Factors Associated with Adherence to Allergen Specific Subcutaneous Immunotherapy

Allergen-specific immunotherapy (AIT) is known to be the only therapeutic modality to alter the natural course of allergic diseases. However, at least 3 years of treatment is recommended for achieving long-term disease modifying effect. This study aimed to investigate factors associated with immunotherapy non-adherence in real practice.

We retrospectively reviewed medical records of patients who were diagnosed with allergic rhinitis, asthma, or atopic dermatitis, and received AIT to common allergens such as house dust mite and/or pollens from January 2007 to August 2014. In this study, non-adherence was defined as not completing 3 years of AIT.

Among 1162 patients enrolled, 228 (19.6%) failed to complete 3 years of AIT. In multivariate analysis, age less than 20 years [odds ratio (OR) 3.11, 95% confidence interval (CI) 1.70-5.69] and 20 to 40 years (OR 2.01, 95% CI 1.17-3.43), cluster build-up (OR 1.78, 95% CI 1.05-3.02) and ultra-rush build-up schedules (OR 5.46, 95% CI 2.40-12.43), and absence of visit to other departments in the same hospital (OR 1.87, 95% CI 1.05-3.32) were independently associated with immunotherapy non-adherence. Disease duration of 5-10 years was negatively associated with non-adherence compared to shorter disease duration of less than 5 years (OR 0.61, 95% CI 0.40-0.94). Although male sex and commercial product of AIT, Tyrosine S®, compared to Novo-Helisen® were non-adherent factors in univariate analysis, no statistical significances were identified in multivariate analysis.

Various factors are associated with immunotherapy adherence affecting the utility of immunotherapy. Clinicians should be aware of factors associated with adherence to maximize the utility of allergen-specific subcutaneous immunotherapy.