P2.091: The Cost of Inequality: Neighborhood-Level Social Vulnerability and Pediatric Asthma Emergency Department Visits

Background: Social determinants of health affect health outcomes, including those of asthma, despite advancements in prevention and treatment of exacerbations. The Social Vulnerability Index (SVI) [Figure 1], a measure of the social determinants of health of an area, influences multiple health outcomes but there is paucity of data on how SVI affects asthma exacerbation rates. We investigated the impact of neighborhood-level SVI on the age-adjusted asthma-related emergency department visit (AAAED) rates in California in 2022. We hypothesized that children with asthma who lived in zip codes with high SVI will have higher AAAED rates compared to those in zip codes with lower SVI.

Methods: We performed a retrospective cohort study by linking AAAED rate in each zip code in California to the corresponding SVI data obtained from the Agency for Toxic Substance and Disease Registry (ATSDR). We examined all children aged between 0-17 years in California with an asthma ED-related visit in the year 2022. Children older than 17, non-California residents and zip codes with no recorded AAAED rate or SVI data were excluded. SVI values for zip codes were assigned percentiles scores from 0-1 with higher percentiles corresponding to greater social vulnerability. SVI rankings were then divided into quartiles (first quartile: SVI-Q1: 0-0.25, least vulnerable and 0.75-1 as SVI-Q4, most vulnerable). The exposure was SVI quartile, and the outcome was the difference in AAAED rate between zip codes in SVI-Q4 and SVI-Q1. The AAAED rate, adjusted for sex, age, and poverty level, was calculated and expressed as per 10,000 children with 95% CI intervals CI). A negative impact by SVI was signified by a higher AAAED rate in SVI-Q4 compared to SVI-Q1 and non-overlapping 95% CIs. Rate ratio (RR) and associated CIs were estimated by comparing the AAAED rate between SVI-Q4 and SVI-Q1 using negative binomial regression. RRs with 95% CI that did not cross 1 defined statistical significance.

Results: In 2022, 46,445 pediatric asthma-related ED visits occurred in 870 zip codes in California. The distribution of zip codes per SVI quartile were: SVI-Q1 10.3%, SVI-Q2 22.6% and SVI-Q3 26.7%, and SVI-Q4 40.3%. As shown in Fig 1, there was a stepwise increase in the geometric mean of AAAED rate 32.8 (CI: 30.3 – 35.2) in SVI-Q1 to 65.1 (CI: 62.5 – 67.6) in SVI-Q4 (Figure 1). Compared to SVI-Q1, zip codes in SVI-Q4 had an excess of 32.3 asthma-related ED visits. Compared to SVI-Q1, SVI-Q3 and SVI-Q4, had increased rate ratios of 1.7 (CI: 1.3 – 2.1) and 3.0 (CI: 2.4 – 3.9),respectively.

Conclusion: Zip codes with higher SVI were associated with higher asthma-related ED visits in California. This can inform resource allocation and investment aimed at improving asthma outcomes by addressing social determinants of health in areas with higher social vulnerability.