B40-02 Emergency-dependent Hospital Arrival Defines Distinct Immuno-physiologic Phenotypes In Covid-19 Hospitalizations

Background

Patients hospitalized with COVID-19 exhibit substantial heterogeneity in clinical severity and immune response. While mode of hospital arrival is often considered a surrogate for illness acuity, its relationship to underlying immuno-inflammatory profiles and clinical outcomes remains poorly characterized, particularly for early risk stratification. We sought to determine whether emergency-dependent arrival reflects distinct biologic phenotypes and independently predicts in-hospital mortality.

Methods

We conducted a retrospective cohort study of adults hospitalized with COVID-19. Hospital arrival was classified as emergency-dependent (ambulance or inter-facility transfer) or non-emergency (self-arrival). Demographics, race, physiologic severity (SOFA score), immune biomarkers including CD4 count, neutrophil-to-lymphocyte ratio (NLR), and interleukin-10 (IL-10), as well as oxygenation measured by PaO₂/FiO₂ ratio were collected. Continuous variables were summarized as median [IQR] and compared using non-parametric testing. Multivariable logistic regression was performed in patients with complete data to evaluate the independent association between emergency-dependent arrival and in-hospital mortality, adjusting for age, SOFA score, race, and immune biomarkers. Data analysis was performed using IBM SPSS Statistics 25.0.

Results

Among 994 hospitalized patients, emergency-dependent arrival was associated with older age and greater physiologic severity at presentation. Compared with patients who self-presented, emergency-dependent arrivals demonstrated lower CD4 counts, higher IL-10 levels, elevated NLR, and worse oxygenation, reflected by lower PaO₂/FiO₂ ratios (all p < 0.05). Emergency-dependent arrival occurred more frequently among Hispanic and African-American patients compared with Caucasian patients (p < 0.05). In multivariable analysis of 134 patients with complete data, emergency-dependent arrival was not independently associated with in-hospital mortality after adjustment for age, SOFA score, race, and immune biomarkers (adjusted OR 1.01, 95% CI 0.40-2.52, p = 0.99). Elevated NLR (adjusted OR 3.61, 95% CI 1.60-8.16, p = 0.002), higher IL-10 levels (adjusted OR 0.98 per unit increase, 95% CI 0.96-0.99, p = 0.01), and greater physiologic severity remained the strongest independent predictors of mortality.

Conclusions

Emergency-dependent hospital arrival identifies a distinct immuno-inflammatory and physiologic phenotype in patients hospitalized with COVID-19 but does not independently predict mortality after accounting for severity of illness and immune dysregulation. These findings suggest that arrival context may serve as an early clinical marker of underlying biologic vulnerability,potentially informing , early risk stratification and patient management.Integrating immunologic profiling with traditional severity assessment may improve early risk stratification in severe COVID-19.

This abstract is funded by: none