Pulmonary Dysfunction in Children with Dystrophinopathy: A Cross-Sectional Study.

OBJECTIVES

To observe the prevalence of impaired pulmonary function during various phases of the disease course in children aged 5-18 y with dystrophinopathy. The correlation between different parameters of pulmonary dysfunction and motor function was also studied.

METHODS

One hundred and thirty-three confirmed cases of Duchenne muscular dystrophy (DMD), fulfilling predefined inclusion and exclusion criteria were evaluated. A pulmonary function test, the six-minute walk test (6MWT), and a functional assessment of muscular strength using the Vignos and Brooke functional scale were performed on all children. Pulmonary dysfunction was defined as < 80% of the predicted forced vital capacity (FVC).

RESULTS

The overall prevalence of pulmonary dysfunction was 48.12% (95% CI: 39.8-56.54). The prevalence (95% CI) of pulmonary dysfunction in age groups 5-7.5 y, 7.5-10 y, and 10-18 y was 50% (33.63-66.37), 39.29% (27.58-52.37), and 57.78% (43.3-71.03) respectively. There was a significant association of mean walk duration (r = 0.2509; p = 0.019), walk distance (r = 0.21; p = 0.028), Brooke functional score (r = -0.30; p = 0.0006), and Vignos functional score (r = -0.21; p = 0.019) with percentage predicted FVC. Children with deletion of R17, 18 and 19 spectrin-like repeats were found to have a significantly high proportion of pulmonary dysfunction (p = 0.006). No statistically significant differences were found between children with a deletion involving ABD or hinge region 3 and those without.

CONCLUSIONS

Impaired pulmonary function can be seen quite early in the disease course, and its prevalence is comparable to those of children with a long-standing disease.