OBJECTIVES: Potentially avoidable hospitalizations (PAH) are used as indirect measures of access to primary care. However, the evidence about the impact of primary care utilization on PAH is mixed. This study investigates the associations between PAH and measures of access and utilization of primary care in the French region Occitanie, while adjusting for socio-economic and epidemiologic determinants. We also highlight the importance of taking into account spatial autocorrelation and heterogeneity in ecological analyses of PAH.

METHODS: A retrospective analysis of claims and socio-economic data was performed for the French region Occitanie in 2014. The age- and sex-adjusted potentially avoidable hospitalization rates were modelled at the ZIP code level using spatial regression techniques.

RESULTS: The standardized rates of PAH vary from 1 to 14.6 per 1000 inhabitants at the ZIP code level; with a mean annual incidence of 4.85 cases per 1000 inhabitants. Congestive heart failure (47%) and chronic obstructive pulmonary disease (25%) were the most frequent categories of PAH. Results of our spatial models revealed the presence of spatial autocorrelation and spatial heterogeneity, which led to identifying two different zones in the Occitanie region based on socio-economic disparities. Separate spatial lag models were fitted in the two zones. Increased nurse density was associated to lower rates of PAH in both zones, but other primary care indicators differed in the two zones. Utilization of primary care had a more contrasted effect: at least one contact with general practitioners was associated with lower PAH rates in one zone, while increased number of contacts with specialist physicians and nurses were associated with higher PAH rates.

CONCLUSIONS: This study illustrates the importance of taking into account spatial heterogeneity when assessing and interpreting the role of primary care in geographic variations in PAH, by showing that PAH determinants might differ in different areas.