Figure 2 Mean relative change in FEV₁ % predicted from randomisation measurement in the whole population and in the subpopulations of patients not infected or infected with P aeruginosa. The error bars indicate the 95% confidence interval of the mean relative change. No significant difference was recorded between the two treatment groups (azithromycin or placebo), either in the whole population or in the subpopulations of patients not infected or infected with P aeruginosa.