Impact of Adherence with Disease-Modifying Therapies on All-Cause Mortality Rates Among Veterans with Multiple Sclerosis

BACKGROUND: Adherence to disease-modifying therapies (DMTs) is essential for reducing multiple sclerosis (MS)-related relapses and disability. However, no known data exist regarding rates of adherence to DMTs and their impact on mortality. The present study aimed to determine the effect of adherence to DMTs on all-cause mortality in patients with MS in a real-world setting. MATERIAL/METHODS: We reviewed electronic records of 279 patients with MS and followed them longitudinally in our MS clinic between Januray1, 2000 and December 31, 2019. The inclusion criteria were complete electronic records along with documentation of initial and final functional outcome measures, including mortality. The exclusion criteria were incomplete electronic records and lack of documentation of initial and final functional outcome measures. RESULTS: Of 279 patients with MS, 148 (53.0%) were non-adherent to any DMT medication(s). Of the 131 (47.0%) MS patients who were adherent, 13 (4.7%) had poor adherence and 118 (42.3%) had good adherence. More patients in the good-adherence group survived (94.9%) compared to the non-adherence group (66.9%, P<0.001). The odds of being alive were 12 times higher among those who adhered to their DMT compared to those who did not. CONCLUSIONS: This study indicates that veterans who adhere to their DMTs are 12 times more likely to be alive than those who are non-adherent, even after adjusting for variables known to affect S-related mortality such as age at entry, MS type, MS duration, body mass index, and diabetes.