Early preventive heart treatment extends survival in DMD: Study
But just 1 in 4 US patients prescribed prophylactic medication, per data
Preventive treatment with standard heart medications — when given before the onset of cardiac troubles — extends survival among males with Duchenne muscular dystrophy (DMD), according to data from the U.S.-based Muscular Dystrophy Surveillance, Tracking and Research Network, known as MD STARnet.
However, despite finding such benefits with prophylactic, or preventive, heart treatments, a team of U.S. researchers also determined that just 1 in 4 DMD patients in the country was prescribed such medication.
“Our study shows an association between prophylactic cardiac treatment and prolonged survival among individuals with DMD in a population-based cohort,” the team wrote.
But key, the team said, was starting such treatment early.
“The findings support delay of [heart muscle disease] as a significant contributor to prolonged survival and provide additional strong support for current recommendations to initiate prophylactic cardiac medication before [heart problems],” the researchers wrote.
Their study, titled “Prophylactic Use of Cardiac Medications and Survival in Duchenne Muscular Dystrophy,” was published in the journal Muscle & Nerve.
Investigating whether early preventive treatment prolongs survival
DMD is a genetic disorder marked by virtually no dystrophin, a protein that helps protect muscles from damage. Over time, this deficiency leads to progressive damage to skeletal muscles, or those responsible for movement, as well as heart muscles.
Common heart problems in DMD include disease of the heart muscle, known as cardiomyopathy, and abnormal heartbeats, or cardiac arrhythmias. People with DMD, which primarily affects males, also experience left ventricular dysfunction, or LVD, characterized by the inability of the heart’s left ventricle to pump blood through the body.
Current recommendations for treating heart problems in DMD include starting heart medicines — specifically ones that lower blood pressure — by age 10. This is intended to delay the onset or slow the progression of cardiomyopathy.
In earlier research using MD STARnet data, a team at the University of Iowa and other institutions reported that six times more patients who received preventive cardiac medication survived without LVD to age 27 relative to untreated patients (52.5% vs. 8.5%).
Given these findings, starting heart medications early is expected to prolong overall survival. However, the researchers noted that this effect has not been systematically studied.
To address this, the team collected data on 325 DMD males enrolled in MD STARnet. Among them, 90 (27.7%) began preventive heart medication before the onset of LVD, and 157 (60.9%) received corticosteroids.
The vast majority of those given heart treatments (86.7%) were prescribed ACE, or angiotensin-converting enzyme, inhibitors. About 7% of patients received ARBs, fully known as angiotensin II receptor blockers, or beta-blockers. Approximately 1 in 4 patients (26.7%) were treated with multiple heart medications.
About 2% of DMD patients born before 1989 received preventive heart disease treatments — a percentage that increased to as high as 40% thereafter, the data showed.
Researchers call heart medication use ‘a topic of focus for improving care’
Overall, fewer patients given heart medications developed LVD, and those who did had a later onset of the condition, the data showed. Further, treated individuals used fewer corticosteroids and lost the ability to walk versus untreated patients at the same age. By contrast, more treated individuals started noninvasive breathing support, and at an earlier age, than untreated patients. The number of patients who underwent spinal surgery was similar between the two groups.
Preventive heart medications given before LVD extended survival in DMD because treated patients lived longer than untreated patients (median 26.4 vs. 23.3 years), according to the study.
In line with this result, more treated patients lived to age 25 than untreated patients (53.9% vs. 36.2%). After adjustments, the use of such treatments was associated with a 55% reduction in the risk of LVD onset.
The researchers noted that these findings were unaffected by various factors, such as the age at the first visit, MD STARnet site, corticosteroid use, clinical care over time, and the medication type prescribed.
Despite the compelling evidence of the benefit of prophylaxis in delaying [heart muscle disease], prophylactic use of cardiac medications in the United States has not been widely adopted. … Only one-quarter of individuals received [preventive] treatment.
When individuals born before 1989 were excluded from the analysis —done as a comparator because so few took these therapies — the relationship between preventive heart treatment and prolonged survival strengthened.
The researchers noted, however, that “despite the compelling evidence of the benefit of prophylaxis in delaying cardiomyopathy, prophylactic use of cardiac medications in the United States has not been widely adopted.” The study noted that “only one-quarter of individuals received [preventive] treatment.”
According to the team, these finding “[indicate] a topic of focus for improving care.”
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