Three-Year Follow-up Results of Sublingual Immunotherapy in Patients With Allergic Rhinitis Sensitized to House Dust Mites

PURPOSE This study investigated the long-term efficacy, safety, and compliance associated with sublingual immunotherapy (SLIT) in Korean patients with allergic rhinitis sensitized to house dust mites. METHODS This is a retrospective cohort study. A total of 164 patients who were sensitized to Dermatophagoides pteronyssinus and Dermatophagoides farinae and who received SLIT were enrolled between November 2007 and January 2010. Each patient was followed up using a diary card, on which a symptom score, rescue medication score, and adverse events (AEs) were recorded. RESULTS All allergic rhinitis symptoms improved after 3 years of SLIT (P<0.05), and the rescue medication score decreased with time (P<0.05). The incidence of AEs associated with SLIT was 31% (51 of 164 patients) during the first month of therapy, and there were no severe AEs. The dropout rate was 19.5% (32 of 164 patients) during the first month, 34% (56 of 164 patients) after 6 months, and 41% (68 of 164 patients) after 1 year of SLIT. The 3-year compliance rate was approximately 40% (65 of 164 patients). The most common causes of dropout during the first month of SLIT were high cost and inconvenience. The improvement in allergic symptoms was the most common cause of dropout after 6 months. CONCLUSIONS Allergic symptoms significantly decreased after 1 year of SLIT treatment, and this effect was sustained after 2 or 3 years of treatment. By increasing compliance through patient education, the 3-year use of SLIT for house dust mite allergies may be effective in the management of allergic rhinitis.