Increase in anaphylaxis-related hospitalizations but no increase in fatalities: an analysis of United Kingdom national anaphylaxis data, 1992-2012

Abstract

Background: The incidence of anaphylaxis might be increasing. Data for fatal anaphylaxis are limited because of the rarity of this outcome.

Objective: We sought to document trends in anaphylaxis admissions and fatalities by age, sex, and cause in England and Wales over a 20-year period.

Methods: We extracted data from national databases that record hospital admissions and fatalities caused by anaphylaxis in England and Wales (1992-2012) and crosschecked fatalities against a prospective fatal anaphylaxis registry. We examined time trends and age distribution for fatal anaphylaxis caused by food, drugs, and insect stings.

Results: Hospital admissions from all-cause anaphylaxis increased by 615% over the time period studied, but annual fatality rates remained stable at 0.047 cases (95% CI, 0.042-0.052 cases) per 100,000 population. Admission and fatality rates for drug- and insect sting-induced anaphylaxis were highest in the group aged 60 years and older. In contrast, admissions because of food-triggered anaphylaxis were most common in young people, with a marked peak in the incidence of fatal food reactions during the second and third decades of life. These findings are not explained by age-related differences in rates of hospitalization.

Conclusions: Hospitalizations for anaphylaxis increased between 1992 and 2012, but the incidence of fatal anaphylaxis did not. This might be due to increasing awareness of the diagnosis, shifting patterns of behavior in patients and health care providers, or both. The age distribution of fatal anaphylaxis varies significantly according to the nature of the eliciting agent, which suggests a specific vulnerability to severe outcomes from food-induced allergic reactions in the second and third decades.

Keywords: Anaphylaxis; drug allergy; epidemiology; food allergy; hospitalization; insect sting allergy.

Fig E1

Distribution of hospital admissions (A) and fatalities (B) caused by food-induced anaphylaxis by age and sex.

Fig 1

Time trends in hospital admissions (A) and fatalities (B) for all-cause anaphylaxis between 1992 and 2012. Vertical bars represent SEMs.

Fig 2

Age distribution of ASRs for admissions (1998-2012; A) and fatalities (1992-2012; B) caused by anaphylaxis by triggering agent (food, iatrogenic causes, and insect stings).

Fig 3

Time trend in ASRs for admissions to hospital with anaphylaxis (A, C, and E) and fatalities (B, D, and F) by trigger: food, iatrogenic causes, and insect stings. Vertical bars represent SEMs.

Fig 4

Cause of fatal food-induced anaphylaxis cases by trigger in children (A) and adults (B) and by 5-year groups (C).

Fig 5

Incidence of fatal anaphylaxis expressed as a proportion of hospital admissions caused by anaphylaxis by trigger.

Fig 6

Prescription of epinephrine autoinjectors to English residents from 1998 to 2012.