Use of complementary and alternative medicine for inflammatory bowel disease is associated with worse adherence to conventional therapy: The COMPLIANT study

Background: Complementary and alternative medicine (CAM) use is highly prevalent among inflammatory bowel disease (IBD patients). We assessed whether its use, both for IBD and for general health, influenced adherence to conventional medications. Methods: We enrolled 392 IBD subjects in a prospective cohort study and categorized them as CAM nonusers (38%) and those who used CAM for general health (CAM-GEN, 41%) and for IBD (CAM-IBD, 21%). Their self-reported adherence was measured using the 4-item Morisky Adherence Scale during a median follow-up period of 6.8 months. Results: CAM-IBD users were less likely to be adherent to medical therapy than CAM nonusers and CAM-GEN users (70% vs. 84% and 81%, respectively, P < 0.05). Nearly all subjects who were nonadherent reported that it was unintentional (97%), and this did not vary use of CAM. After adjusting for confounders, the adjusted odds ratio for adherence among CAM-IBD relative to CAM nonuser was 0.47 (95% CI, 0.22-0.96). CAM-GEN demonstrated similar adherence to CAM nonusers (adjusted odds ratio, 0.85; 95% CI, 0.44-1.66). CAM-IBD was also less likely than CAM nonusers and CAM-GEN to have improvement in their adherence scores during follow-up (14% vs. 33% and 34%, respectively, P < 0.01). The adjusted odds ratio for improved adherence in CAM-IBD compared with CAM nonusers and CAM-GEN were 0.32 (95% CI, 0.15-0.69) and 0.34 (95% CI, 0.16-0.72), respectively. Conclusions: CAM-IBD, but not CAM-GEN, was associated with lower adherence to IBD medical therapy. A third of CAM nonusers and CAM-GEN improved adherence during the observation period, suggesting a Hawthorne effect.