Medication adherence linked to greater survival for US veterans prescribed DMTs
by Marisa Wexler, MS |
The likelihood of survival is about 7.5 times higher for people with multiple sclerosis (MS) who take their disease-modifying treatments as directed compared with those who do not, an analysis of data from U.S. veterans shows.
The study, “Impact of Adherence with Disease-Modifying Therapies on All-Cause Mortality Rates Among Veterans with Multiple Sclerosis,” was published in Medical Science Monitor.
MS is not itself a fatal disease, but it can increase the risk of life-threatening complications like pneumonia. The average life expectancy is about 5–10 years shorter for someone diagnosed with MS than the general population.
Disease-modifying therapies, or DMTs, are medicines that have been proven to alter the course of MS — reducing inflammatory damage in the brain and slowing the progression of disabling symptoms. There are more than a dozen DMTs approved for relapsing types of MS in the U.S.
For any medication to be maximally effective, the patient needs to take the medication on time and as often as required. Patients who take their medications as directed are said to be “adherent” to their prescription.
A trio of scientists in Oklahoma analyzed data from 279 people with MS who were treated at the Oklahoma City Veterans Affairs Medical Center from 2000 to 2019.
Based on adherence data, patients were divided into three groups: 118 (42.3%) of the patients were classified as having good adherence, meaning they took their medications as directed. Another 13 (4.7%) had poor adherence, meaning they took their DMTs but not as frequently as recommended (about 80%–90% of treatment days).
The remaining 148 (53%) of patients were non-adherent, meaning they elected not to take their medicines for reasons such as side effects or a perceived lack of efficacy. These patients took their medications on fewer than 80% of treatment days, according to prescription refill information on electronic medical records.
Over the 20-year study period, 56 (20.1%) of the patients died. Compared with those who survived, these patients showed some expected differences — they were more than a decade older on average, with longer disease duration, and more advanced disability.
Also, the majority of patients who died (89.3%) were not receiving or had never received a DMT, compared with 44.4% of those who were alive.
In the good adherence group, patients lived for a median of 52 years after diagnose, compared with 35 years for those in the non-adherence group, and more of them were alive at the study’s end (94.9% vs. 66.9%).
The median survival time for the poor-adherence group was 62 years, and one of the 13 patients died during the study; the researchers noted that this group was too small to conduct reliable analyses.
In unadjusted statistical analyses — that is, without taking into account factors like starting age and disability scores — the chances of being alive were 12 times higher for patients who had poor or good adherence compared with those who were non-adherent.
After adjusting for factors such as age at study entry, disease duration, and MS type, the risk of death was 7.5 times higher in the non-adherence group compared to the good adherence group. Those with poor adherence were not included in this analysis due to the low number.
A noted limitation of this study, the researchers said, is that the vast majority of patients were non-Hispanic white men, so it’s not clear how much these results can be generalized to the overall MS population. The small size of the study and its real-world setting were also noted as limitations.
“This study indicates that veterans who adhere to their DMTs are 12 times more likely to be alive than non-adherent groups,” the researchers wrote, adding that they now hope to include a pharmacist in their MS team to help increase adherence to DMTs among MS patients.
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