Allergen immunotherapy effectiveness confirmed in long-term real-world study

3rd December 2021

Allergen immunotherapy in patients with allergic rhinitis and/or asthma was effective over a 9-year period in a real-world study

The effectiveness of allergen immunotherapy (AIT) in allergic rhinitis (AR) patients both with and without asthma has been confirmed in a 9-year retrospective analysis by researchers from the Paediatric Pulmonology and Allergy, Children’s Doctor Service, Heidelberg, Germany.

Allergies represent an abnormal immune system reaction to otherwise harmless allergens and in the UK, AR is estimated to affect 10-15% of children and 26% of adults. In addition, patients with AR can also suffer with asthma as a co-morbidity, with studies suggesting that 10% to 40% of AR patients have asthma. Furthermore, the presence of AR is associated with an incremental adverse impact on the disease-specific quality of life in patients with asthma and the level of asthma control.

Allergen immunotherapy (or desensitisation treatment) involves exposure to increasing doses of an allergen such as grass pollen, dust mite, or cat dander. AIT can be given via the subcutaneous or sublingual route, both of which have been shown to be effective treatment for patients with AR. Nevertheless, there is a recognised lack of information from studies on the effectiveness of AIT in real-world studies and over the longer term.

In order to address this gap in the evidence, the German researchers undertook the Real World effectiveness in allergy immunotherapy (REACT) study, primarily to assess the efficacy of AIT over a period of years. Using a retrospective, observational, propensity score matched cohort study, the team analysed health insurance claims from 2007 to 2017 and included AR patients with and without asthma and who had received an AIT prescription. These individuals were then propensity-score matched with AR individuals (also with or without asthma) but who had not been prescribed AIT. The primary outcome of the study was set as AR prescriptions in each follow-up year and secondary outcomes included asthma prescriptions, severe asthma exacerbations and any changes in the individual’s asthma treatment steps.

Findings

Between 2007 and 2017, 115,098 individuals had at least one AIT prescription, of whom, 46,024 with a mean age of 29.5 years (53% male) were propensity score matched. In addition, 14,614 AR patients with AR and co-existing asthma (mean age, 28.3 years, 54% male) were also matched with controls. However, over the 9 years, the study population declined, leaving 3692 individuals in the main cohort and 1142 with co-existent asthma.

When compared to control patients, AIT use was consistently associated with greater reductions in both AR and asthma prescriptions. In addition, there was a significantly greater likelihood that patients using AIT would have an asthma treatment step-down (p < 0.0001) and a reduction in severe asthma exacerbations (p < 0.05).

The authors concluded that their study had confirmed the real-world effectiveness of AIT as evidenced by sustained reductions in AR and asthma prescriptions, prevention of asthma exacerbations, and improved and sustained long-term asthma control.

Citation

Fritzching B et al. Long-term real-world effectiveness of allergy immunotherapy in patients with allergic rhinitis and asthma: Results from the REACT study, a retrospective cohort study. Lancet Regional Health Europe 2021