Supplementary Material for: Inflammatory Bowel Disease Patients’ Preferences for Subcutaneous Versus Intravenous Therapies: A Mixed Methods Study

Background Multiple biologics are available to treat inflammatory bowel disease (IBD), which can either be administered subcutaneously (SC) or intravenously (IV). The factors that determine patients’ preferences for SC/IV administration in IBD are largely unknown. This study aims to elucidate how IBD patients trade-off between medications’ route of administration and other medication characteristics, and to understand what drives patients’ preferences. Methods We employed a mixed methods design using data from a prior quantitative conjoint analysis survey and a series of 22 qualitative interviews. We quantitatively assessed individual patients’ preferences for SC or IV medications based on the part-worth utilities derived from the conjoint analysis and identified predictors for these preferences. We used a qualitative analysis to identify key themes surrounding patients’ preferences in the interview data. Results Of 1,077 survey participants, 49% preferred an SC medication every 2 weeks, whereas 51% preferred an IV medication every 8 weeks. More people preferred SC at reduced administration frequencies, whereas less people preferred SC at the expense of lower efficacy or higher side-effects rates. Prior experience with SC/IV was the strongest predictor for patients’ preferences. Qualitatively, we obtained in-depth insights in the perceived advantages and disadvantages of SC and IV medications and in patients’ preconceived ideas. Conclusion While prior SC/IV exposure was a strong predictor for SC/IV preferences, patients’ preferences largely are determined by a variety of other personal factors. The themes we identified could help guide clinicians when discussing therapeutic options with their patients and support shared decision making.