Background: Sepsis severity of illness is challenging to measure using claims, which makes sepsis difficult to study using administrative data. We hypothesized that emergency department (ED) charges may be associated with hospital mortality, and could be a surrogate marker of severity of illness for research purposes. The objective of this study was to measure concordance between ED charges and mortality in admitted patients with severe sepsis or septic shock.
Methods: Cohort study of all adult patients presenting to a 60,000-visit Midwestern academic ED with severe sepsis or septic shock (by ICD-9 codes) between July 1, 2008 and June 30, 2010. Data on demographics, admission APACHE-II score, and disposition was extracted from the medical record, and comorbidities were identified from diagnosis codes using the Elixhauser methodology. Summary statistics were reported and bivariate concordance was tested using Pearson correlation. Logistic regression models for 28-day mortality were developed to measure the independent association with mortality.
Results: We included a total of 294 patients in the analysis. We found that ED charges were inversely related to mortality (adjusted OR 0.829 per $1000 increase in total ED charges, 95%CI 0.702-0.980). ED charges were also independently associated with 28-day hospital-free and ICU-free days (0.74 days increase per $1000 additional ED charges, 95%CI 0.06-1.41 and 0.81 days increase per $1000 additional ED charges, 95%CI 0.05-1.56, respectively). ED charges were also associated with APACHE-II score ($34 total ED charges per point increase in APACHE-II score, 95%CI $6-62).
Conclusions: ED charges in administrative data sets are associated with in-hospital mortality and health care utilization, likely related to both illness severity and intensity of early sepsis resuscitation. ED charges may have a role in risk adjustment models using administrative data for acute care research.
Keywords: Costs and cost analysis; Critical illness; Emergency service, hospital; Health services research; Risk adjustment; Sepsis.