Published Online: April 3, 2013
Allergic rhinitis, or hay fever, is known to have a substantial impact on quality-of-life, particularly where symptoms are poorly controlled by conventional treatment options (pharmacotherapy). Subcutaneous (SCIT) or sublingual (SLIT) immunotherapy is a treatment option in this patient group, and there is abundant evidence of the superiority of both types of immunotherapy over placebo. It remains uncertain, however, which mode of administration is more beneficial.
In a recent article in The Journal of Allergy & Clinical Immunology (JACI) Dretzke et al report that, based on a systematic review, existing head-to-head trials of SCIT versus SLIT provide very little evidence. They therefore conducted an indirect comparison based on placebo-controlled trials. Likely sources of heterogeneity stemming from allergen type, dose, duration of treatment, and the population (adults or children) were explored.
The indirect comparison found that statistically significant results based on symptom scores and medication scores favored SCIT, but it was not possible to fully correct for the substantial heterogeneity of studies. However, treatments appeared very similar when analysis was based on symptom-medication scores and quality-of-life scores, arguably preferred outcome measures, and heterogeneity were lower in these analyses. An exploratory analysis based on symptom scores found an increasing probability over time of SLIT being a more effective treatment compared with SCIT.
Substantial uncertainty remains associated with these findings, not least due to the variability in the use of outcome measures. Given the increasing evidence of immunotherapy’s role in preventing new sensitizations and progression to asthma, and a growing interest in prescribing the treatment more routinely, head-to-head trials based on validated outcome measures remain a priority.
The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.