Comparison of evidence of treatment effects in randomized and nonrandomized studies on allergen immunotherapy

Nonrandomized studies (NRS) on allergen immunotherapy (AIT) particularly lend themselves to evaluate outcomes that are insufficiently addressed in randomized controlled studies (RCTs). However, NRS are prone to several sources of bias, which limit their validity. We aimed at comparing AIT effects between RCTs and NRS and evaluate the reasons for discrepancies in study results. In this analysis, we compared NRS on AIT (including subcutaneous and …