2026 FSA Podium and Poster Abstracts

Introduction/Background: Perioperative anaphylaxis is a rare but potentially life-threatening complication of anesthesia that can result in significant cardiovascular or respiratory compromise. Risk factors may include previous episodes of drug or food allergies and atopy. Patients with atopic conditions such as asthma and allergic rhinitis may be at increased risk due to immune dysregulation and altered inflammatory responses. Despite this plausibility, population-level data evaluating the identified rate and relative risk of perioperative anaphylaxis in these patients remain limited.

Methods: A retrospective cohort study was conducted using Epic Cosmos, a large deidentified electronic health record database representing multiple U.S. health systems. Anesthesia encounters were identified using billed procedure codes associated with anesthesia care. Encounters were stratified based on the presence or absence of physician-coded atopic conditions, defined by ICD-10 diagnosis codes for asthma and allergic rhinitis documented prior to or during the anesthesia encounter. Encounters without these diagnoses served as the comparison group. To focus on perioperative anaphylaxis identified within the database, the atopic cohort was restricted to anesthesia encounters without a documented history of anaphylaxis prior to the encounter, based on available diagnosis coding.

The primary outcome was physician-coded perioperative anaphylactic shock, identified using ICD-10 codes T78.2 (anaphylactic shock, unspecified) and T78.2XXA (anaphylactic shock, unspecified, initial encounter) recorded during encounters that included billed anesthesia procedures. Database-identified rates were calculated as the number of anaphylaxis cases per total anesthesia encounters. Relative risks were calculated by comparing encounters among patients with atopic conditions to those without atopic diagnoses. Demographic characteristics, including age, sex, and race, were summarized descriptively.

Results: Among 2,220,333 anesthesia encounters in patients with asthma captured in the database, 160 cases of perioperative anaphylaxis were identified. This corresponded to a database-identified rate of 0.0072% (7.2 per 100,000 encounters), compared with 0.0031% (3.1 per 100,000) in non-asthmatic patients (RR = 2.36). Among 143,140 anesthesia encounters in patients with allergic rhinitis, 17 cases of perioperative anaphylaxis were identified resulting in a database-identified rate of 0.0119% (11.9 per 100,000 encounters), compared with 0.0035% (3.5 per 100,000) in patients without allergic rhinitis (RR = 3.39). 

Discussion/Conclusion: In this large retrospective analysis within the Epic Cosmos database, anesthesia encounters involving patients with physician-documented asthma or allergic rhinitis demonstrated higher relative rates of perioperative anaphylaxis compared with encounters without these atopic diagnoses. Although allergic rhinitis is commonly viewed as a marker of atopic predisposition, the association observed in this dataset was more pronounced among encounters involving patients with asthma, which may reflect differences in disease severity, airway hyperresponsiveness, or differential clinical recognition and coding. Absolute event rates were low, and these findings represent database-identified rates rather than true population-level incidence. Therefore, the observed associations suggest that atopic conditions, particularly asthma, may represent clinically relevant risk factors warranting further investigation to refine perioperative risk stratification and anesthetic planning.