Chronic respiratory failure in myotonic dystrophy type 1 (DM1): Incidence & risk factors

Background: DM1 is the most frequent adult-onset muscular dystrophy. CTG length expansion has been correlated with disease severity. Incidence of chronic respiratory failure (CRF) is unknown. The aim of this study was to assess the incidence of CRF and its risk factors. Methods: Retrospective single center observational study including all patients with proven DM1 followed in Rouen University Hospital between 2000 and 2016. CRF was defined by home NIV requirement. Results: Eighty-six patients with DM1 were identified. Of these, 26 (30%) had CRF. Comparison of patients with or without CRF can be found in table 1. Adherence to home NIV was 5.6±3.6hours/day. CTG length was correlated to daytime PaCO 2 (r=0.366; p=0.01), sniff nasal inspiratory pressure (SNIP) (r=-0.391; p=0.008), maximal inspiratory pressure (MIP) (r=-0.530; p=0.001), maximal expiratory pressure (MEP) (r=-0.512; p=0.001) and cough peak flow (CPF) (r=-0.433; p=0.015). Conclusion: CRF is frequent in patients with DM1 and should be screened in all patients. CTG length expansion is correlated with respiratory muscles impairment but cannot predict home NIV requirement.