Use of a screening tool to determine nonadherent behavior in inflammatory bowel disease

Nonadherence is an issue in the management of inflammatory bowel disease (IBD), and no validated screening tool is available. We aimed to determine whether scores from a self-reported adherence survey correlated with pharmacy refill data as a reliable measure of medication adherence.

We used the eight item, self-reported Morisky Medication Adherence Scale. Each question is worth a point, with a maximum score of 8. Pharmacies were contacted for refill information for the previous 3 months, then 3 and 6 months from enrollment. Refill data were recorded for each time interval as the medication possession ratio (MPR); adherence was defined as >80%. Analysis of variance was used to determine the relationship between survey scores and MPR by drug class.

One hundred fifty outpatients were enrolled, of whom 94 had Crohn's disease and 56 had ulcerative colitis; 89 were female. At baseline, 47% of patients were on 5-aminosalicylic acid (5-ASA), 54% an immunomodulator, 15% infliximab, 8% an injectable biologic, and 6% budesonide. The median adherence score was 7. Fifty-two percent stated they "rarely" missed a dose of medication. The median adherence score, as defined by refill data, ranged from 0% (injectable biologic) to 75% (infliximab) by drug class. Only those on an immunomodulator had a survey score that positively correlated with adherence.

Only those on a thiopurine were likely to have a score predicting adherence behavior. Adherence to therapy for IBD is complex and cannot be predicted reliably by a self-reported survey tool validated for other chronic conditions.