3 questions to… Véronique Lucas-Gabrielli and Catherine Mangeney following the publication of the Issues in Health Economics (246), January 2020: "How can the Methods for Measuring the Spatial Inequalities of Access to General Practitioners be Improved? Illustration in Ile-de-France"
Research on spatial inequalities in access to primary care uses "floating density" type indicators or Two-step Floating Catchment Area (2SFCA) type to enrich the measurements obtained from density or distance calculations alone. Adapted to the French context, the Local Potential Accessibility (LPA) applied to general practitioners makes it possible to reconsider the observations previously made in this area by proposing a better quantification of the healthcare supply and needs and an adjusted understanding of the interaction between healthcare supply and demand.
To further improve the measurement, we are developing this indicator in several ways: by reducing the geographical scale of observation, from the municipality to the 200 x 200m grid; by taking into account the social dimension of needs and differentiated mobility practices (car, public transport, etc.); by proposing a new approach to the spatial interactions between healthcare supply and demand which makes it possible to assess real behaviours in the consultation of GPs by considering that if healthcare services are available within close proximity, patients tend to travel less further and inversely; finally, by taking into account the specialist care supply.
By taking the Ile-de-France region as a framework for analysis, we show that the change in the geographical scale of observation highlights situations that are sometimes highly contrasted between different districts in the same municipality. The new approach to spatial interactions between healthcare supply and demand is another evolution that greatly modifies the measured levels of accessibility, adjusting their spatial representation by rebalancing the situations between neighbouring grids. The integration of the social dimension of mobility needs and practices (car, public transport) has more local impacts. For example, weighting populations according to age increases care needs in the departments of Paris and Hauts-de-Seine, mainly, while the introduction of the social dimension of care needs has a particularly marked effect in Seine-Saint-Denis. Putting the indicator into a more global context, in particular by taking into account the alternative medical supply of primary care specialists, leads to a very significantly modified vision of the infra-regional balances.
The results’ sensitivity to the different hypotheses tested and presented in this study on the basis of scenarios, pleads in favour of completing the observations made in terms of spatial accessibility. The development of this type of indicator shows, therefore, the importance of mobilising both phases of statistical calculation and geographical representation of the results on different scales, and also of interchanging with institutional or local partners. These exchanges make it possible to refine and validate the hypotheses adopted by comparing them to the perception of the stakeholders - users, health professionals and decision-makers - who live and work in a given region, but also to take into account the specificities of certain regions.