Adherence to therapy in patients with inflammatory bowel disease on subcutaneous biologic therapy

Introduction: Nonadherence is a problem in the treatment of chronic diseases including inflammatory bowel disease (IBD) and according to the literature, adherence is not sufficient in a quarter of patients. The consequence is an increased risk of treatment failure and disease relapse. Non-adherence plays a significant role in the case of home application of subcutaneous biological therapy (BT). The aim of this study is to evaluate the adherence of conventionally monitored IBD patients with subcutaneous BT in comparison with the use of telemedicine monitoring. Methods: Retrospective data from a single IBD centre on the frequency of visits and medication dispensed in patients were used to assess adherence, with the calculation of the Medication Possession Ratio (MPR). A cohort of patients managed using the IBD Assistant platform, with activated online notifications when an application was required, was compared with a control group of conventionally monitored IBD patients matched by treatment type, diagnosis, gender and age. A secondary endpoint was monitoring of serum drug levels in a subpopulation of adalimumab patients. Results: The study included 69 patients with subcutaneous BT active between July 2022 and July 2023 on the IBD Assistant platform. A control group of 138 conventionally monitored patients was matched to this group in a 2: 1 ratio. The mean age of the patients was 40.6 ± 11.1 years; 43.5% were male. Crohn‘s disease was diagnosed in 83.1% of patients. Adalimumab was administered to 91.3% of patients, 7.2% of patients received subcutaneous vedolizumab and 1.5% of patients received golimumab. Median follow-up was 517 days. Adherence as assessed by MPR was high in both the telemedicine and conventional groups (0.960 ± 0.084 vs. 0.967 ± 0.094; P = 0.6123). The proportion of non-adherent patients with MPR < 0.86 was 8.8% and 8.0%, respectively (P = NS). In the whole cohort, adherence was significantly lower in women and tended to be higher in patients with ulcerative colitis. Patient age did not play a role. The proportion of nonadherent patients was significantly higher in patients with low levels of adalimumab (36.8 vs. 4.9%; P = 0.0002). Conclusion: Although the overall adherence to subcutaneous BT is relatively high and independent of patient follow-up, MPR assessment can help identify at-risk patient groups. Low drug (adalimumab) levels are the result of nonadherence in one third of cases. Keywords inflammatory bowel disease, biologic therapy, adherence, medication possession ratio