Prevalence of food allergy increased 1.7 times in the past 10 years among Japanese patients below 6 years of age.

BACKGROUND: While food allergy (FA) has been increasingly recognized as a growing public health burden worldwide, epidemiological studies on FA in Japan are limited.

METHODS: This was a noninterventional, observational study using the administrative claims data from 2010 to 2019 (10 years). Patients with physician-diagnosed FA in Japan (prevalent cohort) were divided into high-risk or low-risk cohorts using adrenaline prescription. The high-risk cohort was further divided into anaphylaxis or nonanaphylaxis cohort based on the occurrence of anaphylaxis or a serious allergic reaction (SAR) during 1 year after adrenaline prescription. The primary objective was to examine yearly prevalence of FA. The secondary objectives were to describe demographics/clinical characteristics and healthcare resource utilization (HCRU), to evaluate the number of occurrences of anaphylaxis/SAR in the high-risk cohort, and the impact of anaphylaxis/SAR on HCRU.

RESULTS: The overall standardized prevalence rate was 0.325% (95% confidence interval [CI], 0.311-0.339) in 2010 and 0.797% (95% CI, 0.790-0.804) in 2019 and predominant in patients age <6 years (preschool; 3.377% [95% CI, 3.229-3.525] in 2010 and 5.726% [95% CI, 5.663-5.789] in 2019). Majority of FA patients (>80%) were children/adolescent throughout the 10 years. While high-risk cohort was a relatively minor population (8.5% in the prevalent cohort in 2019), the occurrence of anaphylaxis/SAR in the high-risk cohort was 227,690/100,000 patient-years. Multivariate analysis showed a significant increase in HCRU variables in the anaphylaxis versus nonanaphylaxis cohort (e.g., 2.08 [95% CI, 2.05-2.11] times more FA-related outpatient visits).

CONCLUSIONS: Prevalence of FA increased in a statistically significant way from 2010 to 2019; 1.7-fold increase was observed in patients <6 years old. Patients in the high-risk cohort appear to have suffered from frequent anaphylaxis/SAR, highlighting an unmet medical need for FA patients at "high-risk," considering the unavailability of approved medications to prevent anaphylaxis/SAR.