Course of respiratory allergy by treatment strategy based on German routine data.

Purpose: Allergic respiratory diseases represent a global health problem. The two major treatment strategies are symptom treatment and specific immunotherapy (SIT). SIT is considered the only causal treatment option available with the ability to alter the course of the disease. This study aims to describe the course of disease and medication of respiratory allergy across treatment strategies and disease groups.

Methods: The analysis is based on routine data from a German statutory health insurance. The patient cohort is observed from 2007-2012. For each year based on assured outpatient diagnoses patients are assigned to a disease group: rhinitis, asthma or both diseases. Additionally, prescribed medication is considered. Treatment comparisons are based on matched pairs.

Results: The study population comprises 165,446 patients with respiratory allergy. In 2007 the most frequent disease group is rhinitis (70%), followed by asthma (16%) and both diseases (14%). During the observation period a second allergic respiratory diagnosis occurs only in about 12% of rhinitis patients and 28% of asthma patients. In about 50% of patients with both diseases one of the diagnoses is omitted. These patients are more likely to no longer report their asthma diagnosis when receiving immunotherapy compared to symptom treatment. Furthermore immunotherapy reduces the frequency of asthma medication use.

Conclusions: Results of detailed analysis of diagnoses reflect the alternating nature of allergic diseases. Although limited by accuracy of documentation and the lack of clinical information, the comparison of treatment strategies shows some advantages of immunotherapy regarding course of disease and asthma medication use.