Longitudinal course of lung function in myotonic dystrophy type 1.

INTRODUCTION: Quality of life and prognosis among patients with myotonic dystrophy type 1 (DM1) depend on the degree of respiratory impairment. However, the changes over time in pulmonary function in DM1 have not been clearly described.

METHODS: We retrospectively reviewed pulmonary function tests of 80 DM1 patients followed for at least 5 years.

RESULTS: During 9.02 ± 3.4 years of follow-up, the average annual changes were: forced vital capacity (FVC) -0.034 ± 0.06 L (-0.72 ± 1.7% predicted); forced expiratory volume in 1 second (FEV1 ) -0.043 ± 0.05 L (-1.07 ± 1.7% predicted); and total lung capacity (TLC) -0.047 ± 0.1 L (-1.15 ± 1.7% predicted).

CONCLUSIONS: These results suggest that, compared with other neuromuscular disorders, DM1 is, overall, associated with slowly progressive impairment of lung function. Muscle Nerve 56: 816-818, 2017.