Adherence to subcutaneous biologic treatment for inflammatory bowel disease

Background: Nonadherence to medication is common in patients with inflammatory bowel disease (IBD) and can result in disease complications, therapy escalation, and the need for corticosteroids. The aim of this study was to assess the adherence to self-administered subcutaneous biologic medications prescribed for IBD and to identify the risk factors for nonadherence.

Methods: A retrospective cohort study on IBD patients initiated on subcutaneous biologic therapy between January 2016 and July 2019 was performed. Medical records were retrospectively reviewed for collection of demographic and IBD data. Medication possession ratios (mMPRs) during the first 12 months of treatment and at the end of the follow-up period (global, 42 months) were calculated. Nonadherence was defined as an mMPR of <90%. Multiple regression analysis was performed to assess the risk factors for nonadherence to therapy.

Results: A total of 154 patients (84 male and 70 female; mean age at biologic treatment initiation, 36±14 years; Crohn's disease, n=118; ulcerative colitis, n=31; indeterminate colitis, n=5) were included; 121 received adalimumab (ADA) and 33 received ustekinumab (UST); 63% were naive to anti-TNF therapy, while 16.9% previously received more than two biologic treatments. Mean time from IBD diagnosis to subcutaneous biological agent use was 16±10 months. Mean duration of subcutaneous agent use was 17.6 (SD, 11.0) and 17.08 (SD, 6.8) months for ADA and UST, respectively. Global nonadherence (mMPR≤90%) rate was 6.6% for all patients receiving subcutaneous treatment, 6.3% for ADA, and 6.5% for UST. Nonadherence during the first 12 months of treatment (n=98) was 6.1% for all patients, 2.7% for ADA, and 16% for UST. In the multivariate analysis, UST use was independently associated with higher nonadherence only within the first 12 months (OR, 6.7; 95% CI, 1.1-39.5).

Conclusions: High global adherence to self-administered subcutaneous biologic treatment was shown in our study, with higher rates of adherence to ADA than to UST within the first 12 months.