Local variation in low carbon footprint inhalers in pre-COVID pandemic primary care prescribing guidelines for adult asthma in England and its potential impact

Abstract

Aims: Pressurised metered-dose inhalers (MDIs) have a much higher carbon footprint than dry powder inhalers (DPIs). We aimed to describe variations of inhaler options in local adult asthma prescribing guidance.

Methods: We reviewed local clinical commissioning group (CCG) adult asthma prescribing guidance for primary care in England in 2019 and recorded DPI and MDI inclusion. The relationship to prescribing data from OpenPrescribing.net was examined.

Results: In total, 58 unique guidance documents were analysed covering 144 out of 191 CCGs in England. Only 3% of CCG guidelines expressed an overall preference for DPIs, while 12% explicitly preferred MDIs. The inclusion of DPIs first-line was 77% for short-acting β-agonists, 78% for low-dose inhaled corticosteroid (ICS) inhalers and 90-96% for combination long-acting β-agonist/ICS inhalers. MDIs were included first-line in 98-100% of these classes. In 26% of CCGs, there was no first-line DPI option for at least 1 asthma management step. Ten percent of CCGs had no DPI included first-line for any of the 5 classes examined. Many CCGs recommended higher carbon footprint options; Ventolin MDI (25.6%), inhalers containing HFA227ea (57.9%) and ICS regimes recommending 2 puffs of a lower dose over 1 puff of higher dose (94.2%). MDIs were prescribed more in CCGs that recommended them.

Conclusion: Before the COVID pandemic, there was substantial variation between CCGs in adult asthma prescribing guidance regarding higher and lower carbon footprint options. There may still be scope to amend local guidance to improve clinical and environmental outcomes. This study provides a method and baseline for further investigation of this.

Keywords: asthma; climate change; prescribing; respiratory medicine.

FIGURE 1

Metered‐dose inhaler (MDI) prescription proportion by statement of explicit preference for inhaler type in guidance. Point estimate and distribution of MDI prescriptions (as a proportion of total inhaler prescribing) is shown for 3 groups of clinical commissioning groups (CCGs); those with no recommendation in their guidance, those that explicitly recommended dry powder inhalers (DPIs) overall and those that explicitly recommended MDIs overall. Prescription data include all indications for inhalers (including asthma and chronic obstructive pulmonary disease) but excludes salbutamol relievers. For each group, the blue box represents the interquartile range, the black bar shows the median value and the whiskers show 1.5× interquartile range outside of the first and third quartiles. Data points outside this range are shown as unfilled circles, each representing 1 CCG. On pairwise comparisons with the Bonferroni correction the only significant difference is between MDIs recommended and no recommendation (Kruskal–Wallis H = 9.02, 2), adjusted significance: P = .011). No significant difference was found between DPIs recommended and MDIs recommended or DPIs recommended and no recommendation (adjusted significance: P = .146, P > .999)

FIGURE 2

Metered‐dose inhalers (MDI) proportion by low‐dose inhaled corticosteroid (ICS) device recommendation in guidance. Point estimate and distribution MDI prescription proportion for 2 groups; clinical commissioning groups (CCGs) that did have dry powder inhalers (DPIs) containing a low‐dose ICS included first‐line, and those that did not. Prescription data include all indications for inhalers (including asthma and chronic obstructive pulmonary disease) but excludes salbutamol relievers. For each group, the blue box represents the interquartile range, the black bar shows the median value and the whiskers show 1.5× interquartile range outside of the first and third quartiles. Data points outside this range are shown as unfilled circles, each representing 1 CCG. The difference between the 2 groups was statistically significant (Mann–Whitney U = 1255, P = .016).

FIGURE 3

Metered‐dose inhaler (MDI) proportion by low‐dose combination device recommendation in guidance. Point estimate and distribution in MDI prescription proportion for 2 groups; clinical commissioning group (CCGs) that did have low‐dose combination dry powder inhalers (DPIs) included first‐line, and those that did not. Prescription data include all indications for inhalers (including asthma and chronic obstructive pulmonary disease) but excludes salbutamol relievers. For each group, the blue box represents the interquartile range, the black bar shows the median value and the whiskers show 1.5× interquartile range outside of the first and third quartiles. Data points outside this range are shown as unfilled circles, each representing 1 CCG. There was no significant difference between the 2 groups (Mann–Whitney U = 810, P = .42).

FIGURE 4 Flowchart of output of search for guidance documents as per method in Appendix 1. CCG, clinical commissioning group; MDI, metered‐dose inhaler; DPI, dry powder inhaler