Food Anaphylaxis in the United Kingdom: Analysis of National Data, 1998–2018

Abstract

To analyze trends in hospital admissions for food anaphylaxis in the United Kingdom from 1998 to 2018, including case-fatality rates.All patients admitted to hospitals for anaphylaxis in the United Kingdom (England, Scotland, Wales, and Northern Ireland) were studied. Children were identified as age ≤15 years.International Classification of Diseases, 10th Revision, codes were analyzed for all allergy-related admissions with both food-related and non–food-related causes, by using the Hospital Episodes Statistics database via the National Health Services. Fatal food-induced anaphylaxis data has been recorded through the UK’s Fatal Anaphylaxis Registry. Admission data were compared along time trends among different age groups, sex, and inciting triggers. Trends in the national case-fatality rate and epinephrine autoinjector (EAI) prescriptions were also analyzed.Across all age groups, allergy-related hospital admissions increased during the study period from 10 to 28 admissions per 100 000 population per year, at a rate ratio of 1.043 (1.042 to 1.043; P < .001). A total of 255 913 admissions occurred during the 10-year interval, of which 39.8% were due to anaphylaxis. The rate of anaphylaxis-associated admissions increased by 179%, with a rate ratio of 1.047 (1.046 to 1.048; P < .001) and was similar across all age groups. Girls had a higher rate of admission for nonfood anaphylaxis admissions. Boys (age: <15) had a higher rate of admission with food triggers, but this predominance dissipated into adulthood. A total of 30.1% of admissions for anaphylaxis were identified with a food trigger, with an annual rate ratio of 1.057 (1.055 to 1.059; P < .001). The greatest increase was observed in children, from 2.1 to 9.2 admissions per 100 000 or an increase of 339%. Individuals aged 15 to 59 years had an increase of 214%, whereas those aged >60 years had an increase of 78% over the same time interval. Despite a national recommendation in 2016 encouraging admission for children with suspected anaphylaxis, the admission rate for children did not significantly increase. The annual fatality rates from food-induced anaphylaxis were 0.009 and 0.008 per 100c000 population in 1998 and 2018, respectively, but the case-fatality rate had decreased from 0.70% to 0.19% in the same period. The highest rate of fatalities occurred in teenagers. Children <5 years of age were more likely to be admitted for anaphylaxis but had lower rates of death. A total of 46% of fatalities were associated with peanuts or tree nuts. Additionally, the fatality rate associated with cow’s milk increased since 1992, with 26% of deaths in children and 5% in adults caused by cow’s milk exposure. The rates of death from peanuts and tree nuts decreased during this interval. Prescriptions for EAI devices increased by 336% overall or by an 11% increase on a year-by-year basis.From 1998–2018, the number of hospital admissions for anaphylaxis and prescriptions for EAIs in the United Kingdom significantly increased, and the case-fatality rate for anaphylaxis decreased. Peanuts and tree nuts accounted for the greatest portion of fatal reactions, but among children <5 years of age, cow’s milk was the most common trigger.The strengths of this study include the use of 20 years of data and a national database that examined >255 000 admissions. This study also revealed the increasing role of cow’s milk anaphylaxis in food allergy fatalities. This study relied on International Classification of Diseases, 10th Revision, codes. It is possible that the data regarding admissions and fatalities are an underestimate because anaphylaxis and its triggers are often not coded accurately.