N02 Therapeutic Adherence to Subcutaneous biologic agents in patients with inflammatory bowel disease: a single Centre retrospective observational study

Abstract Background Therapeutic adherence to subcutaneous(SC)biologic agents in inflammatory bowel disease(IBD)patients is a key determinant of clinical remission, reduced hospitalization, and improved quality of life.Real-world Italian data on adherence patterns remain limited, especially regarding recently introduced SC formulations Methods This retrospective observational study included adult patients diagnosed with Crohn’s disease or ulcerative colitis who initiated SC biologics (adalimumab, infliximab, ustekinumab, golimumab, vedolizumab SC) between January 2019 and December 2024 at the ASUFC (Udine, Italy).Data were obtained from electronic health records and pharmacy dispensing archives. Adherence was assessed using Medication Possession Ratio (MPR ≥80% considered adherent).Secondary outcomes included persistence, switching, and predictors of non-adherence evaluated through multivariate regression. Results A total of 132 patients were included (mean age 42 ( ± 16) years; 58% male; 68% Crohn’s disease).Median follow-up was 18.6 months, while median (95% CI) treatment persistence was 34 9, 58 months. Overall adherence rate was 92% (MPR ≥80%). Ustekinumab showed the highest adherence (mean MPR 97% ( ± 12)), followed by Adalimumab (mean MPR 95% ( ± 12)).During the observation period, 16 patients (12%) switched to a second subcutaneous biologic, while 48 individuals (36%) discontinued therapy.Patients treated with an anti-TNF-alpha agent had a higher probability of switching (17%) compared with those treated with Ustekinumab or Vedolizumab (4%; p = 0.037).Adherence was lower among individuals who discontinued treatment (mean MPR 92% (+-16)) compared with those who did not experience treatment failure (mean MPR 98% (+-6);p = 0.01).Moreover, therapy failure was associated with sex, 47% of females discontinuing treatment versus 28% of males (p = 0.02).Younger age, sex and diagnosis where not associated with adherence, suggesting that these factors do not significantly influence treatment adherence in this cohort. Conclusion Adherence to SC biologics in this real-world Italian IBD cohort was generally high,with variability across agents.Early identification higher risk patients of non-adherence could improve therapeutic outcomes.Targeted nursing interventions including structured education programs, periodic adherence monitoring, nurse-led outpatient clinics, and facilitation of self-injection skills represent actionable strategies to support sustained treatment engagement. Strengthening the role of IBD nurses within multidisciplinary teams may enhance adherence, reduce avoidable discontinuations, and ultimately improve long-term disease control.Future prospective studies should evaluate the effectiveness of standardized nursing-led adherence support models. References: 1. Van der Have, M. et al. Inflammatory Bowel Diseases. 2015;21(5):1107–1113. 2. Kane, S. et al. Alimentary Pharmacology 18(2):165–172. 3. Gingold-Belfer, R. et al. Patient Preference and Adherence. 2021;15:1113–1120. 4. Zingone, F. et al. Digestive and Liver Disease. 2022;54(6):773–780. 5. Kawalec, P. et al. Journal of Crohn’s and Colitis. 2017;11(2):161–171. 6. Schultheiss, J. et al. Therap Adv Gastroenterol. 2022;15:1–12. 7. Fiorino, G. et al. Expert Opinion on Biological Therapy. 2021;21(9):1181–1190. Conflict of interest: Marino, Marco: No conflict of interest Magni, Elena: No conflict of interest Simonetta, Grubissa: No conflict of interest Farina, Giuliana: No conflict of interest Martinis, Arianna: No conflict of interest D’Agaro, Paola: No conflict of interest Marangone, Sandra: No conflict of interest Zenarola, Michela: No conflict of interest Rosolen, Valentina: No conflict of interest Morsanutto, Andrea: No conflict of interest Berretti, Debora: No conflict of interest Povoli, Arianna: Takeda, Janssen, Pfizer, Sofar