Epidemiology and trends of anaphylaxis in the United States, 2004-2016

Background: No national study has examined the epidemiology of anaphylaxis after introduction of the codes of the International Statistical Classification of Diseases and Health Related Problems, Tenth Revision, Clinical Modification (ICD-10 CM). Our objective was to examine the trends in incidence and hospitalization rates in the United States utilizing ICD-9 and ICD-10 CM codes. Methods: We used the Clinformatics database from 2004 to 2016. Our outcome measures included incidence of anaphylaxis and hospitalization trends. Multivariable logistic regression was used to assess the predictors of anaphylaxis and hospitalization. Results: There were a total of 462,906 anaphylaxis cases. The incidence increased from 153 in 2004 to 218 in 2016 (per 100,000). Women were 1.19 (95% confidence interval, 1.18-1.20) times more likely to present with anaphylaxis. Medication-induced anaphylaxis increased 15-fold. Conclusion: This is the first population-based study that included ICD-10 CM codes to describe the epidemiology of anaphylaxis in the United States. ICD-10 codes improved the accuracy of medication-induced anaphylaxis, the most likely etiology to result in hospitalization.