INVESTIGATING THE USE OF THE SOCIAL VULNERABILITY INDEX TO PREDICT HEALTHCARE UTILIZATION AMONG PATIENTS WITH INFLAMMATORY BOWEL DISEASE
Authors: Dang Nhu , Cradeur Michael , Zeven Katherine , Khunte Mihir , Kumar Soryan , Marino Daniel , Kwon Michelle , Kamp Kendra , Oberai Ridhima , van Deen Welmoed , Tse Chung Sang , Melmed Gil , Siegel Corey , Weaver Alandra , Shah Samir 
Published: January 2023

Abstract

BACKGROUND
Social factors such as race, education, and financial hardships have been shown to affect health outcomes of patients with inflammatory bowel disease (IBD). Although early identification of socially vulnerable patients is critical for targeted interventions, it is still limited by screening tools that are incomprehensive and time-consuming. We investigate the utility of the social vulnerability index (SVI), a census tract-specific measure estimated by the Centers for Disease Control and Prevention, for predicting patients' healthcare utilization, based on 15 different social determinant variables including employment, housing, and transportation.

METHODS
We reviewed the electronic health records and surveys of patients with IBD at a private community practice enrolled in IBD Qorus Learning Health System, a national quality improvement consortium, from 2016-2021. Each patient's home address was mapped to an SVI value, ranging from 0 to 1 and increasing as the patient's vulnerability increased. An SVI was considered low if it was less than the median SVI and high if it was greater than or equal to the median SVI. Cox proportional hazards regression was performed to determine the relationship between SVI and healthcare utilization (IBD-related ED visit/hospitalization, urgent message*, and CT scan use), controlling for potential confounders such as IBD subtype, baseline clinical disease activity, physician global assessment, steroid use, and six-months-prior IBD-related ED visit/hospitalization and CT scan use. The “survival time” was defined as the time from when the patient first joined the program to IBD-related healthcare utilization events, loss of follow-up in the electronic health records, or the end of the study period, whichever occurred earliest.

RESULTS
Among 280 eligible patients, the median SVI was 0.288 (IQR 0.121-0.433) (Figure 1). Among the low SVI group, 16.4% experienced an IBD-related ED visit/hospitalization, 20.0% sent an urgent message, and 10.0% received a CT scan. Among the high SVI group, 23.6% experienced an IBD-related ED visit/hospitalization, 26.4% sent an urgent message, and 12.9% received a CT scan. High and low SVI groups (reference) were not significantly different in their healthcare utilization: ED visit/hospitalization (HR 1.66 [95% CI 0.96-2.89]), sending an urgent message (HR 1.62 [95% CI 0.94-2.70]), and CT scan use (HR 2.31 [95% CI 0.98-5.47]), after adjusting for confounders (Table 1).

CONCLUSION
IBD-related healthcare utilization was not associated with social vulnerability at the census tract level in this cohort. The lack of statistical significance was likely due to the cohort’s low sample size and lack of demographic variability (92% white and 96.8% non-Hispanic). Additional research with a larger and more diverse sample may help clarify the association between SVI and outcomes.