Temporal and geographical variation in low carbon inhaler dispensing in England, 2016 to 2021: an ecological study

OBJECTIVES: In 2019–2020, four national recommendations were published in the United Kingdom to encourage use of low carbon inhalers. This study aimed to investigate whether these were associated with a change in primary care dispensing in England and to explore associations between geographical variation and clinical commissioning group (CCG) characteristics. DESIGN: Ecological study using aggregated publicly available data. SETTING: All CCGs in England (March 2016 to February 2021). PARTICIPANTS: not applicable MAIN OUTCOME MEASURES: Percentage of low carbon inhalers dispensed. RESULTS: The percentage of low carbon inhalers dispensed was 26.3% in 2020–2021 (of 8.8 million inhalers). This decreased over the study period for short-acting beta-agonist (SABA), inhaled corticosteroid (ICS) and ICS+long-acting beta-agonist (LABA) inhalers. The same trend was seen for LABA and ICS+LABA+long-acting muscarinic antagonist inhalers from 2019. The SABA and ICS classes were less often dispensed as low carbon inhalers (⁓6% versus 35–45%). Interrupted time series analyses found slight increases in low carbon inhaler percentage in the SABA, LABA and ICS classes after April 2019, which were soon erased by the long-term trend. There was also geographical variation, with the north-west, Birmingham and London consistently dispensing more low carbon inhalers. The presence of advice on climate change in CCG formularies/guidelines, the prevalence of asthma and population age profile were associated with significant variation in low carbon inhaler percentage for some classes. CONCLUSIONS: The percentage of low carbon inhalers dispensed in England remains low and continues to decrease. Greater use of low carbon inhalers is achievable, but is more likely with locally implemented initiatives.