Sleep-disordered Breathing and Effects of Non-invasive Ventilation on Objective Sleep and Nocturnal Respiration in Patients with Myotonic Dystrophy Type I

Patients with myotonic dystrophy type I (DM1) may develop nocturnal hypoventilation, requiring non-invasive ventilation. Data on long-term adherence to non-invasive ventilation, or sleep and ventilation outcomes are scarce. We retrospectively collected baseline polysomnography and capnometry results from 36 adult patients with sleep-related symptoms (42.9 ± 12.5 years, 20 female), plus follow-up sleep study records from those treated with non-invasive ventilation. Sleep-disordered breathing was found in 33 patients (91.7%) including 8 (22.2%) with daytime hypercapnia. Twenty-six patients (72.2%) showed nocturnal hypoventilation on transcutaneous capnometry. The sensitivity of oximetry to detect nocturnal hypoventilation was only 0.38. Twenty-eight patients (77.8%) showed sleep apnea, which was predominantly obstructive (n = 8), central (n = 9), or "mixed" (n = 11). Thirty-two patients were initiated on non-invasive ventilation which significantly improved ventilation and oxygenation in the first night of treatment. Follow-up revealed stable normoxia and normocapnia without deterioration of sleep outcomes for up to 52 months. Adherence to treatment was low to moderate, with substantial inter-individual variability. Sleep disordered breathing is highly prevalent in adult DM1 patients complaining of daytime sleepiness, and non-invasive ventilation significantly, rapidly and persistently improves nocturnal gas exchange. Capnometry is superior to oximetry for detection of nocturnal hypoventilation. Adherence to non-invasive ventilation remains a major issue in DM1, and long-term treatment benefits should be individually assessed.