A systematic review of the clinical effectiveness of dry powder inhalers in maintenance treatment and in treatment of acute exacerbations of asthma in children.

Background: Dry powder inhalers (DPIs) are a lower-carbon option than pressurised metered dose inhalers (pMDIs). However, DPIs require a forceful inhalation to achieve good lung deposition and there is uncertainty as to whether younger children can effectively use DPIs for maintenance treatment or rely upon them during exacerbations.

Methods: We searched electronic databases to identify randomised trials of children with asthma receiving treatment delivered via DPI, either for maintenance treatment (children ≤ 12 years) or for an acute exacerbation (participants up to age 18). Screening and data extraction were carried out by two reviewers. Risk of bias (RoB) assessment was made using the Cochrane RoB2 tool. Findings were narratively synthesised and a modified GRADE approach was taken to summarise the strength of evidence.

Results: 27 studies were included. 20 addressed maintenance treatment in children ≤ 12 years although only 4 compared the same treatment delivered via pMDI to DPI. All found no difference in efficacy between the device types (high certainty evidence). Other studies provided weaker, indirect evidence supporting this finding. 7 studies considered acute asthma in hospital/emergency settings. All reported no difference in efficacy between device types but certainty of evidence was low due to high RoB and clinical and methodological heterogeneity.

Conclusion: There are few studies directly comparing treatment via DPI/pMDI for asthma in children. Comparative studies suggest that for children who can use both DPI/pMDI, the devices are equal in efficacy for maintenance treatment in children ≤ 12 years but high-quality evidence is lacking regarding their use during acute exacerbations. This review did not find sufficient evidence to identify a lower age at which DPIs can start being used.