Risk factors for fatal and nonfatal reactions to subcutaneous immunotherapy: National surveillance study on allergen immunotherapy (2008–2013)

Abstract

BackgroundIn 2008, an annual surveillance study of systemic reactions (SRs) from subcutaneous immunotherapy (SCIT) injections was initiated in North America. ObjectiveTo define the incidence of SRs to SCIT. MethodsFrom 2008 to 2013, 27% to 51% of American Academy of Allergy, Asthma, and Immunology and American College of Asthma, Allergy, and Immunology members completed an annual survey of SCIT-related SRs of varying severity. From 2012 to 2013, data were collected regarding SRs with off-label sublingual immunotherapy (SLIT), selection of patients with asthma for SCIT, and strategies for dose adjustment during pollen seasons. ResultsFrom 2008 to 2013, data were gathered on 28.9 million injection visits, including 344,480 patients for 2012 to 2013. Since 2008, a total of 2 confirmed fatalities were directly reported that occurred under the care of allergists. Two additional fatalities occurred under the care of nonallergists. The rate of SRs from SCIT remained stable, occurring in 1.9% of patients, with 0.08% and 0.02% experiencing grade 3 and 4 SRs. SRs occurred in 1.4% of patients receiving off-label SLIT, including 0.03% with grade 3 SRs. There were no SLIT-related grade 4 SRs or fatalities. Practices that never administered SCIT in patients with uncontrolled asthma (Asthma Control Test score <20) had significantly fewer grade 3 and 4 SRs (odds ratio, 0.7; 95% confidence interval, 0.5–1.0, and odds ratio, 0.3; 95% confidence interval, 0.1–0.8, respectively). Lowering doses during pollen seasons for patients with highly positive skin tests reduced SRs of all severity grades (P < .05). ConclusionsSCIT-related fatality rates may be decreasing, but continued vigilance regarding modifiable risk factors, including careful patient selection, is needed. Dose adjustment during pollen seasons for highly sensitive patients may reduce risks. Potential risk for SRs from off-label SLIT exists.