Abstract: We included two studies with 880 participants. We identified one ongoing trial with planned recruitment of 80 participants. Included studies enrolled participants with both partially reversible and non-reversible COPD and baseline mean per cent predicted (%pred) forced expiratory volume in one second (FEV₁) of 43.4 to 49.6. Both studies lasted 12 weeks. Both studies used the same combination of inhaled ICS/LABA (fluticasone furoate and vilanterol 100/25 mcg once daily; FF/VI) versus LAMA (18 mcg tiotropium; TIO). They were published as full articles, and neither study was at low risk of bias in all domains. Compared to the TIO arm, results for pooled primary outcomes for the FF/VI arm were as follows: mortality: OR 0.20, 95% CI 0.02 to 1.73, 880 participants (deaths reported only in the TIO arm), very low-quality evidence; COPD exacerbation (requiring short-burst oral corticosteroids or antibiotics, or both): OR 0.72, 95% Cl 0.35 to 1.50, 880 participants, very low-quality evidence; pneumonia: reported in both studies only during treatment with FF/VI: OR 6.12, 95% Cl 0.73 to 51.24, 880 participants, very low-quality evidence; and total serious adverse events: OR 0.96, 95% Cl 0.50 to 1.83, 880 participants, very low-quality evidence. None of the pneumonias were fatal. Compared to the TIO arm, we found no statistically significant difference for pooled secondary outcomes, including St George's Respiratory Questionnaire (SGRQ) mean total score change; hospital admissions (all-cause); disease-specific adverse events; mean weekly rescue medication use (results available from only one of the studies); and mean weekly percentage of rescue-free days for FF/VI. We found no statistically significant differences between ICS/LABA and LAMA for improvement in symptoms measured by the COPD Assessment Test (CAT score) nor for FEV₁ (change from baseline trough in 24-hour weighted mean on treatment day 84). Many pooled estimates lacked precision. Data for other endpoints such as exacerbations leading to intubation and physical activity measures were not available in included trials. Based on analysis of primary and secondary outcomes, we are uncertain whether once-daily ICS/LABA, combined in one inhaler, has a different efficacy or adverse effect profile compared to LAMA for treatment of people with COPD. However, the current review is based on only two trials with the main focus on primary outcomes other than those considered in this review. The short follow-up period and the very low quality of evidence limit our confidence in the result and increase uncertainty. Further trials of longer duration are needed. Current evidence is not strong enough to demonstrate important differences between inhalers in terms of effects, nor to establish that once-daily fluticasone/vilanterol 100/25 mcg and tiotropium 18 mcg are equivalent.

Plain-language summary: We found two studies involving 880 participants that compared the benefits and harms of once-daily inhaled ICS/LABA combined in one inhaler versus inhaled LAMA for treatment of adults with COPD. These studies lasted 12 weeks. Participants were men and women aged 40 or older who had COPD with various degrees of severity. No consistent differences were found between the two different types of inhalers included in this review. Researchers reported no major differences in death rate, numbers of COPD exacerbations, lung inflammation, or other serious unwanted events.  People receiving both inhalers showed similar improvements in quality of life, symptoms, and lung function tests. Overall, we assessed the evidence presented in this review to be of very low quality, which means we have very little confidence in the findings. The main reasons for such judgement include the small number of identified studies and the fact that these studies were not focused on the outcomes of interest for this review. Also, both studies had a short observation time, which means that most of the undesired events may have occurred after the observation period was over. From this review, we did not find evidence strong enough to demonstrate major differences between inhalers or to establish that these inhalers have the same effect.