AAAAI and ACAAI surveillance study of subcutaneous immunotherapy, Year 3: what practices modify the risk of systemic reactions?

Abstract

Objective: To define the incidence of and clinical practices associated with subcutaneous immunotherapy (SCIT)-related systemic reactions (SRs).

Methods: From 2008-2011, American Academy of Allergy, Asthma & Immunology and American College of Allergy, Asthma & Immunology members completed an annual survey of SCIT-related SRs of varying severity (with grade 1 indicating mild; grade 2, moderate; and grade 3, severe anaphylaxis). From 2010-2011 (year 3) data were collected regarding SCIT-related procedures, including screening of patients with asthma, dose adjustment during peak pollen seasons, build-up regimens (conventional, cluster, or rush), and premedication.

Results: No fatal reactions were directly or indirectly reported from 2008-2011. The SR rates were similar for all 3 years (0.1% of injection visits; 83% of practices), as were severity grades. On average, for all 3 years, there were 7.1 grade 1, 2.6 grade 2, and 0.4 grade 3 SRs per 10,000 injection visits. Screening for worsening asthma symptoms was highly prevalent (86% always screened). Practices that always reduced doses during peak pollen season were significantly less likely to report grade 2 or 3 SRs (44% vs 65%; P = .04). Cluster and rush build-up were associated with significantly more SRs (P < .001). Practices that premedicated were significantly more likely to report grade 2 and 3 SRs (P < .01).

Conclusion: Fatal reactions to SCIT appear to be declining, possibly related to almost universal screening of asthmatic patients. Adjusting doses during the pollen season may be associated with decreased risk for severe SRs. Cluster and rush immunotherapy were associated with increased risk for SRs. Premedication by practices reporting SRs likely reflects past experience with SRs.