Spatial access to Emergency General Surgery (EGS) services and EGS bypass behaviours in California.

Hospital bypass behaviours (i.e. people go to faraway hospitals instead of close ones) of Emergency General Surgery (EGS) patients may cause treatment delays and worsened health outcomes. This study aimed to find the associations between EGS bypass behaviours and spatial access to EGS services as well as other factors at the individual level and ZIP Code Tabulation Area (ZCTA) level in California. We used a gravity model to calculate spatial access to EGS services at the ZCTA level. A Bayesian hierarchical spatial model was used to access associated variables of EGS bypass while accounting for spatial autocorrelation. Results show that better spatial access to EGS hospitals was associated with lower likelihood of EGS bypass. Other factors such as rural-urban status, health insurance type and race/ethnicity were also related to EGS bypass behaviours. Besides, people with similar EGS bypass behaviours seemed to cluster together due to spatial effect. Our results have important implications for EGS resource allocation, utilization and EGS disparity alleviation.