BACKGROUND: Management of chronic obstructive pulmonary disease (COPD) commonly involves a combination of long-acting bronchodilators including beta2-agonists (LABA) and muscarinic antagonists (LAMA). LABA and LAMA bronchodilators are now available in single-combination inhalers. In individuals with persistent symptoms or frequent exacerbations, inhaled corticosteroids (ICS) are also used with combination LABA and LAMA inhalers. However, the benefits and risks of adding ICS to combination LABA/LAMA inhalers as a triple therapy remain unclear.
OBJECTIVES: To assess the effects of adding an ICS to combination LABA/LAMA inhalers for the treatment of stable COPD.
SEARCH METHODS: We searched the Cochrane Airways Group Register of Trials, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and Embase up to 30 November 2022. We also searched ClinicalTrials.gov and the WHO ICTRP up to 30 November 2022.
SELECTION CRITERIA: We included parallel-group randomised controlled trials of three weeks' duration or longer that compared the treatment of stable COPD with ICS in addition to combination LABA/LAMA inhalers against combination LABA/LAMA inhalers alone.
DATA COLLECTION AND ANALYSIS: We used standard Cochrane methodological procedures. The primary outcomes were acute exacerbations of COPD, respiratory health-related quality of life, pneumonia and other serious adverse events. The secondary outcomes were symptom scores, lung function, physical capacity, and mortality. We used GRADE to assess certainty of evidence for studies that contributed data to our prespecified outcomes.
MAIN RESULTS: Four studies with a total of 15,412 participants met the inclusion criteria. The mean age of study participants ranged from 64.4 to 65.3 years; the proportion of female participants ranged from 28% to 40%. Most participants had symptomatic COPD (COPD Assessment Test Score ≥ 10) with severe to very severe airflow limitation (forced expiratory volume in one second (FEV1) < 50% predicted) and one or more moderate-to-severe COPD exacerbations in the last 12 months. Trial medications differed amongst studies. The duration of follow-up was 52 weeks in three studies and 24 weeks in one study. We assessed the risk of selection, performance, and detection bias to be low in the included studies; one study was at high risk of attrition bias, and one study was at high risk of reporting bias. Triple therapy may reduce rates of moderate-to-severe COPD exacerbations compared to combination LABA/LAMA inhalers (rate ratio (RR) 0.74, 95% confidence interval (CI) 0.67 to 0.81; n = 15,397; low-certainty evidence). Subgroup analysis stratifying by blood eosinophil counts showed there may be a greater reduction in rate of moderate-to-severe COPD exacerbations with triple therapy in participants with high-eosinophils (RR 0.67, 95% CI 0.60 to 0.75) compared to low-eosinophils (RR 0.87, 95% CI 0.81 to 0.93) (test for subgroup differences: P < 0.01) (high/low cut-offs: 150 eosinophils/µL in three studies; 200 eosinophils/µL in one study). However, moderate-to-substantial heterogeneity was observed in both high- and low-eosinophil subgroups. These subgroup analyses are observational by nature and thus results should be interpreted with caution. Triple therapy may be associated with reduced rates of severe COPD exacerbations (RR 0.75, 95% CI 0.67 to 0.84; n = 14,131; low-certainty evidence). Triple therapy improved health-related quality of life assessed using the St George's Respiratory Questionnaire (SGRQ) by the minimal clinically important difference (MCID) threshold (4-point decrease) (35.3% versus 42.4%, odds ratio (OR) 1.35, 95% CI 1.26 to 1.45; n = 14,070; high-certainty evidence). Triple therapy may result in fewer symptoms measured using the Transition Dyspnoea Index (TDI) (OR 1.33, 95% CI 1.13 to 1.57; n = 3044; moderate-certainty evidence) and improved lung function as measured by change in trough FEV1 (mean difference 38.68 mL, 95% CI 22.58 to 54.77; n = 11,352; low-certainty evidence). However, these benefits fell below MCID thresholds for TDI (1-unit decrease) and trough FEV1 (100 mL), respectively. Triple therapy is probably associated with a higher risk of pneumonia as a serious adverse event compared to combination LABA/LAMA inhalers (3.3% versus 1.9%, OR 1.74, 95% CI 1.39 to 2.18; n = 15,412; moderate-certainty evidence). In contrast, all-cause serious adverse events may be similar between groups (19.7% versus 19.7%, OR 0.95, 95% CI 0.87 to 1.03; n = 15,412; low-certainty evidence). All-cause mortality may be lower with triple therapy (1.4% versus 2.0%, OR 0.70, 95% CI 0.54 to 0.90; n = 15,397; low-certainty evidence).
AUTHORS' CONCLUSIONS: The available evidence suggests that triple therapy may reduce rates of COPD exacerbations (low-certainty evidence) and results in an improvement in health-related quality of life (high-certainty evidence) compared to combination LABA/LAMA inhalers, but probably confers an increased pneumonia risk as a serious adverse event (moderate-certainty evidence). Triple therapy probably improves respiratory symptoms and may improve lung function (moderate- and low-certainty evidence, respectively); however, these benefits do not appear to be clinically significant. Triple therapy may reduce the risk of all-cause mortality compared to combination LABA/LAMA inhalers (low-certainty evidence). The certainty of the evidence was downgraded most frequently for inconsistency or indirectness. Across the four included studies, there were important differences in inclusion criteria, trial medications, and duration of follow-up. Investigation of heterogeneity was limited due to the small number of included studies. We found limited data on the effects of triple therapy compared to combination LABA/LAMA inhalers in patients with mild-moderate COPD and those without a recent exacerbation history.
