ABSTRACT
BACKGROUND: In inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), nonadherence to biologic therapy increases risk of disease flare. The aim of this study was to identify risk factors for nonadherence. METHODS: This was a single-center retrospective study evaluating patients with IBD treated at a tertiary care center and prescribed self-injectable biologic therapy using the center's specialty pharmacy. Adherence was defined using medication possession ratio (MPR). Nonadherence was defined as MPR <0.86. RESULTS: Four hundred sixty patients (n = 393 with CD and n = 67 with UC) were evaluated with mean MPR (interquartile range) equaling 0.89 (0.48-1). Overall, 69% of patients were adherent (defined as MPR ≥0.86), 66% of patients with CD and 87% of patients with UC. In univariate analysis, several factors increased risk of nonadherence: CD diagnosis, insurance type, psychiatric history, smoking, prior biologic use, and narcotic use (P < 0.05). In multivariable analysis, Medicaid insurance (odds ratio [OR], 5.5; 95% confidence interval [CI], 1.85-15.6) and CD diagnosis (OR, 2.8; 95% CI, 1.3-6.0) increased risk of nonadherence. In CD, as the number of risk factors increased (narcotic use, psychiatric history, prior biologic use, and smoking), the probability of nonadherence increased. Adherence was 72% in patients with 0-1 risk factors, decreasing to 62%, 61%, and 42% in patients with 2, 3, and 4 risk factors, respectively (P < 0.05). CONCLUSIONS: This study identified risk factors for nonadherence to biologic therapy. In patients with CD, the probability of nonadherence increased as the number of risk factors increased.