WAO Anaphylaxis Guidelines-WAO Anaphylaxis Special Committee Epidemiology 7 December 2011 Workshop 25

Definition: Epidemiology “The study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to control of health problems” Stedman’s Medical Dictionary

Terminology Incidence is the number of NEW EVENTS of a condition in a particular time interval eg per year Prevalence is the number of cases of a condition existing in a population at a particular period in time (period prevalence) or particular moment in time (point prevalence) Prevalence is dependent on incidence and duration of the condition

World Allergy Organization Guidelines for the Assessment and Management of Anaphylaxis Simons FER, Ardusso LRF, Bilo MB, et al…………..WAO Journal 2011;4:13-37 “Lifetime prevalence based on international studies is estimated at %”

Epidemiology of Anaphylaxis: findings of the ACAAI Epidemiology of Anaphylaxis Working Group Ann Allergy Asthma Immunol 2006;97: Literature review from “Anaphylaxis is a relatively common problem, affecting up to 2% of the population” Prevalence over a lifetime is % “The largest number of incident cases is in children and adolescents”

6 Angioedema Urticaria Anaphylaxis (any) Poulos LM, et al. J Allergy Clin Immunol. 2007;120: Year Hospitalizations Per 100,000 Population ICD-10-AM introduced Australia ( ) Increasing Anaphylaxis Hospitalizations ICD-10-AM, International Classification of Diseases, 10th revision, Australian modification.

Year Hospitalizations Per 100,000 Lin RY, et al. Ann Allergy Asthma Immunol. 2008;101: New York ( ) Anaphylaxis Angioedema Urticaria Allergy unspecified Trend in Hospitalizations: First 2 Decades of Life

To Determine the Prevalence, Track the Antidote for the Condition Patients receiving self-injectable epinephrine from administrative data claims for outpatient treatment over 5 years (1.15 million persons) Data from retail pharmacies; patients had to self-pay Injectable epinephrine dispensed for outpatients in 0.95% of this population Likely an underestimate JACI 2002;110:647-51

JACI;2002:110: Dispensed Self-Injectable Epinephrine

Dispensed Self-Injectable Epinephrine In Children < 5 Years of Age

Events in Established Patients with Peanut and or Tree Nut Allergy

A voluntary registry for peanut and tree nut allergy: Characteristics of the first 5149 registrants JACI 2001;108: Structured questionnaire to self-identified peanut or tree nut allergic patients (n=7000) or health professional members (n= 1000) of the Food Allergy and Anaphylaxis Network and to 4000 members of the AAAAI Median age 5 years; mean 8.5 years; just 16 registrants were > 65 years

Self-Reported Information by Questionnaire re Peanut and or Tree Nuts Median age of first exposure to peanut was at 12 months; first reaction 14 months Median age for first exposure to tree nuts 24 months with first reaction at 36 months Isolated peanut allergy 68% Isolated tree nut allergy 9% Co-allergy 23%

14 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Self Reported Locations for Reactions to Peanut and Tree Nuts 1 st 2 nd 3 rd Home School Restaurant Relative/friend Other PeanutTree Nuts Sicherer S, et al. J Allergy Clin Immunol. 2001;108:

15 Severity of an Episode Not Predictable Sicherer SH, et al. J Allergy Clin Immunol. 2001;108: * * * * * 1st reaction 2nd reaction 3rd reaction SevereEpinephrine SevereEpinephrine Peanuts Tree Nuts Percent *Indicates a reaction more severe than the previous reaction.

Emergency Department Anaphylaxis: A Review of 142 Patients in a Single Year JACI 2001;108:861-6 Data collected from using ICD-9 codes (allergy/allergic reaction, anaphylactic shock or reaction, angioedema, urticaria) Tertiary referral, university-affiliated teaching hospital in Brisbane, Australia ED visits = 162 patients with acute allergic reactions (Urticaria etc) and 142 patients with anaphylaxis =

Emergency Department Anaphylaxis: A Review of 142 Patients in a Single Year Mean age 37 years; F/M 3:2 Potentially life threatening episode = 60 of the 142 patients (1 fatality) Annual incidence = 1:439 cases in ED and 1:1000 cases in ED = severe ….higher than 1:1100 cases in ED and 1:1500 cases that are severe reported in the literature Population incidence = 1:3400 people/year

Emergency Department Anaphylaxis: A Review of 142 Patients in a Single Year “One severe case can be expected every week in a moderate-sized department” “A precipitant will be recognized in approximately three-forths of cases….”

WAO White Book on Allergy 2011 Potential severe future reactions….”the more rapid the onset, the smaller the dose of the causative agent required to trigger reactions, and previous severe reactions” Risk factors for fatal outcomes…”underlying asthma, particularly if poorly controlled, and cardiovascular disease” Case fatality rate (proportion of anaphylaxis that is fatal) is < 1% or 1-5.5/million people/year

Fatal Anaphylaxis: postmortem findings and associated comorbid diseases Ann Allergy Asthma Immunol 2007;98: unselected cases over 12 years (2 with asthma) Mean age 59 years (17-91) 17 year old with asthma (shrimp) 91 year old with ischemic heart disease (ice cream, possibly peanuts)

Fatal Anaphylaxis (cont.) Onset of anaphylaxis in 30 minutes after exposure in 21/25 cases Death occurred within 60 minutes in 13/25 cases Urticaria was present in 1/25 cases on postmortem exam; 3 cases with flushing or generalized pruritus

Self-Injectable Epinephrine? Previous reactions in 8/25 ( one each for radiocontrast material, shrimp, clams, penicillin; 3 for Hymenoptera stings; 1 unknown food) Self-administered epinephrine was available and used in 1 case….unknown food

Is There an Effect of Atopy on Anaphylaxis? Yes No Foods Latex Radiocontrast material Asthma Idiopathic anaphylaxis Exercise induced anaphylaxis Penicillin Muscle relaxants Hymenoptera stings Insulin

Definition: Epidemiology “The study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to control of health problems” Stedman’s Medical Dictionary