Atopic dermatitis occurrence and progression and allergen immunotherapy: A real-world, retrospective cohort study in Germany.

Background: Allergen immunotherapy (AIT) represents the sole causal and preventive disease-modifying therapy currently available for allergic diseases. However, it must be acknowledged that controlled studies feature inherent results bias due to specific criteria and monitoring during the study. This real-world evidence (RWE) study was therefore designed to analyse data on large longitudinal prescriptions of different types of AIT in order to evaluate the therapeutic effect on the progression and onset of atopic dermatitis (AD). Methods: The analysis was based on IQVIA™ LRx prescription data for statutorily insured patients in Germany. A total of 122,600 patients were included in the study, and we identified prescriptions of AIT for house dust mites (HDM), grasses (GR) and early flowering trees (EFT) from 2008 to 2017. We compared AIT groups to control groups, which were selected from patients not treated with AIT but with at least 2 prescriptions of symptomatic allergic rhinitis (AR) medication. We measured the impact of AIT treatment on AD using symptomatic AD medication. Results: The use of all 3 forms of AIT resulted in a significant decrease in the necessity for AD medication when compared to the control group. Moreover, in patients who did not present with AD at the outset of the study, AIT was observed to significantly reduce the likelihood of developing AD at a later stage, in comparison to allergic patients who were not subjected to AIT. Conclusion: Our results confirm the positive effects of AIT in patients with AD. The findings of this study illustrate the value of RWE studies as a means of further analysis of AIT as a disease modifier, thus providing a complementary perspective to that gained from clinical studies and enhancing the efficacy of AIT in the future.