Rate of recurrent anaphylaxis and associated risk factors among Olmsted County, Minnesota, residents: A population-based study

Background The rate and risk factors for recurrence of anaphylaxis are not well known. Objective To measure the rate and risk factors for recurrent anaphylaxis in a population-based cohort in Olmsted County, Minnesota. Methods We conducted a population-based cohort study using the Rochester Epidemiology Project, a comprehensive medical records linkage system, to obtain records of patients who presented to medical centers within the Olmsted County area with anaphylaxis from January 1, 2001, through December 31, 2010. We evaluated the rate and associations of risk factors with anaphylaxis recurrence. Results Among the 611 patients with anaphylaxis, 50 (8%) experienced a total of 60 recurrences within the 10-year period, resulting in a recurrence rate of 2.6 per 100 person-years. A history of atopic dermatitis (hazard ratio [HR], 5.6; 95% confidence interval [CI], 2.0–16.1; P = .001), presenting symptoms of cough (HR, 4.7; 95% CI, 2.1–10.7; P < .001) oral pruritus (HR, 9.9; 95% CI, 4.3–23.2; P < .001), and receiving corticosteroids (HR, 5.2; 95% CI, 2.3–11.7; P < .001) were associated with an increased risk of recurrence. The cardiovascular symptom of chest pain (HR, 0.24; 95% CI, 0.07–0.79; P = .02) was associated with a decreased risk of recurrence. Conclusion In this epidemiologic study, the rate of recurrence was 8% during the 10-year study period (recurrence rate of 2.6 per 100 person-years). Those with atopic dermatitis and mucocutaneous or respiratory symptoms were more likely to have a recurrent anaphylactic event. Our findings underscore the importance of early patient access to self-injectable epinephrine and referral to an allergist/immunologist for additional testing and education.