August 2, 2017

Allergen immunotherapy for allergic asthma: a systematic overview of systematic reviews

  • Felix Asamoah,
  • Artemisia Kakourou,
  • Sangeeta DhamiEmail authorView ORCID ID profile,
  • Susanne Lau,
  • Ioana Agache,
  • Antonella Muraro,
  • Graham Roberts,
  • Cezmi Akdis,
  • Matteo Bonini,
  • Ozlem Cavkaytar,
  • Breda Flood,
  • Kenji Izuhara,
  • Marek Jutel,
  • Ă–mer Kalayci,
  • Oliver Pfaar and
  • Aziz Sheikh
Contributed equally
Clinical and Translational Allergy20177:25

Abstract
Background
There is clinical uncertainty about the effectiveness and safety of allergen immunotherapy (AIT) for the treatment of allergic asthma.
Objectives
To undertake a systematic overview of the effectiveness, cost-effectiveness and safety of AIT for the treatment of allergic asthma.
Methods
We searched nine electronic databases from inception to October 31, 2015. Systematic reviews were independently screened by two reviewers against pre-defined eligibility criteria and critically appraised using the Critical Appraisal Skills Programme quality assessment tool for systematic reviews. Data were descriptively and thematically synthesized.
Results
We identified nine eligible systematic reviews; these focused on delivery of AIT through the following routes: subcutaneous (SCIT; n = 3); sublingual (SLIT; n = 4); and both SCIT and SLIT (n = 2). This evidence found that AIT delivered by SCIT and SLIT can improve medication and symptom scores and measures of bronchial hyper-reactivity. The impact on measures of lung function or asthma control was however less clear. We found no systematic review level evidence on the cost-effectiveness of SCIT or SLIT. SLIT had a favorable safety profile when compared to SCIT, particularly in relation to the risk of systemic reactions.
Conclusions
AIT has the potential to achieve reductions in symptom and medication scores, but there is no clear or consistent evidence that measures of lung function can be improved. Bearing in mind the limitations of synthesizing evidence from systematic reviews and the fact that these reviews include mainly dated studies, a systematic review of current primary studies is now needed to update this evidence base, estimate the effectiveness of AIT on asthma outcomes and to investigate the relative effectiveness, cost-effectiveness and safety of SCIT and SLIT.

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