Inhaled corticosteroids (ICS) have been shown to decrease the occurrence of COPD exacerbations. However, the relationship of baseline lung function and reduction of exacerbations with the use of ICS remains unknown. Herein, we perform a metaregression to evaluate the efficacy of ICS in preventing COPD exacerbations.
We searched the PubMed, EmBase, and Cochrane Central Database of Controlled Trials databases (1988-2008) for studies that have reported the efficacy of ICS vs placebo in preventing COPD exacerbations. We pooled the risk ratio (RR) and 95% CIs from individual studies using a random-effects model to assess the exacerbations in the two groups. We also performed a weighted random effects metaregression using baseline FEV1 values.
Our search yielded 11 studies (8,164 patients). The use of ICS was associated with reduction in the occurrence of exacerbations (RR, 0.82; 95% CI, 0.73-0.92). There was the presence of significant statistical heterogeneity but no evidence of publication bias. Sensitivity analysis revealed benefit of ICS only in patients with FEV1 < 50% (RR, 0.79; 95% CI, 0.69-0.89) with persistence of statistical heterogeneity. Metaregression showed that the percentage risk reduction in exacerbations with the use of ICS is invariant across the severity of COPD (assessed by FEV1).
There is only a modest benefit of ICS in preventing COPD exacerbations, which is not related to the level of baseline lung function on metaregression analysis. The benefits of ICS in preventing COPD exacerbations thus seem to be overstated.