Identifying the Causes Increasing the Risk of Non-Adherence in Adult Patients with Asthma: An Analysis Combining Patient Survey Data with German Claims Data

BACKGROUND: There exists a range of treatments in the management of asthma. Non-adherence to these medications has been identified as a factor negatively impacting the effects of treatment. OBJECTIVE: The objective of this study was to identify the potential barriers to medication adherence among adult patients with asthma in Germany. PATIENTS AND METHODS: A multi-center observational study was conducted addressing adult patients with asthma who were prescribed regular maintenance medication between 2014 and 2016. Data were derived from physicians’ documentation as well as claims data, which were linked to the above primary observational data, and patient survey data. Adherence barriers were assessed by the validated Adherence Barriers Questionnaire, both descriptively and in a logistic regression framework. Cluster analysis identified distinct patient groups with respect to the relevance of specific adherence barriers. RESULTS: We included 524 patients with asthma (mean age 53.1 years, 74.6% female, 43.1% allergic asthma, 37.6% nonallergic, 19.3% mixed). Most of the participants reported to face at least three barriers (61.1%). Frequently reported barriers were the perception that medications are all harmful (53.6% of the participants), the burden of medication co-payment (44.1%), positive perception about current health status (39.9%), feeling of depression (30.9%), and the fear of side effects (27.5%). Four distinct patient clusters could be identified: cluster 1 with a low number of barriers (28.6% of participants), cluster 2 (11.6%) with a comparably high number of existing barriers, cluster 3 with high importance of depression as a barrier (27.3% of participants), and cluster 4 that was dominated by the perception that medications are all harmful (32.5% of participants). CONCLUSIONS: Results of this study provide important insights for further development of adherence programs, which should focus on distinct patients’ clusters that differ substantially in the relevance of specific adherence barriers.