Inhaled corticosteroids slow progression of chronic obstructive pulmonary disease by up to 30%, a new study has shown.
Emphysema, bronchitis, and bronchiectasis are the most common types of chronic obstructive pulmonary disease. Over time, patients develop dyspnoea and increased susceptibility to lung infections and may become dependent on supplemental oxygen.
Although doctors commonly treat exacerbations of the disease with steroids, it has been unclear whether such treatment has long term benefits.
Researchers led by Dr Erika Sutherland of the University of Colorado Health Science Center in Denver sought to answer this question by conducting a meta-analysis of randomised controlled trials examining the effect of inhaled steroids on chronic obstructive pulmonary disease (Thora x 2003;58:937-41).
The researchers included only trials that excluded people with asthma, had a minimum follow up of one year, and measured the change in forced expiratory volume in one second (FEV1). Eight studies involving 3715 patients monitored over two years were included in the analysis.
The study arms compared inhaled steroids with placebo and with inhaled bronchodilators. Both smokers and non-smokers were included in the studies.
Overall, the meta-analysis found that inhaled corticosteroids significantly reduced the rate of the decline in FEV1 by 7.7 ml/year (95% confidence interval 1.3 to 14.2 ml/year, P=0.02).
The effect was even greater with higher dose steroid regimens: meta-analysis of 2416 high dose regimens found a mean reduction in decline of FEV1 of 9.9 ml/year (2.3 to 17.5 9.9 ml/year, P=0.01) compared with the meta-analysis of all studies.
The beneficial effects of inhaled steroids were greatest in non-smokers who had taken the drugs for at least two years. In these smokers the reduction in the rate of decline of FEV1 was 26-33% compared with those taking placebo. Subjects who continued to smoke also improved, however, with a 13-17% reduction in rate of decline.
The authors suggest that corticosteroids modify the effects of disease because chronic obstructive pulmonary disease has an underlying inflammatory component.