Automated Delineation of Hospital Service Areas and Hospital Referral Regions by Modularity Optimization.

<bold>Objective: </bold>To develop an automated, data-driven, and scale-flexible method to delineate hospital service areas (HSAs) and hospital referral regions (HRRs) that are up-to-date, representative of all patients, and have the optimal localization of hospital visits.<bold>Data Sources: </bold>The 2011 state inpatient database in Florida from the Healthcare Cost and Utilization Project.<bold>Study Design: </bold>A network optimization method was used to redefine HSAs and HRRs by maximizing patient-to-hospital flows within each HSA/HRR while minimizing flows between them. We first constructed as many HSAs/HRRs as existing Dartmouth units in Florida, and then compared the two by various metrics. Next, we sought to derive the optimal numbers and configurations of HSAs/HRRs that best reflect the modularity of hospitalization patterns in Florida.<bold>Principal Findings: </bold>The HSAs/HRRs by our method are favored over the Dartmouth units in balance of region size and market structure, shape, and most important, local hospitalization.<bold>Conclusions: </bold>The new method is automated, scale-flexible, and effective in capturing the natural structure of the health care system. It has great potential for applications in delineating other health care service areas or in larger geographic regions. [ABSTRACT FROM AUTHOR]