Recent trends in anaphylaxis-related hospitalization in the United States
Objectives Anaphylaxis is a severe, often life-threatening, allergic reaction (commonly to foods, insect stings, and medications), frequently requiring immediate medical attention. This study examined recent trends of anaphylaxis-related hospitalization in the United States (US). Methods Study data were drawn from the Healthcare Cost and Utilization Project’s 2001-2012 National (Nationwide) Inpatient Samples (NIS), a nationally representative database of hospital discharges in the US. Anaphylaxis-related hospitalizations were identified using a modification of a previously published algorithm (Walsh et al, 2013); this algorithm evaluates diagnosis codes on each record to identify anaphylaxis-related hospitalizations. In addition to quantifying the rate of hospitalization (per 100,000 US population), length of stay (LOS) and total costs for such hospitalizations were evaluated. Overall estimates, as well as by age group, were generated. Results Across all age groups, the rate of anaphylaxis-related hospitalizations increased by ~62% between 2001 and 2012, from 2.4/100,000 US population in 2001 to 3.8/100,000 in 2012. In general, annually the greatest rate was among those 65-84 years old, although the greatest rate observed was for those 85+ years in 2012, at 8.0/100,000, with rates among this age group steadily increasing over time. Among all anaphylaxis-related hospitalizations, the mean total cost (in 2014 US dollars) increased by more than 55%, from $12,508 in 2001 to $19,420 in 2012. The mean LOS across all anaphylaxis-related hospitalizations increased by >1 full day, from 3.7 days in 2001 to 4.9 days in 2012. Conclusions Since the early 2000s, rates of anaphylaxis-related hospitalization in the US have increased, with the mean LOS and cost per stay increasing as well. Healthcare decision makers should be aware of these data as they plan for allocation of resources used to treat anaphylaxis.