Self-Reported Medication Adherence Among Patients with Ulcerative Colitis in Japan and the United Kingdom: A Secondary Analysis for Cross-Cultural Comparison

PURPOSE: Non-adherence to medication was reported by 28% of Japanese patients with ulcerative colitis, but in the United Kingdom, patients with inflammatory bowel disease have lower medication adherence, which increases clinical relapse risk. The objective of this study was to compare medication adherence among patients with ulcerative colitis in Japan with previously reported results and patients in the United Kingdom. PATIENTS AND METHODS: This cross-cultural comparison study investigated medication adherence among 100 ulcerative colitis patients in the United Kingdom and 432 ulcerative colitis patients in Japan. Adherence was assessed using The Morisky Medication Adherence Scale-8 questionnaire. Patient clinical features were collected from medical records and the questionnaire. Distribution of responses for each item, questionnaire total score, difference in ratio for each item between Japanese and UK patients, and difference in percentage of low/medium/high adherence between Japanese and UK patients were compared. RESULTS: The proportion of low/medium or high adherence was significantly different between countries (42.6% and 7.4% [Japan] vs 24.0% and 76.0% [United Kingdom]; p<0.01). Significantly more Japanese patients reported taking medication correctly the day before the questionnaire compared with UK patients. CONCLUSION: UK patients were more likely to not take medication when they felt their symptoms were under control compared with Japanese patients. UK patients perceived it was more difficult to remember to take the medication than Japanese patients. This study highlights culturally sensitive medication-taking behaviors in Japanese and UK patients with ulcerative colitis.