Using OpenPrescribing.net to evaluate neighbourhood-level prescribing of inhalers for asthma and COPD

Prescribing of inhalers for asthma and chronic obstructive pulmonary disease is complicated due to multiple treatment pathways, diverse products, and variability in patients' needs and usage habits. Factors such as social deprivation, air quality, and differences in access to primary care influence both demand on respiratory medications and the rate and manner in which they are prescribed. Inhaler prescribing metrics are valuable for analysing temporal and geographic prescribing patterns across socio-economic groups, whether to identify areas with higher disease incidence or to assess problematic prescribing practices. Using data from OpenPrescribing.net, we estimate prescription items dispensed for different inhaler drugs in England at Lower Layer Super Output Area or 'neighbourhood' level. Generating metrics at small-area level enables analysis of the interactions between individuals, their environment, and the localised health system within which they are being treated. This approach complements a patient-centred clinical model that considers individual patient needs. To explore changes pre- and post- the March 2020 COVID-19 lockdown, we profile prescribing temporally and by neighbourhood-level deprivation, measured by the Index of Multiple Deprivation. We develop and apply seven prescribing measures informed by national clinical guidelines which facilitate contextual comparison of prescribing behaviour between neighbourhoods. We find inequalities in prescribing behaviour, with the most deprived neighbourhoods associated with higher rates of emergency or 'rescue' inhaler prescribing - a pattern that was interrupted during the March 2020 lockdown. Additionally, we find an increase in the prescribing of less environmentally friendly inhalers, contrary to national prescribing guidelines. This trend persisted until early 2022, when the trend began to reverse. Whilst many complex factors influence prescribing behaviour and safety, area-level deprivation appears to be an important dimension.