High refill-adherence to adalimumab is associated with low disease activity in patients with inflammatory bowel disease.

Purpose: Adalimumab has evolved to one of the more affordable first-line biologics for the treatment of inflammatory bowel disease (IBD), since its patent expired. However, poor adherence to adalimumab is a concern and may limit its effectiveness. It is plausible that good adherence improves treatment outcomes in IBD patients, but evidence is scarce. The aim of this study was to assess whether high refill-adherence (medication possession ratio (MPR) ≥ 80%) to adalimumab is associated with less active disease in IBD patients.

Methods: In this retrospective study, the MPR was used to assess refill-adherence of IBD patients using adalimumab. Disease activity was defined as a composite endpoint determined by endoscopy findings, laboratory results, validated questionnaires and clinical assessment by a gastroenterologist. Logistic regression was used to determine the association between high refill-adherence (MPR ≥ 80%) and disease activity.

Results: IBD was in remission in 72 of the 113 included patients and 41 had active disease at the time of the most recent prescription. Out of the patients who were in remission, 86.1% were adherent vs. 75.6% in patients with active disease. High refill-adherence was significantly associated with lower odds of active disease after adjustment for confounders: adjusted odds ratio 0.297, 95% confidence interval 0.099-0.892.

Conclusion: High refill-adherence to adalimumab therapy was associated with less active disease in IBD patients. Our results confirm the relevance of good adherence to adalimumab for achieving optimal treatment results, which may limit the need for switching to more expensive biologics.