title: Changes in spirometry over time as a prognostic marker in patients with Duchenne muscular dystrophy.
abstract: Duchenne muscular dystrophy (DMD) causes a progressive impairment of muscle function leading to hypercapnic respiratory failure. Most studies of respiratory function in DMD have been cross-sectional rather than longitudinal, and these data have not been related to survival. We retrospectively studied 58 patients with DMD with at least 2 yr of follow-up spirometry and known vital status. Spirometry was abnormal at entry: median FEV(1) 1.60 L (range 0.4 to 2.6 L), FVC 1.65 L (range 0.45 to 2.75 L), FVC 64% predicted (range 29 to 97%). Individual rates of change of vital capacity varied, with a median annual change of -0.18 L (range 0.04 to -0.74 L), -8.0% predicted FVC (range 2 to -39%). During the study 37 patients died; the median age of death, calculated by Kaplan-Meier analysis, was 21.5 yr (range 15 to 28.5 yr). The age when vital capacity fell below 1 L was a strong marker of subsequent mortality (5-yr survival 8%). The maximal vital capacity recorded and its rate of decline (however expressed) predicted survival time. Repeated spirometric measurement provides a simple and relatively powerful means of assessing disease progression in these patients and should be considered when planning treatment trials.
authors.affiliation: Pulmonary and Rehabilitation Research Group, University Hospital Aintree, Fazakerley, Liverpool, United Kingdom.
authors.forename: M F
authors.initials: MF
authors.lastname: Phillips
authors.forename: R C
authors.initials: RC
authors.lastname: Quinlivan
authors.forename: R H
authors.initials: RH
authors.lastname: Edwards
authors.forename: P M
authors.initials: PM
authors.lastname: Calverley
mesh_terms: D000293:Adolescent; D002648:Child; D018450:Disease Progression; D004576:Electromyography; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D020388:Muscular Dystrophy, Duchenne / Q000150:complications / Q000401:mortality / Q000503:physiopathology*; D011379:Prognosis; D012131:Respiratory Insufficiency / Q000175:diagnosis / Q000209:etiology; D012132:Respiratory Muscles / Q000503:physiopathology; D012189:Retrospective Studies; D013147:Spirometry; D015996:Survival Rate; D014797:Vital Capacity