Development of an Inflammatory Bowel Disease-Specific Medication Adherence Instrument and Reasons for Non-adherence

Medication adherence impacts disease control in inflammatory bowel disease (IBD). Existing adherence measures such as the Morisky Medication Adherence Scale 8^© are often costly, non-medication-specific, and time-consuming.

We aimed to develop a non-proprietary, IBD-specific medication adherence instrument and to assess reasons for suboptimal medication adherence.

We developed the IBD Medication Adherence Tool to assess frequency of adherence and indications for missed or delayed medication doses. We co-administered the IBD Medication Adherence Tool and the Morisky Medication Adherence Scale 8^© (licensed for use) to participants enrolled in an internet-based cohort of adults with IBD and taking least one daily, oral IBD medication. We used Spearman's correlation to evaluate associations between the IBD Medication Adherence Tool and Morisky Medication Adherence Scale 8^©. We then categorized patients as sub-optimally adherent (IBD Medication Adherence Tool score 1-4) and highly adherent (score 5) and evaluated factors associated with and reasons for suboptimal adherence using multivariable analysis.

We evaluated 514 patients (73% female, mean age 49), of whom 21.4% had suboptimal adherence. IBD Medication Adherence Tool scores were moderately correlated with Morisky Medication Adherence Scale 8^© (r = 0.56, p < 0.001). The most commonly reported reasons for suboptimal adherence were forgetting, feeling well, and cost. Younger age and current smoking were associated with suboptimal adherence.

We developed a non-proprietary, IBD-specific tool to assess adherence to IBD medications, validated in a cohort of patients with IBD on daily, oral medications. Common reasons for suboptimal IBD medication adherence include forgetting, feeling well, and cost.