P0349 The societal burden of perianal fistulizing Crohn’s disease: high costs driven by absenteeism in a prospective nationwide Dutch cohort study

Abstract Background Perianal fistulizing Crohn’s disease (pCD) is associated with higher direct medical costs compared to luminal CD. Data on indirect costs, including productivity losses, are scarce, limiting our understanding of the full societal burden of pCD. Therefore, we evaluated the societal impact of active pCD by quantifying both direct and indirect costs and to explore how these costs vary according to disease duration. Methods A prospective study was performed in which patients with active pCD (draining fistula, visible external fistula orifice and/or an active fistula on imaging) were included within 41 hospitals in the Netherlands between September 2022 and March 2023. Follow-up duration was one year. The medical (direct) in-hospital costs, including IBD medication, hospital visits, radiological and endoscopic procedures, and surgical interventions, were extracted from electronic medical records. Out-of-hospital (direct) costs were assessed with an adapted version of the iMTA Medical Consumption Questionnaire (iMCQ). Indirect costs, comprising absenteeism and presenteeism, were measured with the iMTA Productivity Cost Questionnaire (iPCQ). Both were collected at baseline, 3, 6, and 12 months. The Dutch costing manual was used to determine cost prices. Missing data were imputed using multilevel multiple imputation by a lineair mixed model based on predictive mean matching. Costs were presented as mean annual costs per patient in the year 2023. Results A total of 440 patients were included (mean age 40 (SD 13.4); 53% female; median pCD duration 3.2 years [IQR 1.2-7.5], 66% were treated with anti-TNF agents). The mean annual costs per patient were €40.976 (95% confidence interval 37420-44532). Medication costs accounted for €14.954 (13839-16068) of which €14.683 (13567-15800) were attributable to biologicals. Hospital visits were €3.206 (2680-3733). Radiological assessments and endoscopic procedures contributed €400 (357-444) while surgical interventions, including treatment with Darvadstrocel, amounted to €5.421 (3877-6965) per patient per year. Out-of-hospital medical costs (general practitioners, psychosocial workers) averaged €550 (331-769). Annual indirect costs were €16.885 (13186-20585) per patient, comprising absenteeism (€12.975, 9402-16547; and presenteeism (€3.911, 3210-4611). Indirect costs remained stable across pCD duration (Figure 1, 2). Conclusion The total annual costs per patient with active pCD are substantial and remain high independent of disease duration. Costs are primarily driven by biological therapies and productivity loss due to absenteeism. Absenteeism consistently accounts for more than 25% of total costs, underscoring the impact of active pCD on the ability to work and the overall societal burden. Conflict of interest: Ms. Verweij, Merel: No conflict of interest Bak, Michiel: Grant: Unrestricted research grant from Falk Pharma Benelux Other: Speaker fees from AbbVie Heemskerk, Stella: No conflict of interest Post, Richard: No conflict of interest Stassen, Laurents: Grant: Karl Storz GmbH Other: Diagnostic Green USA Buskens, Christianne J.: Grant: C. Buskens has received an unrestricted grant from Boehringer Ingelheim and Roche Personal Fees: C. Buskens has received consultancy fees and/or speaker’s honoraria from Tillotts, Takeda, MSD and Janssen Pronk, Annelies: No conflict of interest Van Der Bilt, Jarmila: No conflict of interest Gecse, Krisztina B.: Grant: Abbvie, Pfizer Inc, Celltrion and Galapagos/Alfasigma Personal Fees: Consultancy fees from AbbVie, ​Galapagos, Gilead, Immunic Therapeutics, Janssen Pharmaceuticals, Pfizer Inc., and Takeda and speaker’s honoraria from Celltrion, Eli Lilly, Janssen Pharmaceuticals, Pfizer Inc. and Takeda. De Boer, Nanne: No conflict of interest Witjes, Caroline: No conflict of interest Fitzpatrick, Claire: No conflict of interest Pierik, Marieke: Grant: TKI, MLDS, Galapagos, Janssen-Cilag, Takeda, Pfizer Other: Financial support to institution for consultancy or lectures: Takeda, Janssen-Cilag, BMS, MSD, Abbvie, Galapagos, Ferring Breukink, Stephanie: No conflict of interest Nissen, Loes: No conflict of interest Verdaasdonk, Emiel: No conflict of interest Gilissen, Lennard: none Bloemen, Johanne: No conflict of interest West, Rachel: No conflict of interest Kortekaas, Robert: No conflict of interest Mares, Wout: No conflict of interest De Jong, Gabie: No conflict of interest Janssen, Sita: No conflict of interest Bloemendaal, Bob: No conflict of interest Sikkema, Marjolein: No conflict of interest Zimmerman, David: No conflict of interest Peeters, Koen: No conflict of interest Van der Meulen - de Jong, Andrea Elisabeth: No conflict of interest van Schaik, Fiona: FDM van Schaik has received consultancy fees from Takeda, Galapagos and AbbVie, speaker’s honoraria from Galapagos, Lilly, AbbVie and Janssen-Cilag B.V., hospitality fees from Ferring and dr. Falk Farma and an unrestricted research grant from Takeda. Richir, Milan: No conflict of interest Dongen, Koen: No conflict of interest Duijvestein, Marjolijn: Grant: Speaking fees from Bristol Meyers Squibb, Takeda, Galapagos, Janssen, Dr. Falk, Advisory board fees from Abbvie, Bristol Meyers Squibb, Celltrion, Galapagos/Alfasigma, Janssen, Takeda Grant/Research support: Pfizer, Bristol Meyers Squibb, Galapagos, Alfasigma, Janssen, Lilly Hoogenboom, Froukje J.: No conflict of interest Visschedijk, Marijn: No conflict of interest Molendijk, Ilse: Advisory board and / or financial compensation from the following companies: Abbvie, Dr. Falk and Johnson & Johnson Van Ruler, Oddeke: No conflict of interest De Vries, Annemarie C.: Grant: Grants, advisory boards: Pfizer, Galapagos, Takeda, Janssen