There is a good correlation between lung function and the function of the skeletal muscle in the arms and legs in patients with Duchenne muscular dystrophy (DMD), found a new study that appeared in the journal Pediatric Pulmonology.
This is the first study that explores the link between functional measures assessing skeletal muscle disease and lung function at the same time.
Read more about the symptoms of DMD and other muscular dystrophies
Patients with DMD underwent accelerometry and quantitative muscle testing at the time of their clinic visit at Vanderbilt University Medical Center in Nashville, Tennessee. Then, researchers led by Jonathan H. Soslow MD, MSCI, obtained the pulmonary function testing that the patients may have undergone in the last 6 months, from their medical records. They assessed the relationship between spirometry and functional muscle testing using the Spearman correlation coefficient.
They found the strongest correlation between forced vital capacity and forced expiratory volume in 1 second and the results of accelerometry. Both measures of lung function showed a similar relationship with accelerometry when the activity was divided into categories based on intensity. The strongest correlation was seen with low-intensity and moderate-to-vigorous activity categories.
Finally, the researchers found that the maximal expiratory pressure and forced vital capacity showed the most robust correlations with total quantitative muscle testing.
“Lung function . . . shows a good correlation with upper and lower extremity skeletal muscle functional testing such as accelerometry and [quantitative muscle testing],” they concluded.
DMD is a rare genetic disease caused by a mutation in the DMD gene situated on the X-chromosome. This gene codes for an essential protein called dystrophin. The disease is associated with progressive muscle weakness and respiratory decline mostly affecting boys. As the disease progresses patients lose the ability to walk and eventually rely on a ventilator to be able to breathe.
Kaslow JA, Sokolow AG, Donnelly T, et al. Spirometry correlates with physical activity in patients with Duchenne muscular dystrophy. Pediatr Pulmonol. Published online December 26, 2022. doi:10.1002/ppul.26289