Change from MDI to DPI in asthma: effects on climate emissions and disease control

Abstract

Background: The carbon footprint of a dry powder inhaler (DPI) is around 20 times lower than a hydrofluorocarbon pressurised metered-dose inhaler (pMDI). This post-hoc analysis compared the effects of switching from a pMDI-based to a DPI-based maintenance therapy with continued usual care (UC) therapy, on greenhouse gas emissions (CO₂e) and asthma control.

Methods: A subset of patients (N=2236/4233 [53%]) from the Salford Lung Study (SLS) in Asthma in which adult patients taking pMDI-based maintenance therapy were randomised to either fluticasone furoate/vilanterol (FF/VI) via a DPI (ELLIPTA) (N=1081) or continued UC treatment (N=1155), was analysed. Annual CO₂e (kg) was calculated for total number of maintenance and rescue therapy inhalers prescribed, using published data (Wilkinson et al. BMJ Open 2019;9:e028763; Janson et al. Thorax 2020;75:82-84). The proportion of Asthma Control Test (ACT) responders (composite of ACT total score ≥20 and/or increase from baseline ≥3) was assessed.

Results: Total CO₂e kg (maintenance plus rescue therapy) was significantly higher with UC (least square [LS] geometric mean [gMean] [95% confidence interval (CI)]: 240 [229, 252] kg) than FF/VI (108 [102, 114] kg); ratio of LS gMeans: 2.23, 95% CI (2.08, 2.39), p<0.001. ACT responders at Week 24 were 63% and 76% in the UC and FF/VI groups, respectively (adjusted odds ratio [95% CI]: 1.91 [1.57, 2.33], p<0.001).

Conclusions: In the subset of SLS patients on a pMDI-based asthma maintenance therapy who switched to DPI therapy (FF/VI), there was a substantial reduction in carbon footprint without loss of asthma control. Asthma control improved in both groups, with greater control demonstrated in those who initiated FF/VI.