Patterns and Predictors of Long-term Nonuse of Medical Therapy Among Persons with Inflammatory Bowel Disease

To evaluate patterns and predictors of long-term nonuse of inflammatory bowel disease (IBD)-specific medications among patients with IBD.

All incident cases of IBD diagnosed between 1987 and 2012 were identified from the population-based University of Manitoba IBD Epidemiology Database. Point prevalence of long-term medication nonuse (defined as no receipt of IBD-specific medications for a year or longer) was determined over calendar time and the course of disease. Cox proportional hazard regression analysis was performed to identify factors associated with delayed initiation and with becoming a long-term nonuser.

Among 6451 persons with IBD followed since 1987 (46.8% male, 47.8% with Crohn's disease), 11.7% were not dispensed an IBD-specific medication within the first year and 6.2% within 5 years after diagnosis. Factors associated with delayed initiation included having Crohn's disease (hazard ratio [HR] = 0.78, 95% confidence interval [CI], 0.73-0.83), lower socioeconomic status (HR = 0.91, 95% CI, 0.84-0.98), age more than 65 years (HR = 0.76, 95% CI, 0.67-0.86), and having any medical comorbidity. The prevalence of long-term nonuse consistently remained between 40% and 50% of persons with IBD across the study years. Patients with Crohn's disease (HR = 1.14, 95% CI, 1.04-1.25), lower socioeconomic status (HR = 1.14, 95% CI, 1.02-1.27), patients with IBD-associated surgery (HR = 1.72, 95% CI, 1.51-1.96), or delayed initiation of first IBD medication were more likely to become long-term nonusers after initiation.

At any given time, roughly half of all patients with IBD have not used IBD-specific medications in the previous year. Further work is required to evaluate the clinical implications of long-term medication nonuse in IBD.