Nine RCTs (n=3,976) were included in the review.
The results of the validity assessment were not reported for each trial, but it was stated that 5 of the 6 trials that reported COPD exacerbation rates scored the maximum of five on the Jadad scale; the other study scored three points.
COPD exacerbations (6 RCTs).
The use of inhaled corticosteroids was associated with a 30% reduction in exacerbations (RR 0.70, 95% CI: 0.58, 0.84). The authors stated that the benefits were similar in patients receiving or not receiving systemic corticosteroids during the run-in phase, and in patients suffering one or more exacerbations. However, in the subgroup of studies in which patients received systematic steroids during the run-in phase, the difference between the groups was not significant (RR 0.77, 95% CI: 0.56, 1.09).
The test for heterogeneity was significant (P=0.03). This was thought to be due to one study which defined exacerbation differently from the others. When this study was omitted from the analysis, heterogeneity was no longer present (P=0.79) and the result was similar (RR 0.67, 95% CI: 0.63, 0.71). Sensitivity analysis revealed no dose-response effect.
All-cause mortality (5 RCTs).
There was no significant difference between groups (RR 0.84, 95% CI: 0.60, 1.18) and no significant heterogeneity (P=0.99).
FEV1 (9 RCTs).
The results were variable. Only 2 of the 9 trials found a statistically significant difference between the groups.
Adverse effects.
The authors reported that the frequencies of oropharyngeal candidiasis (RR 2.1, 95% CI: 1.5, 3.1) and skin bruising (RR 2.1, 95% CI: 1.6, 2.8) were increased in patients treated with corticosteroids but it was unclear how many trials reported on these effects. Effects on bone mineral density and cortisol concentrations were reported to be variable, while no differences in the rate of cataract or fracture were found.