Minimising the environmental impact of inhaled therapies: problems with policy on low carbon inhalers

From the authors:

We thank L. Lehtimäki and colleagues for their letter, and acknowledge and apologise for the error they identify relating to the country of the study [1]. All respiratory inhaled treatments are a combination of the drug and device, and we cited the Icelandic study to illustrate that an enforced switch of treatment by the government, here to low-cost alternatives, led to poorer clinical outcomes [1]. In this context, the mandated recommendations of the UK government for environmental reasons, give cause for concern. Our editorial stresses the necessity for patient engagement and choice, as well as clinical efficacy, to be considered in all steps of inhaler prescribing.

Non-consensual switches may result in discontent and lack of confidence amongst patients, and it has been suggested that patients with stable respiratory disease remain on their current inhaler device [2]. Prescribers must therefore take account of their patient's preference, and data show patients prefer an aqueous-based aerosol device rather than a dry-powder aerosol in comparative inhaler device studies with the same therapeutic drug [3, 4]. Efficacy data from real-world studies have suggested that the dry-powder inhaler (DPI) device with the same drug components gives poorer patient outcomes in asthma and COPD, compared to a pressurised metered dose inhaler (pMDI) [5, 6]. One inhaler does not fit all, so prescribers should choose a device that is tailored to patients’ individual and specific needs.

A UK prescribing cost analysis model indeed suggested the possibility of cost savings with increased use of DPIs, but this was dependent on prescribers using the lowest cost alternatives when switching, with significant cost increases should that not be the case [7]. Globally, continued access to low-cost inhalers will be vital for prescribers in low-income countries. We also highlight the need to carefully interrogate the data used in the models that underlie proposals for change; for example, recent work on the carbon footprint of pMDIs show this to be lower than that quoted in official documents [8]. The idea of combining pMDI with spacer as an emergency pack is evidence-based, since the effectiveness of the components of this therapeutic approach in exacerbations of asthma has been shown [9]. This could usefully form part of the self-management options for patients with asthma, regardless of the inhaler type used for routine therapy.

We acknowledge that our table should have included consideration of a low global warming potential device as one element in a carefully controlled approach to reducing the environmental impact of respiratory treatments. However, interpreting this as a switch to the DPI device class is wrong. When a change in treatment is being considered, healthcare professionals should consider “low global warming potential” (GWP) devices that include low-GWP pMDIs, DPIs and soft mist inhalers. Indeed, within 5 years, we will have clinically available pMDIs with potentially lower GWP than current DPIs [8]. It is vital, both in the UK context and internationally, that patients with asthma and COPD who need pMDIs retain access to them.

In the UK, as elsewhere, healthcare systems are currently operating under the massive additional stress of the coronavirus disease 2019 pandemic. Any change in the pattern of inhaler use should be deferred until a more normal service can be resumed, and none of our respiratory patients should be forced into switching inhalers. We must redouble our efforts to improve the education of health care professionals and patients in the use of inhaler devices. For sure, the greenest inhaler is an appropriately prescribed device, that the patient has been properly taught and assessed how to use, is happy with and most important of all, gives them clinical benefit [10].

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