Copyright ©ERS Journals Ltd 2004 Acute effect of oral steroids on muscle function in chronic obstructive pulmonary disease1 Respiratory Muscle Laboratory, Royal Brompton Hospital, and 2 Dept of Respiratory Medicine, King's College Hospital, London, UK CORRESPONDENCE: N. Hopkinson, Respiratory Muscle Laboratory, Royal Brompton Hospital, London SW3 6NP, UK. Fax: 44 2073518939. E-mail: n.hopkinson@ic.ac.uk Keywords: Chronic obstructive pulmonary disease, corticosteroids, diaphragm, exercise, magnetic stimulation, quadriceps
Received: December 16, 2003
N. Hopkinson is funded by the Wellcome Trust, W. Man by the Medical Research Council, A. Nickol by the British Lung Foundation, E. Ross by the Cystic Fibrosis Trust and M. Dayer by the British Heart Foundation. M. Polkey's COPD research is part of the European Union European network for investigating the global mechanisms of muscle abnormalities in COPD (ENIGMA) Project (Grant no: QLK6-CT-2002-02285).
Prospective data to support the hypothesis that corticosteroids are a significant cause of muscle weakness in patients with chronic obstructive pulmonary disease (COPD) are lacking.
The authors studied respiratory and quadriceps muscle function, using both volitional techniques and magnetic nerve stimulation, as well as measuring metabolic parameters during incremental cycle ergometry, in 25 stable COPD patients. The forced expiratory volume in one second was 37.6±21.4 % predicted, before and after a 2-week course of o.d. prednisolone 30 mg. Quadriceps strength was also assessed in 15 control patients on two occasions.
Only two patients met the British Thoracic Society definition of steroid responsiveness. There was no change either in sniff transdiaphragmatic pressure (pre: 96.8±19.7 cmH2O; post: 98.6±22.4 cmH2O) or in twitch transdiaphragmatic pressure elicited by bilateral anterolateral magnetic phrenic-nerve stimulation (pre: 16.8±9.1 cmH2O; post: 17.9±10 cmH2O). Quadriceps twitch force did not change significantly either in the steroid group (pre: 9.5±3.1 kg; post: 8.9±3.7 kg) or in the control patients (pre: 8.1±2.7 kg; post: 7.9±2.2 kg). There were no changes in either peak or isotime ventilatory and metabolic parameters during exercise.
In conclusion, in stable patients with chronic obstructive pulmonary disease, a 2-week course of 30 mg prednisolone daily does not cause significant skeletal muscle dysfunction or alter metabolic parameters during exercise.
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