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Original Research

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

, , , ORCID Icon &
Pages 1083-1092 | Published online: 02 Jul 2020
 

Abstract

Background

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.

Highlights

● Poor medication adherence in inflammatory bowel disease (IBD) had a negative impact on disease outcomes.

● Predictors of low adherence were young age, lesions on small intestine, whereas previous abdominal surgery was a protective factor.

● MMAS-8 scale was a valid instrument for assessing 5-ASA adherence in IBD patients.

Abbreviations

IBD, inflammatory bowel disease; CD, Crohn’s disease 16; UC, ulcerative colitis; MMAS, Morisky Medication Adherence Scale; MPR, Medication Possession Ratio; 5-ASA, 5-aminosalicylic acid; CCCF, The China Crohn’s & Colitis Foundation 17; HBI, Harvey- Bradshaw Index; P-SSCAI, Patient-based Simple Clinical Colitis Activity Index.

Disclosure

The authors declare no conflicts of interest in this work.

Additional information

Funding

This work was supported by research grants from Zhejiang Provincial National Science Foundation of China (grant number LY20H160031) and Intestinal Barrier Research Foundation of Lijieshou (grant number LJS-201703) to CPZ. This work was also supported by Ferring company, Shanghai, China.