Anaphylaxis is a severe, multisystem allergic event. It is a medical emergency and can be fatal. A 2015 WAO update stated that Americans have a 1.6% risk of anaphylaxis over the course of their lifetime. In the US, anaphylaxis was fatal in 186-225 patients annually, a frequency of 0.63-0.76 per million people. 30-43% of patients with a history of anaphylaxis will have a recurrence.
Epinephrine is the only drug known to decrease the incidence of death from anaphylaxis and should be administered as the first-line agent. Delay in administration of epinephrine has been shown to directly increase the risk of death from anaphylaxis. The use of epinephrine autoinjectors by patients at risk of anaphylaxis is critically important to managing patient safety. Despite this, many patients do not have or do not use their epinephrine autoinjectors.
The use of epinephrine autoinjectors in anaphylaxis has been very well studied. A 2014 paper by Wood and colleagues reported the findings from surveying 35,079 patients. They found that 60% of patients did not have an epinephrine autoinjector on their person when anaphylaxis recurred. Another study by Sanchez found 9-28% of patients carried autoinjectors.
Wood found that 52% of patients with a history of anaphylaxis were never prescribed an autoinjector. In a patient group of 261 with history of proven anaphylaxis, a mere 11% used the autoinjector for their most recent anaphylactic event. Not using epinephrine in the appropriate time frame can have grave consequences. In anaphylaxis patients who progressed to cardiac arrest, 67% did not receive epinephrine within an hour of onset. Among patients who died from anaphylaxis, none of them received epinephrine when the first symptoms presented. Only 14% of fatal anaphylaxis patients were administered epinephrine prior to cardiac arrest.
In many instances, economics is to blame for not carrying an epinephrine autoinjector. A truly stunning statistic is that 50% of anaphylaxis patients do not fill prescriptions for autoinjectors once the cost is over $300. In the previously mentioned 2014 Wood publication, 41% of anaphylaxis patients reported a household income of less than $50,000. Despite being uniformly accepted as a medication used to prevent death and severe complications resulting from anaphylaxis, epinephrine autoinjectors are often not classified by insurance companies as a preventative medication. An analysis of American insurance plans found that the two pack of Epipens was classified as a tier 1 or 2 medication in 67% plans; tier 3 or 4 in 6% plans; “approved” without any contribution to the cost of the drug in 5% of plans; and 22% plans did not cover Epipens at all.
A 2012 paper assessed how patient cost related to adherence to treatment recommended by their provider for a wide array of conditions. Eaddy reported that of the 66 studies evaluated 85% (56 studies) demonstrated that patients were less likely to adhere to the treatment plan when their costs increased. High out-of-pocket costs were definitively shown to decrease patient use of preventative health care measures, resulting in poorer outcomes. Increasing copays and deductibles impede access to life saving medication for anaphylaxis patients. If epinephrine autoinjectors were classified universally as preventative medications, insurance companies would be obligated to fully cover the associated costs. They would also be prevented from requiring patients to pay large out of pocket costs for autoinjectors as contribution to deductibles.
Kaplan reported that only 11% of patients with a history of anaphylaxis refill their epinephrine autoinjectors as needed. Instead, many patients rely on expired autoinjectors. Epinephrine is an inherently unstable molecule that degrades quickly when exposed to oxygen or light. A study in 2000 showed that while autoinjectors still functioned as intended up to 90 months after expiration, epinephrine concentration was significantly reduced. Still, expired epinephrine is still better than no epinephrine in the event of anaphylaxis as the benefit would outweigh the risk.
Epinephrine autoinjectors are designed to be stored at 20-25°C but tolerate occasional exposure to higher or lower temperatures in the range of 15-30°C. While heat is known to hasten degradation of epinephrine, freezing apparently is not. The 2015 WAO update mentioned that if autoinjectors are frozen, epinephrine concentration is not affected and that patients can use them as long as they are completely thawed. (I find this really wild, I had never heard of this before.)
Exorbitant costs prevent anaphylaxis patients from having ready access to epinephrine autoinjectors, the only first line medication for anaphylaxis. 50% of patients do not fill prescriptions for epinephrine autoinjectors when their cost is over $300. With the cost of autoinjectors well into the hundreds of dollars for many patients, millions of people in the US may be unable to afford this lifesaving medication for which is there is no alternative.
Simons FER, et al. 2015 update of the evidence base: World Allergy Organization anaphylaxis guidelines. World Allergy Organization Journal 2015: 8(32).
Wood RA, et al. Anaphylaxis in America The prevalence and characteristics of anaphylaxis in the United States. J Allergy Clin Immunol 2014: 133, 461-467.
Noimark L, et al. The use of adrenaline autoinjectors by children and teenagers. Clinical & Experimental Allergy 2012: 42(2), 284-292. Eaddy MT, et al. How patient cost-sharing trends affect adherence and outcomes. Pharmacy & Therapeutics 2012: 37(1), 45-55.
Simons FER, et al. Outdated EpiPen and EpiPen Jr autoinjectors: Past their prime? J Allergy Clin Immunol 2000: 105(5), 1025-1030.
Sanchez J. Anaphylaxis. How often patients carry epinephrine in real life? Rev Alerg Mex 2013: 60, 168-171.
Kaplan MS, et al. Epinephrine autoinjector refill history in an HMO. Curr Allergy Asthma Rep 2011: 11, 65-70.)
Kim JS, et al. Parental use of EpiPen for children with food allergies. J Allergy Clin Immunol 2005: 116(1), 164-168.