D1.152 - Incidence of patients who needed to change their allergy immunotherapy product specific to mites or pollens in Spanish allergy unitsIncidence of switching specific allergic immunotherapy products in Spanish allergy units

Specific allergic immunotherapy (AIT) is the only etiological treatment for allergic diseases. However, it has been observed that some patients, despite having been adequately diagnosed and treated with AIT, may experience lack of efficacy, adherence problems or side effects that may lead to discontinuation of treatment. At present, the frequency with which AIT product changes occur is unknown, as well as the reasons for this change in clinical practice.

An observational, descriptive, retrospective, multicenter study was carried out, including information from subjects over five years of age diagnosed with allergic rhinitis and/or asthma stratified into four groups: patients with a change in AIT treatment to pollen or mites and patients with "de novo" AIT to pollen or mites.

Information from 1423 patients in 107 allergy units was included: 368 patients belonged to the AIT switch group and 1056 to the "de novo" AIT group. The annual incidence of initiation of AIT treatment was 10.5% (95%CI 8.1-12.8). The annual incidence of AIT switch in pollen-allergic patients was 0.5% (95%CI 0.2-0.8), and 0.4% (95%CI 0.3-0.5) in dust mite-allergic patients. No significant differences were found in patient characteristics between the two groups. The main reason for switching AIT was lack of efficacy (76.9%) followed by seeking to improve the patient's quality of life (50.5%). The choice of "de novo" AIT products was based on their optimal dose content, composition and appropriate allergenic profile as well as on scientific evidence and previous experience of the allergist.

This study shows a low incidence of switching specific allergic immunotherapy products, with lack of efficacy being the main reason. These findings underline the need to evaluate the effectiveness of treatment switching and highlight the importance of personalized follow-up to optimize treatment response and promote long-term adherence.