Respiratory and Sleep Disorders in 44 Spanish Patients with Myotonic Dystrophy Type I

Objectives: Myotonic dystrophy type 1 (DM1) is characterized by multisystemic effects that include frequent respiratory impairment that can affect prognosis. Despite this, there are not many studies specifically evaluating such alterations and no one from Spain. The aim of this study is to evaluate respiratory impairment in a Spanish group of patients with DM1. Materials and methods: Respiratory data were systematically collected from all patients with DM1 referred to a pulmonary clinic between June 2009 and June 2016. All patients completed the Epworth Sleepiness Scale and underwent forced spirometry test, cardiorespiratory polygraphy and blood gas analysis. Results: 44 patients were evaluated. 21 (48%) had a ventilatory impairment. 14 (31%) had hypoxemia, 2 (4%) respiratory failure and 14 (31%) hypercapnia. 39 (87%) had obstructive sleep apnoea, 40% being severe, and 18 (40%) showed nocturnal hypoventilation. A relationship between ventilatory impairment and blood gas alterations was found. It was found a relationship between ventilatory impairment and OSA. 31 (69%) were treated with a respiratory device. Adherence was poor. Conclusions: In this cohort of patients, the prevalence of ventilatory impairment and sleep breathing disorders were high. A careful respiratory evaluation, including assessment of sleep breathing, is advisable in patients with DM-1.