Abstract
DMD causes progressive lethal respiratory muscle weakness and the long-term effects of cortico-steroids on respiratory function is still under debate.
We aim to investigate the effect of steroid therapy on a longitudinal study in our cohort of DMD patients.
Since 2006, we have been monitoring the respiratory function in 95 DMD patients (age range: 6-24 years) who were evaluated once per year until the age of 10-11 years or until wheelchair bounding and then twice per year after wheelchair bounding or first signs of respiratory or cardiac impairment, making a total of 429 evaluations. During every visit, forced vital capacity, nocturnal arterial oxygen saturation and the supine abdominal percentage contribution to resting tidal volume (an index of the action of the diaphragm1) were respectively measured with spirometry, pulse oximetry and opto-electronic plethysmography. 46 patients underwent continuous therapy with steroid for at least 2 years while 49 never assumed steroid or they did it for < 2 years and used as controls.
No differences (p=0.12) were found in forced vital capacity, nocturnal saturation and action of the diaphragm between the 231 evaluations of the steroid group and the 198 evaluations of the controls (figure).
The steroid therapy seems not to have ameliorative effects on the respiratory function decline in DMD patients.
1Lo Mauro et al, Eur Respir J. 2010 May;35(5):1118-25
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