Retrospective Study of Drug-induced Anaphylaxis Treated in the Emergency Department or Hospital: Patient Characteristics, Management, and 1-Year Follow-up

Abstract

Drugs are a common cause of anaphylaxis, which is potentially life threatening. We sought to describe US patients with an emergency department (ED) visit or hospitalization for drug-induced anaphylaxis (DIA), including postdischarge follow-up care. By using International Classification of Diseases, Ninth Revision codes in the MarketScan Database, we identified all patients with an ED visit and/or hospitalization for DIA between 2002 and 2008 (index date = initial ED visit and/or hospitalization). Inclusion required continuous full insurance coverage ≥1 year in the pre- and postindex period. We examined patient factors during the preindex period, characteristics of the index event, and outcomes during the postindex period. The cohort included 716 patients with an ED visit and/or hospitalization for DIA (mean age, 48 years; 71% women). Most patients (71%) were managed in the ED, and only 8% of the patients with DIA treated in the ED received epinephrine. For those admitted, patients were hospitalized for a median of 3 days, and 41% spent time in the intensive care unit. Cardiorespiratory failure occurred in 5% of the patients in the ED and 23% of the patients who were hospitalized. The patients with a concomitant allergic condition were more likely to see an allergist/immunologist than those without a concomitant allergic condition, but 82% did not receive any subsequent care with an allergist/immunologist in the 1 year after the ED visit and/or hospitalization for DIA. Drugs are a common, yet under-recognized, cause of anaphylaxis. Only a small number of patients with DIA received epinephrine in the ED or had subsequent care with an allergist/immunologist. These findings are novel and identify areas for improvement in the care of individuals with DIA.