 13.5 years. The mean initial EDSS and TFIM scores were 4.09 ± 2.9 SD and 104 ± 25.7 for the study sample. The change in MMSE, TFIM scores, and time to sustained EDSS score of 6 significantly favored the good- compared to the non-adherence group ( P < .01). Conclusion: This study suggests that veterans with MS who adhered to their DMTs had less decline in their MS-related cognition, disease severity and disability compared to non- and poorly-adherent groups even after adjusting for age, gender, MS duration, and type. Time to EDSS score of 6 was significantly prolonged in the good-adherence group.