Study Describes Rates of Adherence for Immunotherapy Methods in Allergic Rhinitis

Subcutaneous allergen immunotherapy (AIT) had significantly higher adherence rates compared to sublingual administration in a real-world setting, according to a paper published in the journal Patient Preference and Adherence.

Allergic rhinitis (AR) is a common chronic condition that frequently is a risk for asthma; 80% of those with asthma also have AR, and improved control of nasal allergies can also improve asthma control. Its prevalence is increasing and AR has a significant impact on quality of life.

In this study, investigators conducted a retrospective cohort analysis of a German longitudinal prescription database in order to analyze real-world adherence in patients receiving grass or tree allergen-specific immunotherapy prescriptions compared with those patients receiving non-AIT for symptomatic AR and asthma prescriptions. A second goal of the study was to determine the impact of AIT on the use of asthma and rhinitis medication, they added.

While AIT traditionally is administered via subcutaneous injection (SCIT), sublingual preparations (SLIT) can be administered at home after an initial, observed dose. This option may be more convenient for some patients, the authors explained. Clinical effectiveness is reached after AIT is given repeatedly for at least 3 years, but adeherence is often an issue and AIT is known for varied discontinuation rates.

There were 16,774 and 11,931 SCIT patients compared to 29,183 and 10,698 SLIT patients included in the analysis in the grass and tree groups, respectively. The study also included 5775 and 6263 SCIT patients and 3293 and 1565 for SLIT for the AR and asthma analysis, plus 90,175 and 82,655 control patients.

The investigators found that the AIT patients were more often younger, male, and treated by specialists in the AIT than the control group. Additionally, adherence to SCIT treatment was high throughout years 1 and 2, but dropped rapidly after 500 days. Adherence in this group reached 61.8% and 60.1% by the end of year 2 but dropped to 37.5% and 35% by the end of year 3 for the grasses and trees groups, respectively.

Adherence to SLIT was significantly lower in both grass and tree patients, the study authors found. For grass patients, the adherence rate was between 29.6% and 33.7% at the end of year 2 and between 9.6% and 13.4% at the end of year 3. In tree patients, the adherence rate was between 29.5% and 36.9% at the end of year 2, compared with 10.3% and 18.2% at the end of year 3.

Children, followed by adolescents, then adults, had the highest adherence rates for both AIT in the trees and grasses groups. Those using SCIT showed a “considerably greater” number of days on therapy than the SLIT patients for both grasses and tree allergens, the authors said.

The researchers also determined that patients treated with SCIT required about two-thirds fewer prescriptions for grass pollen allergens and 56% fewer prescriptions for tree allergens than the respective control groups. Those administering SLIT at the time numbered 53.6% for grass allergens and 46.5% for tree allergens, the investigators wrote.

Both forms of AIT reduced the need for asthma medications among patients allergic to grass pollen; however, the authors said SCIT was superior to SLIT in that regard for both adults and children. For tree pollen patients, only SCIT showed a significant reduction in asthma treatment for patients.

“Adherence to treatment is necessary for improving the efficacy of treatment in patients with allergic respiratory diseases, reducing healthcare costs, and for minimizing the disease’s burden on a patient’s life,” the authors wrote.

Reference

Vogelberg C, Brüggenjürgen B, Richter H, Jutel M Real-world adherence and evidence of subcutaneous and sublingual immunotherapy in grass and tree pollen-induced allergic rhinitis and asthma. Patient Prefer Adherence. Published online May 13, 2020. doi:10.2147/PPA.S242957