Factors Associated with Adherence to Allergen Specific Subcutaneous Immunotherapy

PURPOSE: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.