Efficacy and safety of different inhaler types for asthma and chronic obstructive pulmonary disease. a systematic review and meta-analysis

Pressurised metered dose inhalers (pMDIs) contain propellant gases with high global warming potential yet remain a cornerstone of management for asthma and chronic obstructive pulmonary disease (COPD). The aim of this study was to determine whether non-propellant alternatives of dry powder inhalers (DPIs) and soft mist inhalers (SMIs) had similar efficacy and safety. A systematic review was performed finding 44 randomised trials (24,710 participants) and moderate certainty evidence for most outcomes. No statistically significant or clinically important differences were found between inhaler types for any assessed measure. For asthma maintenance, the mean difference in peak expiratory flow rate between groups was 1.07 L/min (95% confidence interval [CI] -0.93 to 3.06). For COPD, the mean difference in FEV₁ between groups was 0.01 L (95% CI -0.01 to 0.02). While the choice of optimal inhaler for an individual patient is a multifaceted decision, this review provides reassurance that non-pMDI devices can perform equally well.