Parallel, randomised controlled trials (RCTs) of long-acting inhaled bronchodilator therapy (monotherapy) in adult patients (35 years or older) with stable chronic obstructive pulmonary disease, chronic bronchitis or emphysema were eligible for inclusion if they reported FEV1 and health status, dyspnoea or exacerbations. Comparators could include placebo, long-acting beta-2 agonists (LABA), long-acting muscarinic antagonists (LAMA), LABA plus LAMA, and methylxanthines. Trials were required to last at least 12 weeks. The primary outcome was the St George's Respiratory Questionnaire (SGRQ) total score. Trials that had mixed populations were excluded unless separate data were reported for patients with chronic obstructive pulmonary disease.
All included trials were of LAMA (tiotropium), LABA (salmeterol, formoterol, or arformoterol), or both, with or without placebo. Mean age ranged from 60 to 74 years, with the percentage of male patients ranging from 48 to 88. Where reported, smoking history ranged from 31.5 to 68.4 pack years and FEV1 percentage predicted ranged from 33.3 to 73.4.
Two reviewers independently selected trials; any disagreements were resolved through discussion and checked by a third reviewer.