BACKGROUND: Patients with asthma incur the risk of steroid-induced myopathy, which is a well-known side effect of treatment with corticosteroids. However, the adverse effect of long-term steroid treatment on respiratory muscle function remains controversial. OBJECTIVE: We aimed to evaluate the effects of long-term moderate dose of systemic corticosteroids and high-dose inhaled beclomethasone on maximal inspiratory and expiratory pressures (PImax and PEmax, respectively) in two groups of asthmatic patients exhibiting comparable levels of hyperinflation. METHODS: Twelve steroid-dependent asthmatic patients requiring 10-20 mg/day of prednisone-equivalent corticosteroids for an average of 9.83 +/- (SD) 9.86 years; 14 subjects with moderate to severe asthma who have used inhaled beclomethasone for at least 1 year at a daily dose higher than 1,000 microg and 15 healthy controls were included to the study. RESULTS: No significant difference in pulmonary function tests and arterial blood gases appeared between two asthmatic groups with different treatment modalities. PImax as an absolute value was significantly lower in steroid-dependent asthmatics than in patients treated with inhaled beclomethasone and controls (p < 0.01). %PImax was also lower in steroid-dependent asthmatics than in control groups (p < 0.01). A significant correlation was found between %PImax and hyperinflation assessed by %RV, %FRC, %FRC/TLC (p < 0.05) in all asthmatic patients. CONCLUSIONS: We believe that hyperinflation plays a major role in inspiratory muscle dysfunction in asthma, but the finding of significantly decreased PImax values in steroid-dependent asthmatics when compared with patients on high-dose inhaled beclomethasone with a comparable level of hyperinflation points to a deleterious effect of long-term, moderate-dose systemic corticosteroid but not high-dose beclomethasone on inspiratory muscle function in asthmatics.
BACKGROUND:Patients with asthma incur the risk of steroid-induced myopathy, which is a well-known side effect of treatment with corticosteroids. However, the adverse effect of long-term steroid treatment on respiratory muscle function remains controversial. OBJECTIVE: We aimed to evaluate the effects of long-term moderate dose of systemic corticosteroids and high-dose inhaled beclomethasone on maximal inspiratory and expiratory pressures (PImax and PEmax, respectively) in two groups of asthmatic patients exhibiting comparable levels of hyperinflation. METHODS: Twelve steroid-dependent asthmatic patients requiring 10-20 mg/day of prednisone-equivalent corticosteroids for an average of 9.83 +/- (SD) 9.86 years; 14 subjects with moderate to severe asthma who have used inhaled beclomethasone for at least 1 year at a daily dose higher than 1,000 microg and 15 healthy controls were included to the study. RESULTS: No significant difference in pulmonary function tests and arterial blood gases appeared between two asthmatic groups with different treatment modalities. PImax as an absolute value was significantly lower in steroid-dependent asthmatics than in patients treated with inhaled beclomethasone and controls (p < 0.01). %PImax was also lower in steroid-dependent asthmatics than in control groups (p < 0.01). A significant correlation was found between %PImax and hyperinflation assessed by %RV, %FRC, %FRC/TLC (p < 0.05) in all asthmatic patients. CONCLUSIONS: We believe that hyperinflation plays a major role in inspiratory muscle dysfunction in asthma, but the finding of significantly decreased PImax values in steroid-dependent asthmatics when compared with patients on high-dose inhaled beclomethasone with a comparable level of hyperinflation points to a deleterious effect of long-term, moderate-dose systemic corticosteroid but not high-dose beclomethasone on inspiratory muscle function in asthmatics.
Authors: Alessandra Maria Farias Cavalcante Marcelino; Daniele Andrade da Cunha; Renata Andrade da Cunha; Hilton Justino da Silva Journal: Int Arch Otorhinolaryngol Date: 2012-10