Corticosteroids and skeletal muscle function in cystic fibrosis

• Published in: Journal of applied physiology (1985) 2003-10, Vol.95 (4), p.1379-1384
• Main Authors: Barry, Sinead C, Gallagher, Charles G
• Format: Article
• Language: English
• Subjects: Administration, Oral; Adrenal Cortex Hormones - adverse effects; Adult; Aging; Biological and medical sciences; Body Mass Index; Cystic fibrosis; Cystic Fibrosis - drug therapy; Cystic Fibrosis - physiopathology; Extremities; Female; Forced Expiratory Volume; Gastroenterology. Liver. Pancreas. Abdomen; Glucocorticoids - administration & dosage; Humans; Hydrocortisone - administration & dosage; Injections, Intravenous; Length of Stay; Liver. Biliary tract. Portal circulation. Exocrine pancreas; Male; Medical sciences; Muscle, Skeletal - drug effects; Muscle, Skeletal - physiopathology; Muscular system; Other diseases. Semiology; Prednisolone - administration & dosage; Regression Analysis; Respiratory Muscles - physiopathology; Respiratory system; Steroids
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.00506.2002

Department of Respiratory Medicine and the National Referral Centre for Adult Cystic Fibrosis, St. Vincent's University Hospital, Dublin 4, Ireland Submitted 11 June 2002 ; accepted in final form 30 May 2003 Patients with cystic fibrosis (CF) have reduced peripheral muscle strength. We tested the hypothesis that steroid treatment contributes to muscle weakness in adults with CF. Twenty-three stable CF patients were studied. Measurements included knee extensor (KE), knee flexor (KF), elbow flexor (EF), handgrip (HG), expiratory (P E max ), and inspiratory (P I max ) muscle strengths. Spirometry, body mass index (BMI), and days spent in hospital over the preceding 12 mo (DH) were also measured. Average daily dose of prednisolone over the preceding 12 mo (ADD) was 5.1 mg/day. Pearson's correlation analysis revealed that ADD correlated significantly with skeletal muscle strengths (KF%, r = -0.63, P < 0.01) with the exception of HG%. These findings are independent of age, BMI, pulmonary function, and DH. Multiple-regression analysis revealed that ADD was the most significant predictor of all measures of skeletal muscle function except HG%. It was independently responsible for 54% of the variance in P I max %, for 46% of the variance in P E max %, for 45% of the variance in KE%, for 39% of the variance in KF%, and for 41% of the variance in EF%. Concomitant medications (e.g., theophylline) were shown to have no causative effect. Corticosteroids contribute to the skeletal muscle weakness seen in CF patients. The correlation of proximal muscle strength, but not HG strength, with steroid dosage further supports a cause-effect relationship. steroids; peripheral muscle strength; respiratory muscle strength Address for reprint requests and other correspondence: C. G. Gallagher, Dept. of Respiratory Medicine, St. Vincent's Univ. Hospital, Dublin 4, Ireland (E-mail: v.hearn{at}st-vincents.ie ).