Background: Nonadherence to medications is common with patients with inflammatory bowel disease (IBD). The aim of this study was to assess adherence to biologic medications prescribed for IBD and to identify risk factors for biologic nonadherence.
Methods: This was a single center retrospective cohort study investigating IBD patient adherence to biologic therapies over a 2-year period from September 2014 to September 2016. Specialty pharmacy and infusion center records were obtained and a modified medication possession ratio was calculated. Patient characteristics associated with nonadherence in a univariate model were placed into a multivariate logistic regression to assess independent predictors of nonadherence.
Results: Three hundred sixty-five patients met inclusion criteria; 63 patients were on vedolizumab. Three hundred and one patients (82%) had Crohn's disease. The pooled 24-month adherence rate was 66%; adherence to individual biologic therapy included vedolizumab 83%, infliximab 70%, adalimumab 57%, and certolizumab pegol 50%. Facility-administered biologics were independently associated with higher adherence than self-administered biologics (OR 2.39, 95% CI 1.50 - 3.80). Additional risk factors for nonadherence included younger age (OR 1.22, 95% CI 1.01-1.47) and noncommercial insurance (OR 1.78, 95% CI 1.01 - 3.13).
Conclusions: This is the first study to assess adherence to vedolizumab in IBD patients, which was higher than 3 other commonly prescribed biologic medications. Self-administered injections were strongly associated with biologic nonadherence. Younger age and noncommercial insurance also were associated with biologic nonadherence. Modality of administration should be taken into account when selecting a biologic agent for treatment of IBD.
Keywords: adherence; biologic; inflammatory bowel disease; vedolizumab.
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