Assessing Oral Medication Adherence and Identifying Predictors of Low Adherence in Chinese Inflammatory Bowel Disease Patients

• Main Authors: Hu W, Hu S, Zhu Y, Chen H, Chen Y
• Format: Article
• Language: English
• Published: Dove Medical Press 2020-07-01
• Series: Patient Preference and Adherence
• Subjects: inflammatory bowel disease; medication adherence; self-reported morisky medication adherence scale; medication possession ratio
• Online Access: https://www.dovepress.com/assessing-oral-medication-adherence-and-identifying-predictors-of-low--peer-reviewed-article-PPA

Wen Hu,* Shurong Hu,* Yimiao Zhu, Hanwen Chen, Yan Chen Center for Inflammatory Bowel Diseases, Department of Gastroenterology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, People’s Republic of China*These authors contributed equally to this workCorrespondence: Yan Chen Tel [phone]Email [e-mail]: Poor medication adherence in inflammatory bowel disease (IBD) had a negative impact on disease outcomes. In this study, we aimed to determine predictors of low adherence in the Chinese IBD populations and also aimed to compare a self-reported scale to a pharmacy refill index in assessing adherence of 5-ASA and azathioprine taken by Chinese IBD patients.Patients and Methods: Adult patients with IBD who had been taking 5-ASA or azathioprine for at least 3 months were recruited from hospital outpatient clinics. The MPR was calculated from previous six-month pharmacy refill data and the self-reported Morisky Medication Adherence Scale (MMAS-8) was issued through QR code questionnaires. Intentional and unintentional adherence scores were calculated according to specific items. Non-adherence was defined as MMAS-8 scores < 6 or MPR < 0.8.Results: The response rate in the IBD patients was as high as 97%. 5-ASA non-adherence rate assessed by MPR was 30% and 37% by MMAS-8, and azathioprine non-adherence rate assessed was 33% by both MPR and MMAS-8. In a linear regression analysis, MPR value was significantly correlated with MMAS-8 score in 5-ASA group (r=0.4, p=0.003), and significantly correlated with unintentional adherence score (r=0.47, p< 0.001). No significant correlation was observed between MPR value and MMAS-8 score in azathioprine group. Multivariate analysis demonstrated that age (OR: 1.08; 95% CI: 1.02– 1.13; P=0.0015) and previous abdominal surgery (OR: 3.18; 95% CI: 2.09– 4.27; P=0.04) were associated with high medication adherence. While patients who had small intestine lesion (OR: 0.09; 95% CI: 0.01– 0.17; P=0.006) were associated with low adherence.Conclusion: Predictors of low adherence were young age, lesions on small intestine, whereas previous abdominal surgery was a protective factor. This study also demonstrated that the MMAS-8 scale was a valid instrument for assessing 5-ASA adherence in IBD patients. Unintentional non-adherence was significantly related to the total non-adherence, which would allow to use the tool to seek ways for adherence improvement.Keywords: inflammatory bowel disease, medication adherence, self-reported Morisky Medication Adherence Scale, Medication possession ratio