Can switching inhalers reduce your carbon footprint?

Patients who switched from a pressurized metered-dose inhaler (pMDI) to a dry powder inhaler (DPI) halved their carbon footprint while maintaining good asthma control, a post-hoc analysis showed from the Salford Lung Study in Asthma.

Including both asthma maintenance and reliever therapy, the annual equivalent carbon footprint per patient (CO2e) drop of a geometric least squares (LS) mean of 240 kg CO2e for those on pMDI at 108 kg CO2e with a DPI (PThorax.

For context, the carbon footprint of a flight from New York to Miami is approximately 215 kg CO2e per passenger.

“[The DPI] don’t lose control of your asthma – that’s the key. You actually improve asthma control,” said co-author Ashley Woodcock, MD, of the University of Manchester in England, in a BMJ podcast. “It’s a low-hanging fruit to reduce our carbon footprint.”

Around 70% of inhalers distributed in England are pMDIs, accounting for 3.5% of National Health Service greenhouse gas emissions.

The study group added that “the UK is an outlier compared to the rest of Europe in its continued high use of pMDIs”. A research letter 2020 by co-author Christer Janson, MD, PhD, of Uppsala University in Sweden, found that while England had the same pMDI distribution as Sweden, where pMDIs accounted for 13% of inhalers, the England would reduce its inhaler carbon footprint by 550 kilotonnes of CO2e.

the British Chest Society recommends using DPIs, but as the authors noted, switching to DPIs can be more expensive than using pMDI.

The study group examined a subset of data from an open study from 2017 led by Woodcock, where adults with asthma were randomized to either take fluticasone furoate/vilanterol (FF/VI) via the ELLIPTA DPI or continue usual care. The current study only included participants who used a pMDI before the study, totaling approximately half of the original study population (2,236 of 4,233).

Asthma control was measured with the Asthma Control Test (ACT) at baseline, 12, 24, 40, and 52 weeks of treatment. Rescue medication was measured as the total number of salbutamol/albuterol inhalers prescribed during the 12-month treatment period.

The primary endpoint was asthma control at 24 weeks. The carbon footprint has been determined using data from a 2019 study conducted by Janson’s group.

Study participants had a mean age of 49 years, 57-59% were female, and the mean ACT score at baseline was comparable between the groups (16.6 in the usual care group versus 16.5 in the group FF/VI).

While asthma control improved in both arms of the study, it was “consistently better over the 12 months” in participants randomized to the FF/VI DPI group, the group said. study. At 24 weeks, the odds of being an ACT responder—defined as having an ACT score greater than 19, indicating well-controlled asthma and/or improvement from baseline score ≥3—were almost twice as high in the FF/VI group compared to usual treatment group (76% vs 63%, adjusted OR 1.91, 95% CI 1.57-2.33, P

When considering maintenance treatment alone, the results were more pronounced. The carbon footprint in the FF/VI group was 10 times lower than in the usual care group (LS geometric mean of 11 kg versus 118 kg, respectively, P

In fact, the majority of the DPI group’s carbon footprint came from rescue drugs, Woodcock said.

Even so, patients who switched to PGD were on average prescribed almost one less salbutamol/albuterol rescue inhaler during the study period (mean LS of 7.2 versus 8 inhalers). This also translated to a lower carbon footprint of rescue medication in the DPI group (LS geometric mean of 88 kg DPI vs 109 kg usual care, P

  • Lei Lei Wu is an editor for Medpage Today. She is based in New Jersey. To follow


This analysis and editorial support was funded by GlaxoSmithKline R&D.

Woodcock disclosed GlaxoSmithKline and Novartis fees outside of the submitted work, in addition to being chairman and shareholder of Reacta Biotech.

Moore and several co-authors are employees of GlaxoSmithKline, which developed the ELLIPTA DPI.