Fran Lowry

November 12, 2012

ANAHEIM, California — People with known allergies who make regular visits to their allergist or immunologist have a lower risk for severe anaphylaxis compared with their counterparts who do not, according to a study presented at a poster session here at the American College of Allergy, Asthma & Immunology (ACAAI) 2012 Annual Scientific Meeting.

"Severe allergic reactions, including life-threatening anaphylactic reactions, are common reasons for visits to emergency departments," lead author Sunday Clark, ScD, assistant professor of emergency medicine and public health at Weill Cornell Medical College, New York City, told Medscape Medical News.

"We undertook this study because we felt that if we could further understand some of the risk factors for severe allergic reaction, we might be able to provide some insight for physicians and patients about useful things they could do to try to avoid these types of reactions," Dr. Clark said.

They retrospectively reviewed claims data and identified 11,972 individuals (mean age, 42 years; range, 20 - 64 years; 58% women) with a visit to the emergency department or hospitalization for anaphylaxis between January 1, 2002, and December 31, 2008.

All individuals had continuous medical and drug insurance coverage for at least 1 year before and after the date of their initial emergency department visit.

Of these individuals, 2992 (25%) had severe anaphylaxis.

The unadjusted analysis showed that those with severe anaphylaxis were more likely to be older and have more comorbidities and were less likely to have filled a prescription for an epinephrine autoinjector or to have seen an allergist, but they were more likely to have gone to the emergency department or to have been hospitalized for an anaphylactic reaction.

The study also found that severe anaphylaxis was less likely to be triggered by food.

After adjusting for several potential confounders, including age and the presence of other comorbid conditions, the researchers found that individuals who saw an allergist or an immunologist and who had filled their prescription for an epinephrine autoinjector in the year before their initial hospital visit had less severe anaphylaxis.

The adjusted odds ratio (aOR) for people who filled their epinephrine autoinjector was 0.63 (95% confidence interval [CI], 0.53 - 0.77); the aOR for people who visited their allergist or immunologist was 0.77 (95% CI, 0.63 - 0.95).

Not seeing an allergist and not filling the prescription for an epinephrine autoinjector were linked to more severe anaphylaxis when patients presented to hospital.

Those who did not fill their prescription had an 18% higher risk of having severe anaphylaxis (aOR, 1.18; 95% CI, 1.07 - 1.30), and those who failed to see an allergist or immunologist had a 56% higher risk of having severe anaphylaxis (aOR, 1.56; 95% CI, 1.37 - 1.77).

Preventive Anaphylaxis Care Important

Dr. Clark said she hopes the study will raise awareness about the importance of preventive anaphylaxis care for individuals with known allergies.

"Seeing an allergist or an immunologist, understanding your allergy, and having a current, up-to-date epinephrine autoinjector prescription are, as we have shown in this study, so important," she said.

"Patients also need to know how to use that injector. They also must have an anaphylaxis action plan so they know what to do if they experience a reaction. Doctors also need to remind their patients how to take better care of themselves," she said.

"Although symptoms may not always be severe, allergies are serious, and sometimes they are deadly, but they can be effectively controlled with proper diagnosis and treatment by a board-certified allergist that involves more than just relieving symptoms but finding the source of the suffering," ACAAI President Stanley Fineman, MD, of Atlanta Allergy and Asthma Clinic in Georgia, told Medscape Medical News.

"This study provides good evidence that having an allergist and being prepared for allergic reactions with an epi-pen makes anaphylaxis reactions less severe," said Jay M. Portnoy, professor of pediatrics at the University of Missouri–Kansas City and Children's Mercy Hospital.

"If you have an allergist, you are less likely to have a more severe anaphylactic reaction. Allergists know this, and it is important to get this message out to general physicians and all people with allergies."

Dr. Clark has disclosed no relevant financial relationships. Dr. Fineman reports financial relationships with AstraZeneca, Genentech, and Sunovion. Dr. Portnoy reports financial relationships with ThermoFisher Scientific.

American College of Allergy, Asthma & Immunology (ACAAI) 2012 Annual Scientific Meeting: Abstract P8. Presented November 11, 2012.