Equity in the provision of helicopter emergency medical services in the United Kingdom: a geospatial analysis using indices of multiple deprivation

Background Helicopter Emergency Medical Services (HEMS) in the United Kingdom (UK) are provided in a mixed funding model, with the majority of services funded by charities alongside a small number of government-funded operations. More socially-deprived communities are known to have greater need for critical care, such as that provided by HEMS in the UK. Equity of access is an important pillar of medical care, describing how resource should be allocated on the basis of need; a concept that is particularly relevant to resource-intensive services such as HEMS. However, the Inverse Care Law describes the tendency of healthcare provision to vary inversely with population need, where healthcare resource does not meet the expected needs in areas of higher deprivation. It is not known to what extent the Inverse Care Law applies to HEMS in the UK. Methods Modelled service areas were created with each small unit geography locus in the UK assigned to its closest HEMS operational base. The total population, median decile on index of multiple deprivation, and geographic area for each modelled service area was determined from the most recently available national statistics. Linear regression was used to determine the association between social deprivation, geographic area, and total population served for each modelled service area. Results The provision of HEMS in the UK varied inversely to expected population need; with HEMS operations in more affluent areas serving smaller populations. The model estimated that population decreases by 18% (95% confidence interval 1–32%) for each more affluent point in median decile of index of multiple deprivation. There was no significant association between geographic area and total population served. Conclusion The provision of HEMS in the UK is consistent with the Inverse Care Law. HEMS operations in more deprived areas serve larger populations, thus providing a healthcare resource inversely proportional with the expected needs of these communities. Funding structures may explain this variation as charities are more highly concentrated in more affluent areas.