Autoinjector models
We identified seven randomised trials, two non-randomised controlled trials and one consecutive case series examining the usability of autoinjectors (supplement S5h). These encompassed heterogeneous types of autoinjectors and testers, including those at risk of anaphylaxis, healthy volunteers and healthcare professionals.
Some studies explored modifying autoinjectors, such as changing the colour of the safety cap, having an arrow pointing to the injection tip or using voice prompts to guide people through their use. Such modifications may slightly increase the proportion of people correctly using the devices (low certainty)11Arga M, Bakirtas A, Topal E, Yilmaz O, Hacer Ertoy Karagol I, Demirsoy MS, Turktas I. Effect of epinephrine autoinjector design on unintentional injection injury. Allergy Asthma Proc 2012;33(6):488-492.,22Bakirtas A, Arga M, Catal F, Derinoz O, Demirsoy MS, Turktas I. Make-up of the epinephrine autoinjector: the effect on its use by untrained users. Pediatr Allergy Immunol 2011;22(7):729-733.,33Umasunthar T, Procktor A, Hodes M, Smith JG, Gore C, Cox HE, Marrs T, Hanna H, Phillips K, Pinto C, Turner PJ, Warner JO, Boyle RJ. Patients’ ability to treat anaphylaxis using adrenaline autoinjectors: a randomized controlled trial. Allergy 2015;70(7):855-863.,44Robinson MN, Dharmage SC, Tang ML. Comparison of adrenaline auto-injector devices: ease of use and ability to recall use. Pediatr Allergy Immunol 2014;25(5):462-467.,55Guerlain S, Hugine A, Wang L. A comparison of 4 epinephrine autoinjector delivery systems: usability and patient preference. Ann Allergy Asthma Immunol 2010;104(2):172-177. and decrease the time taken to administer adrenaline (low certainty).66Arga M, Bakirtas A, Topal E, Yilmaz O, Hacer Ertoy Karagol I, Demirsoy MS, Turktas I. Effect of epinephrine autoinjector design on unintentional injection injury. Allergy Asthma Proc 2012;33(6):488-492.,77Bakirtas A, Arga M, Catal F, Derinoz O, Demirsoy MS, Turktas I. Make-up of the epinephrine autoinjector: the effect on its use by untrained users. Pediatr Allergy Immunol 2011;22(7):729-733.
It is unclear whether specific autoinjector models reduce the risk of unintentional injuries because the certainty of evidence is very low. Two trials in adults found that a modified EpiPen was associated with a 18% or 40% reduction in unintentional injuries compared to the ‘old’ EpiPen (very low certainty, statistically significant, confidence intervals not reported).88Arga M, Bakirtas A, Topal E, Yilmaz O, Hacer Ertoy Karagol I, Demirsoy MS, Turktas I. Effect of epinephrine autoinjector design on unintentional injection injury. Allergy Asthma Proc 2012;33(6):488-492.,99Bakirtas A, Arga M, Catal F, Derinoz O, Demirsoy MS, Turktas I. Make-up of the epinephrine autoinjector: the effect on its use by untrained users. Pediatr Allergy Immunol 2011;22(7):729-733. Another trial in mothers of children at risk of anaphylaxis found that Anapen was associated with a 14% decrease in unintentional injuries compared to EpiPen (very low certainty, statistically significant, CI not reported).1010Umasunthar T, Procktor A, Hodes M, Smith JG, Gore C, Cox HE, Marrs T, Hanna H, Phillips K, Pinto C, Turner PJ, Warner JO, Boyle RJ. Patients’ ability to treat anaphylaxis using adrenaline autoinjectors: a randomized controlled trial. Allergy 2015;70(7):855-863.