Cardiac involvement in Duchenne and Becker muscular dystrophies: a comparative study on long-term prognosis
J Lee, J W SeoAbstract
Background
In Duchenne Muscular Dystrophy (DMD) and Becker Muscular Dystrophy (BMD), cardiac involvement is prevalent and has significant implications for unfavorable prognosis. However, a comparative analysis of the two disease remains scarce in existing literature.
Purpose
We sought to identify differences in long-term prognosis based on the presence of cardiac involvement in patients with DMD and BMB.
Methods
We enrolled 178 subjects who underwent echocardiography at the time of DMD or BMD diagnosis. Diagnosis of DMD and BMD was confirmed through genetic testing and muscle biopsy. Cardiac involvement was defined as left ventricular ejection fraction (LVEF) < 50% at baseline echocardiography, and all cause-death was confirmed using the database from the Statistics Korea.
Results
Among 178 subjects, 118 were DMD and 60 were BMD. The average of age was 22.1 ± 8.7, all patients with DMD were male and two with BMD were female. On initial echocardiography, 37% of BMD (n=22) and 47% of DMD (n=56) had LVEF <50%. BMD patients with LVEF<50% had a mean LVEF of 35.5 ± 12.2 and DMD patients with LVEF<50% had a mean LVEF of 36.8 ± 10.5. The levels of B-type natriuretic peptide (BNP) was 62.9 ± 65.0 in BMD patients with reduced LVEF and 68.8 ± 77.4 in DMD patients. During a follow-up period (median 12 years), 41 all-cause death occurred. In Kaplan-Meier analysis, DMD patients had a worse prognosis than BMD patients. When stratified into four groups according to LVEF and muscular dystrophy type, the prognosis was more unfavorable for BMD patients with an initial LVEF <50%, aligning closely with the prognosis observed in DMD patients, compared with BMD patients with initial LVEF ≥50%.
Conclusion
More than one-third of BMD patients have initially decreased LVEF, and their BNP and LVEF reductions are similar to those of DMD. If there is cardiac involvement in BMD, the prognosis is comparable to that of DMD patients. Therefore, an initial cardiac workup is essential in BMD patients.For image description, please refer to the figure legend and surrounding text.