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Original research
Effects of switching from a metered dose inhaler to a dry powder inhaler on climate emissions and asthma control: post-hoc analysis
  1. Ashley Woodcock1,
  2. Christer Janson2,
  3. Jamie Rees3,
  4. Lucy Frith3,
  5. Magnus Löfdahl4,
  6. Alison Moore5,
  7. Martin Hedberg6,
  8. David Leather5
  1. 1 Manchester Academic Health Sciences Centre, The University of Manchester, Manchester, UK
  2. 2 Department of Medical Sciences: Respiratory, Allergy & Sleep Research, Uppsala University, Uppsala, Sweden
  3. 3 Biostatistics, GlaxoSmithKline R&D, Brentford, UK
  4. 4 GlaxoSmithKline, Solna, Sweden
  5. 5 Respiratory Therapy Area, GlaxoSmithKline R&D, Brentford, UK
  6. 6 The Polyfuture Institute SWC AB, Nacka, Sweden
  1. Correspondence to Dr Alison Moore, GlaxoSmithKline plc., Brentford, UK; alison.c.moore{at}


Objective To compare the effects of switching from a pressurised metered dose inhaler (pMDI)-based to a dry powder inhaler (DPI)-based maintenance therapy versus continued usual care on greenhouse gas emissions (carbon dioxide equivalents, CO2e) and asthma control.

Methods This post-hoc analysis was based on a subset of 2236 (53%) patients from the Salford Lung Study in Asthma who at baseline were using a pMDI-based controller therapy. During the study patients were randomised to fluticasone furoate/vilanterol (FF/VI) via the ELLIPTA DPI (switched from pMDI to DPI) (n=1081) or continued their usual care treatment (n=1155), and were managed in conditions close to everyday clinical practice. Annual CO2e (kg) was calculated for the total number of maintenance and rescue inhalers prescribed. Asthma control was assessed by the proportion of ACT responders (composite of ACT total score ≥20 and/or increase from baseline ≥3).

Results The groups were well matched for demographic characteristics and baseline Asthma Control Test (ACT) total score (mean age: 49 years; mean ACT score: usual care, 16.6; FF/VI, 16.5). Annual CO2e kg per patient (maintenance plus rescue therapy) was significantly lower with FF/VI DPI treatment (‘switch’ group) than usual care (least squares geometric mean 108 kg (95% CI 102 to 114) vs 240 kg (95% CI 229 to 252), p<0.001). Asthma control was consistently superior over the 12 months in the FF/VI DPI group compared with usual care.

Conclusions Patients switching from a pMDI-based to a DPI-based maintenance therapy more than halved their inhaler carbon footprint without loss of asthma control. The remaining inhaler carbon footprint could be reduced through switches from pMDI to DPI rescue medications or alternative lower-carbon footprint rescue inhalers if available. Asthma control improved in both groups, with greater control demonstrated in those initiated on FF/VI DPI.

Trial registration number NCT01706198.

  • asthma
  • inhaler devices

Data availability statement

Data are available upon reasonable request. Information on GlaxoSmithKline R&D’s data sharing commitments and request access can be found at

This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See:

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Data availability statement

Data are available upon reasonable request. Information on GlaxoSmithKline R&D’s data sharing commitments and request access can be found at

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  • Contributors AAW, JR, LF, ML, AM and DL were involved in the study design and collection of data. JR and LF were responsible for data analysis. All authors were involved in the data interpretation and in the drafting, critical revision and approval of the manuscript. The corresponding author attests that all listed authors meet the authorship criteria and that no others meeting the criteria have been omitted. DL is the guarantor and affirms that the manuscript is an honest, accurate and transparent account of the study being reported and that no important aspects of the study have been omitted.

  • Funding This analysis and editorial support were funded by GlaxoSmithKline R&D.

  • Disclaimer GlaxoSmithKline-affiliated authors had a role in study design, collection of data, data interpretation and writing of the report.

  • Competing interests All authors have completed the ICMJE uniform disclosure form at and declare the following: AAW discloses speaker fees and expenses from GlaxoSmithKline and advisory expenses from Novartis, outside of the submitted work. He is also Chairman of, and shareholder in, Reacta Biotech. JR, DL, LF, ML and AM are employees of GSK and hold shares. MH has no conflicts of interest to declare. CJ reports personal fees from AstraZeneca, Boehringer Ingelheim, Chiesi, GlaxoSmithKline, Novartis and TEVA, outside the submitted work.

  • Provenance and peer review Not commissioned; externally peer reviewed.