Drivers of disparities in asthma exacerbation and healthcare utilization: a quantitative analysis of neighborhood deprivation in Southern California, United States

Objective While prior studies showed lower socioeconomic status was associated with worse acute asthma exacerbations (AAE) and asthma-related emergency department/urgent care (ED/UC) visits, few have quantified contributions of risk factors. We aim to identify and quantify risk factors driving these disparities across levels of neighborhood deprivation. Methods We conducted a cohort study of 79,562 adults with mild asthma in Kaiser Permanente Southern California, United States, during 2013–2018, with follow-up through 2019, comparing participants in Neighborhood Deprivation Index (NDI) quintiles five (Q5, most deprived) and one (Q1, least deprived). Outcomes included AAE and asthma-related ED/UC visits. We employed Oaxaca-Blinder decomposition to quantify contributions of 14 risk factors to these disparities. Results Individuals in NDI Q5 had a 1.5% higher rate of AAE and a 3% higher rate of ED/UC visits than those in Q1. The 14 risk factors explained 61.2% of the AAE disparity and 52.3% of the ED/UC disparity. Race and ethnicity contributed most, 33.1% of the AAE disparity and 22.8% of the ED/UC disparity, followed by body mass index, prior asthma exacerbations, and exercise levels. Conclusions These results underscore the need for targeted interventions addressing socioeconomic and behavioral factors to reduce asthma-related health disparities, particularly in disadvantaged populations.