Specific immunotherapy for allergic rhinitis to grass and tree pollens in daily medical practice-symptom load with sublingual immunotherapy compared to subcutaneous immunotherapy.

Abstract Background. Despite strong evidence for subcutaneous and sublingual immunotherapy for the treatment of allergic rhinoconjunctivitis, comparative data are scarce. Objectives. We performed an individual patient data meta-analysis of four observational studies to compare the effectiveness of both application routes. Methods. After individual analysis, a subsequent analysis of the total data pool was performed. Descriptive and explorative data analysis methods were used. Results. Altogether 847 patients (382 male, 453 female) aged 3-78 years (mean age 28.3 years) were treated with specific immunotherapy: 665 (78.5%) patients sublingual and 182 (21.5%) subcutaneous. The majority of patients (61.6%) in both treatment groups started specific immunotherapy due to severe rhinitis symptoms which occurred frequently or very frequently. Most patients in both treatment groups had moderate to severe conjunctivitis symptom load which occurred frequently or very frequently. Median rhinitis and conjunctivitis symptom loads decreased during both treatments to the same extent. Similar improvements in the symptom loads were observed in patients stratified for age, disease duration, and presence or absence of mild to moderate asthma. Conclusion. The effectiveness of sublingual and subcutaneous immunotherapy with pollen extracts appeared virtually equal in daily medical routine. Due to the advantageous safety profile, the sublingual application may be favorable.