Differences in Adherence Barriers to Inhaled Medicines between Japanese Patients with Chronic Obstructive Pulmonary Disease and Asthma Evaluated using the “Adherence Starts with Knowledge 20” (ASK-20) Questionnaire

OBJECTIVE: This multicenter, cross-sectional, non-interventional trial aimed to investigate adherence barriers to inhaled medicines when compared with oral medicines in Japanese patients with chronic obstructive pulmonary disease (COPD) and asthma. METHODS: The self-reporting “Adherence Starts with Knowledge 20” (ASK-20) questionnaire was administered for adherence barriers of inhaled and oral medicines to outpatients with regular clinic attendance. RESULTS: Patients with COPD and asthma reported different adherence barriers to inhaled medicines. Independent adherence barriers [odds ratio (95% confidence interval)] to inhaled medicines relative to those for oral medicines among patients with COPD and asthma were those related to item Q8 [“I know if I am reaching my health goals”; 2.49 (1.39-4.47); p=0.0022] and item Q2 [“I run out of my medicine because I do not get refills on time”; 2.69 (1.26-5.75); p=0.0127], respectively. Among patients with poor adherence to only inhaled medicines, those with COPD and asthma recognized item Q3 [“consuming alcohol and taking medicines”; 6.63 (1.27-34.7); p<0.05] and item Q1 [“forget to take medicines only sometimes”; 4.29 (1.83-10.0); p<0.05], respectively, were recognized as independent adherence barriers to inhaled medicines. The total ASK-20 scores and total barrier counts in patients with poor adherence to inhaled medicines were significantly higher than in those without poor adherence among patients with asthma (p=0.0057) but not those with COPD (p>0.05). CONCLUSION: These results will aid in personalizing education on adherence to inhaled medicines among patients with COPD and asthma.