Sleep Disordered Breathing in Young Boys with Duchenne Muscular Dystrophy

Objectives To describe sleep-disordered breathing (SDB) in young boys with Duchenne muscular dystrophy (DMD) and its relationship with pulmonary function tests (PFTs). Study design This retrospective study examined diagnostic polysomnogram and PFT data of boys younger than 18 years with DMD and treated with steroids. Spirometry, respiratory muscle strength, body mass index (BMI), sleep architecture variables, and indices of SDB were analyzed. We examined the effect of PFT measures on the risk of each type of respiratory event using logistic regression and have reported results as OR (95% CI). Results Subjects included 110 boys with DMD, mean age 11.5 (5.6-17.9) years. Mean (+/- SD) percent forced vital capacity predicted was 79.5% +/- 29.1%. Mean BMI for all subjects was 21.9 +/- 7.0 kg/m(2), and mean BMI z-score was 0.65 +/- 1.93. Seventy (63.6%) subjects had obstructive sleep apnea; 37 (33.6%) subjects had central sleep apnea; 18 (17%) subjects had hypoventilation. Median (IQR) Apnea Hypopnea Index was 2.9 (1.6-6.9) and median Obstructive Index was 1.5 (0.5-3.8). Obstructive Index during rapid eye movement sleep positively correlated with BMI (r = 0.33, P = .002), BMI z-score (r = 0.22, P = .04), and age (r = 0.31, P = .004). Lower forced vital capacity was associated with increased risk of hypoventilation (OR 0.8, P = .001). Conclusion SDB is common in young boys with DMD treated with steroids. It is manifest with rapid eye movement-obstructive sleep apnea, often severe, and strongly influenced by BMI.