Level 2: Mid-level evidence
The efficacy of inhaled corticosteroids for treating moderate-to-severe chronic obstructive pulmonary disease (COPD) was evaluated in a systematic review of 13 randomized placebo-controlled trials (Ann Fam Med. 2006;4:253-262; full-text available online free of charge at www.annfammed.org/cgi/content/full/4/3/253. Accessed January 9, 2007). Trial participants were outpatients who were followed for at least six months. Quality ratings were good for three of the trials and fair for nine of the trials. One trial was excluded from analyses due to multiple postrandomization exclusions.
Based on meta-analyses comparing inhaled corticosteroids with placebo, inhaled corticosteroids were associated with a 33% relative risk reduction in COPD exacerbation rates over a mean follow-up of 21 months in 2,300 patients in 10 trials. Absolute risks were not reported for the overall analysis. The estimated benefit in patients with moderate-to-severe COPD was NNT 12 (95% confidence interval [CI] 9-18), based on seven trials with mean follow-up of 18 months. There was no significant effect reported in three trials involving 191 patients with mild COPD, but the confidence intervals were wide and a clinically significant benefit cannot be excluded. The rates of overall mortality in 4,370 patients with mean follow-up 22 months were not statistically significant: 2.5% with inhaled corticosteroids vs. 2.9% with placebo (relative risk 0.81, 95% CI 0.6-1.08).
There were no conclusive findings for outcomes related to functional capacity, quality of life, or respiratory symptoms. Five trials evaluated functional capacity and quality of life, but they were too heterogeneous to assess in a meta-analysis. For respiratory symptoms, one trial reported lower symptoms, four trials reported no difference, and three trials reported no difference in overall symptoms but reductions in specific symptoms.