Greater DMT Adherence Linked With Superior Outcomes Among Veterans With MS

Veterans with multiple sclerosis (MS) who adhered to their disease-modifying therapies (DMTs) experienced less decline in MS-related cognition, disease severity, and disability compared with those who were nonadherent or adhered poorly to their DMTs, according to findings published in Journal of Central Nervous System Disease.

Study results were consistent even after adjusting for age, gender, MS duration, and type, the authors said. Although “maintaining adherence to therapies long term for chronic medical conditions…is challenging both for the provider and the patient,” in most patients with MS, doing so can prevent relapses and delay disease progression, they explained.

Adherence rates among those with MS are estimated to be between 41% and 88%, while rates vary for different injectable DMTs.

Military veterans constitute approximately 7% of the United States population, and they receive medical care irrespective of socioeconomic status. In the current study, the researchers sought to compare functional outcomes between veterans with MS who were adherent to their DMTs with those who were nonadherent.

“To the best of our knowledge, this issue has not been previously studied due largely to the length and completeness of observation needed,” the authors noted.

A total of 279 veterans with diagnosed MS were included in the retrospective, observational study. All patients were followed-up with every 4, 8, and 12 months at the Oklahoma City Veterans Affairs Medical Center between January 2000 and December 2019. Any individual with an incomplete electronic medical record was excluded from the analysis.

Nonadherent individuals were defined as those who initially took but then stopped taking the prescribed DMTs or individuals who refused to take the prescribed DMTs. In addition, veterans with good adherence “took the prescribed DMT on a regular basis as prescribed. Veterans were categorized as demonstrating poor adherence if they took the prescribed DMT infrequently, missing 2 or more doses in a 4-week period on a regular basis,” the authors wrote.

The majority of patients included were men (80%), while 41% of patients had relapsing-remitting MS and 43% had progressive MS.

Analyses revealed:

• 148 (53%) veterans with MS were nonadherent to any DMT medication(s)
• Of the 131 (47%) veterans who were taking medications, 118 (42%) had good and 13 (5%) had poor adherence
• Mean (SD) age at MS onset was 36.6 (11.2) years, and the mean duration of MS for the sample was 24 (13.5) years
• Mean initial Expanded Disability Status Score (EDSS) and total Functional Independence Measure (TFIM) scores were 4.09 (2.9) and 104 (25.7) for the study sample, respectively
• Change in Mini-Mental Status Examination, TFIM scores, and time to sustained EDSS score of 6 significantly favored the good- compared to the nonadherence group (P < .01)

Among the nonadherent group, the main reasons for not taking DMT(s) included a perceived lack of beneficial effect on the disease, medication adverse events (injection site reactions and depression), and the need to take the DMT over a long period of time.

“Though no significant differences were noted in the functional outcome measures between good- and poor-adherence groups, which could reflect on the small sample size of the poor-adherence group…the change scores still favored the good-adherence group,” the authors wrote.

As the sample comprised largely non-Hispanic White men, the findings may not be generalizable to the wider MS population, marking a limitation to the study. The small sizes of the 3 adherence groups also reduces power to detect association, potentially leading to biased results.

“Despite these limitations, the retrospective analysis…provides a relevant rich and robust dataset to better understand how adherence to DMT affects level of cognition and disability in the veterans with MS,” the researchers concluded.

Reference

Rabadi MH, Just K, and Xu C.The impact of adherence to disease-modifying therapies on functional outcomes in veterans with multiple sclerosis.J Cent Nerv Syst Dis. Published online July 6, 2021. doi:10.1177/11795735211028769