Fig. 5

Meta-analysis of the effect of β₂-agonists on exercise-induced FEV₁ declines a) on the absolute scale, b) on the relative scale based on the absolute scale, and c) on the relative scale based on the slopes of linear regression models. See Additional file 1: Table S3 for the description of the calculation of the 95% CIs. In the forest plot on the right-hand side, the vertical line indicates the placebo test level. The horizontal lines indicate the 95% CI for the β₂-agonist effect in the particular trials and the square in the middle of the horizontal lines indicate the point estimate of the effect in the trial. The sizes of the squares indicate the relative weights of the trials in the pooling of the results. The diamond shape indicates the pooled effect and its 95% CI. The generic inverse variance and random effects options of the RevMan program were used [3]. See Additional file 1 for the details of the calculations