LAUSR

Introduction: Ventilatory failure is the main cause of death in DMD. With the progression of the disease it is extremely important to monitor lung function in order to identify possible early signs of ventilatory insufficiency. Aims and objectives: To analyze the trends of spirometry and lung volume subdivision in order to identify possible milestones in the natural course of DMD. Methods: This is a 7-years retrospective analysis of spirometry and subdivisions of lung volume in 115 DMD patients with age ranging 6-24 years, evaluated once or twice per year, for a total of 597 visits. Results: Forced vital capacity (FVC), forced expiratory volume in 1sec (FEV 1 ) and peak expiratory flow (PEF) when expressed as percentage of the predicted values, linearly declined by 3.8%,4.5% and 3.4% per year, respectively. All lung volumes were lower than predicted since the age of 11. FVC reduced due to both inspiratory capacity and expiratory reserve volume(Figure1). Conclusions: In DMD, spirometric indexes and subdivisions of lung volumes when expressed as absolute values, although significantly lower than predicted all over the considered age span, did not show characteristic patterns useful for prognostic purposes. On the other hand, the same spirometric indexes showed a characteristic continuous and linear decay with age when expressed as percentage of predicted values.