Using the Social Vulnerability Index to Examine Local Disparities in Emergent and Elective Cholecystectomy

Background: The Social Vulnerability Index (SVI) is a composite scale formulated by the Centers for Disease Control and is geocoded as a percentile ranking at the census tract level. SVI is potentially applicable to assess risk and target populations that are likely to present emergently for disease that could have been treated electively and target local disparities. We applied the SVI to compare cholecystectomy patients presenting emergently versus electively. Methods: We identified patients who had undergone cholecystectomy at our academic medical center over a 6-month period. We abstracted patient demographics, chronic symptom duration, and diagnosis from the medical record. Patient addresses were geocoded to identify their census tract of residence and estimated SVI. Results: Two hundred and fifty five patients met inclusion criteria. Most patients (n = 185, 72.5%) had surgery in the emergent setting. Emergent patients lived in areas of greater social vulnerability compared with elective patients (median SVI 75th versus 64th percentile, P < 0.001). On multivariable analysis adjusting for chronicity of symptoms and patient proximity to the hospital, having high SVI (>70th percentile) was associated with higher odds of undergoing an emergent versus an elective procedure (OR 2.05, P = 0.04). Conclusions: The SVI has potential utility for examining health care disparities, performing comparably with a more complex model including individual risk factors. Because it is a composite measure geocoded at the census tract level for all communities in the United States, it has potential for targeting relatively discrete geographic areas for intervention. Being a geocoded measure also offers opportunity for linking with other data sets using geographic information systems.