Comparing Paper Letters in Addition to Emailed Audit and Feedback in Refining Asthma Treatment to Improve Clinical and Environmental Results in Primary Care

A small collection of drug categories used by the health service produce a disproportionate amount of the total NHS greenhouse gas production, namely respiratory inhalers and anaesthetic gases (3% and 2% of total NHS production respectively). Inhalers are the mainstay of treatment for a variety of chronic respiratory conditions, offering a unique mechanism of drug delivery directly to the lungs to maximise effect and limit systemic side-effects. Four main inhaler device categories exist, including the pressurised Metered Dose Inhaler (pMDI - developed in the 1950s), the Dry Powder Inhaler (DPI - developed in the 1980s), the Breath-Actuated metered dose Inhaler (BAI), and the Soft Mist Inhaler (SMI - developed in the 2000s - currently only available to provide a long-acting muscarinic receptor antagonist). Since the 1990s, the pMDIs have been powered through hydrofluorocarbons (HFCs) - a greenhouse gas calculated to be 3800 times more powerful than that of carbon dioxide. This chemical propellant found in BAIs and pMDIs - rather than the medication itself - is the majority cause of the high carbon footprint related to all inhaler therapy, with pMDIs having an 18 times higher carbon footprint than DPIs.

There are no clear national guidelines on the clinical decision-making process of choosing between a pMDI or a DPI. To operate a DPI, there is a minimal Peak Expiratory Flow Rate (PEFR) required of between 20-50 L/min to overcome the device's internal resistance, with optimal PERF being between 40-65 L /min; this is often described as requiring a quick, deep breath creating turbulent flow to aid drug delivery (26). For a pMDI, a slow breath generating a PERF of around 30 L/min is optimal. A small study of healthy children found that while 100% of children age 5 could use a DPI with a flow rate of 30 L/min, only 62.5% could use one requiring 60 L/min; these numbers increased to 100% and 91.7% respectively for children aged 6. NICE recommended in 2000 that DPIs should be avoided for children under the age of 5. A literature review of inhaler technique studies highlighted that pMDIs require skilled coordination between actuation and inhalation for optimal drug delivery, which is not the case with DPIs. This review indicates that patients who struggle with pMDI coordination are often children and elderly patients, and they suggest that better technique is often achieved where one inhaler device type alone is used in a patient's care.

Although a pMDI may be preferred to a DPI in some clinical scenarios, England has a disproportionately high usage of pMDIs compared to its European neighbours; pMDIs were shown to make up 71.6% of all prescribed inhalers in England, compared to <50% in the rest of Europe and between 10-30% in Scandinavia (31,32). Given these figures, work has been undertaken in England to explore the effect of switching from pMDIs to DPIs in asthma. A post-hoc analysis from the Salford Lung Study (2236 patients) showed that moving to a DPI from a pMDI-based maintenance therapy more than halved their associated carbon footprint. Patients moved to DPIs also experienced consistently superior clinical outcomes compared to their baseline care and the majority of patients opted to remain on the DPI after switching. A large survey of UK asthma patients identified that 65% were unaware of the environmental impacts of pMDIs, with 60% of pMDI patients being open to switching their device type.

As previously stated, England has a significantly higher burden of disease from asthma compared with many other comparable countries, with that burden falling unequally on society in patterns determined by typical social determinants of health such as socioeconomic status. With two thirds of asthma deaths being linked to preventable factors, there is scope in this region to make significant health gains for the population whilst taking major strides to decrease health inequalities. The RCP report into asthma deaths produced a number of key recommendations for medical and professional care, signifying that all asthma patients should: be provided with a personal asthma action plan (PAAP); have a structured asthma review with an assessment of inhaler technique at least annually; be assessed for evidence of overuse of short-acting reliever and those that do should be invited for urgent review; be monitored for poor adherence to preventer inhaled corticosteroids; and be encouraged to use combination inhalers. There is notable overlay between the goals of improving asthma outcomes and improving the environmental impacts of asthma therapy, with both having a focus on using the right type of inhaler for the right patient and ensuring patients use effective inhaler techniques that optimises drug delivery whilst minimises waste.

Audit and feedback (A&F) is defined by Ivers et al. as the "provi(sion of) a recipient with a summary of their performance over a specified period of time" and has long history of use within a diverse area of research and business to promote clinician and organisational behaviour change. In healthcare, A&F has been used either alone, or as part of a composite quality improvement project (QIP), to improve health practitioner practice on the basis of guidelines or targets. A 2012 Cochrane review systematically reviewed 140 papers on A&F spanning several decades and produced a meta-analysis showing an absolute risk difference (RD) in practitioners changing behaviour to comply with preferred practice of 4.3% (interquartile range 0.5% to 16%). Their investigation emphasised that A&F is particularly effective when it is targeted specifically at prescribing practices (mean adj. RD 13.1% verses diabetes management 0.5%) and where baseline compliance is low. The authors hypothesised that this is because prescribing is a less complex behaviour that may be perceived by health practitioners as important. Meta-regression of the Cochrane data showed that the effect size of A&F has remained largely unchanged over the last two decades of study, leading the authors to postulate that there is no longer reasonable clinical equipoise to question if A&F is effective. However, they also conclude that studies aiming to isolate how A&F can be utilised most effectively by comparing different A&F variations are few and far between and that this should be the target of future A&F research. From the few studies that do exist comparing types of A&F, the meta-analysis showed that it is most effective when: a supervisor or respected colleague delivers the feedback; feedback is frequently presented; there are both specific goals and action-plans; focuses on decreasing a behaviour; there is low baseline performance; and when non-physicians are the focus of intervention.