Abstract
BACKGROUND: Understanding the trends of anaphylaxis and risk factors associated with its recurrence is essential for the effective management and prevention of this condition. OBJECTIVE: This study aimed to analyze the prevalence trends of anaphylaxis and identify risk factors for recurrence, with a focus on the influence of neighborhood deprivation and comorbidities, across all age groups. METHODS: We conducted a retrospective administrative cohort study on anaphylaxis utilizing the National Health Insurance-National Sample Cohort (NHIS-NSC) database in Korea (2002-2019). Anaphylaxis was defined with ICD-10 codes for the diagnosis combined with prescription codes. The Neighborhood Deprivation Index was used to identify the risk of recurrent anaphylaxis. Trends in the annual prevalence and recurrence of anaphylaxis were assessed through joinpoint regression and Cox proportional hazard models. RESULTS: Out of the 1,137,861 individuals studied, 37,012 (3.25%) cases of anaphylaxis were identified. Among these, 5783 individuals (15.6%) experienced a recurrence, half of them experiencing it within the first year after the initial episode. The highest incidence of anaphylaxis was observed in children and adolescents, followed by middle-aged adults. A rapid increase in anaphylaxis cases was observed from 2002 to 2006 (Annual Percentage Change [APC], 33.2), followed by a more gradual increase until 2013 (APC, 12.8), and a stable trend from 2013 to 2019 (APC, 0.61). Males and adult age groups exhibited an increased risk of recurrence. Living in an area with neighborhood deprivation and the presence of comorbid conditions were associated with increased recurrence risk. CONCLUSIONS: The increasing prevalence of anaphylaxis and its association with certain risk factors calls for targeted intervention. Addressing neighborhood deprivation and comorbid conditions may aid in reducing the recurrence and overall burden of anaphylaxis.