Forest plot meta-analysis of the impact of long-acting β2-agonist (LABA)/long-acting muscarinic antagonist (LAMA) fixed-dose combinations on changes in trough forced expiratory volume in 1 s (FEV1) at 3, 6 and 12 months. Forest plot meta-analysis of the impact of long-acting β2-agonist (LABA)/long-acting muscarinic antagonist (LAMA) fixed-dose combinations on changes in trough forced expiratory volume in 1 s (FEV1) at 3, 6 and 12 months. Data are presented as mean difference (95% CI) versus monocomponents. Luigino Calzetta et al. Eur Respir Rev 2017;26:160043 ©2017 by European Respiratory Society