Background: Nonadherence to medications may affect disease outcomes. The aim of this article was to review methods of assessment, prevalence, and predictors of nonadherence to anti-tumor necrosis factor therapy in inflammatory bowel diseases (IBD).
Methods: Studies were identified through the electronic database of MEDLINE (up to January 2012) and the annual meetings of Digestive Disease Week, the American College of Gastroenterology, the United European Gastroenterology Week, and the European Crohn's and Colitis Organization.
Results: Among 1783 citations identified, 13 studies evaluated adherence to biologics in IBD. Several methods were used to assess adherence to anti-tumor necrosis factor, including the medication possession ratio, the medication refill adherence, and the Morisky Medication Adherence Scale 8. Pooled adherence to anti-tumor necrosis factor therapy was 82.6%. Pooled adherence was 83.1% in adalimumab and 70.7% in infliximab-treated patients. Female gender, smoking, constraints related to treatment, anxiety, and moodiness were associated with nonadherence to both infliximab and adalimumab. Concomitant immunomodulator use and time since first infusion more than 18 weeks were predictors for nonadherence to infliximab . Regimen of 40 mg every other week, syringe use (versus pen), internal medicine center prescription (versus gastroenterology center prescription), retail pharmacy (versus speciality pharmacy) and new user (versus previous user) were predictors for adalimumab nonadherence.
Conclusions: More than three-quarters of patients with IBD adhere to biologics. Predictors of nonadherence include female gender, smoking, constraints related to treatment, anxiety, and moodiness. These data could be used to develop intervention studies aimed at improving adherence to biologics in IBD.