Published Online: December 13, 2013
Anaphylaxis is a rapid-onset, potentially life-threatening systemic allergic reaction that can affect people of any age or sex. Current guidelines endorse aggressive therapy reflecting the possibility that any episode of anaphylaxis has the potential to cause death. However, the actual risk of death is unclear.
In a recent article published in The Journal of Allergy & Clinical Immunology (JACI), Ma et al. examined the fatality rate among hospitalization or emergency department (ED) presentations for anaphylaxis and the mortality rate associated with anaphylaxis for the general population. This was a population-based epidemiologic study using 3 national databases: Nationwide Inpatient Sample (NIS, 1999-2009), Nationwide ED Sample (NEDS, 2006-2009), and Multiple Cause of Death Data (MCDD, 1999-2009). Sources for these databases were hospital, ED discharge records and death certificates, respectively.
The authors found that case fatality rates were between 0.25% and 0.33% among hospitalizations or ED presentations with anaphylaxis as the principal diagnosis. These rates represent a total of between 63 and 99 deaths per year in the US, ~77% of which occurred in hospitalized patients. Rate of anaphylaxis hospitalizations rose from 21.0 to 25.1 per million population between 1999 and 2009. However, overall mortality rates appeared stable in the last decade and ranged from 0.63 to 0.76 per million population (186 to 225 deaths per year).
These results suggest that the overwhelming majority of hospitalizations or ED presentations for anaphylaxis did not result in death, with an average case fatality rate of 0.3%. Nationwide, despite the increase of anaphylaxis incidence, it is also reassuring that mortality rates associated with anaphylaxis have remained stable in the last decade and were well under 1 per million person-years. Both these observations likely reflect the quality of care that can be provided in the urgent care setting. Although anaphylactic reactions are potentially life threatening, the probability of dying is very low, especially for those cases that involve ED or hospital attention.
The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.