Abstract Background Psychiatric comorbidity in inflammatory bowel disease (IBD) is increasingly recognized, with evidence suggesting shared etiological pathways between immune-mediated diseases and mental health disorders. Neurodevelopmental disorders, including attention deficit hyperactivity disorder (ADHD) and autism, differ from most psychiatric conditions in that they are of neurodevelopmental origin and typically precede the onset of chronic disease. In other immune-mediated conditions, cooccurring neurodevelopmental disorders have been linked to poorer disease control and greater complication risk. The aim of this study was to estimate the effect of ADHD and autism on the disease activity of IBD in paediatric and young patients. Methods Patients diagnosed with IBD between ages 6-24 years were identified in Danish nationwide registries 1996-2022 using a previously validated algorithm. Cumulative incidences for severe disease activity (advanced therapies, oral corticosteroids, IBD-related surgery and hospitalisation) were estimated and compared between patients with IBD with and without ADHD/autism. Cox regression analysis was used to calculate adjusted hazard ratios (aHR) with 95% confidence intervals (CI) for each of the severe events. Results A total of 785 patients with IBD and ADHD/autism and 6,729 patients with IBD only were included. During follow-up, patients with IBD and ADHD/autism had increased risk for severe disease activity compared to patients with IBD only (Figure 1), and an increased risk of receiving advanced IBD therapies (aHR: 1.2, 95%CI: 1.0-1.3). Specifically, patients with ulcerative colitis and ADHD/autism had an increased risk for colectomy (aHR: 1.4, 95%CI: 1.0-1.8), especially those diagnosed with IBD before 18 years of age (aHR: 1.7, 95%CI: 1.1-2.6). Patients with IBD and ADHD/autism had a lower risk of hospitalisation for IBD (aHR: 0.8, 95%CI: 0.7-0.9), but for the ones with hospitalisations they had longer hospitalisations. Conclusion ADHD and autism were associated with a more severe IBD disease activity in paediatric and young patients as compared to patients with IBD but no autism or ADHD diagnosis. Conflict of interest: Jansson, Sabine: Has received travel support from Ferring Pharmaceuticals and research funding from Takeda Pharma A/s, and Ferring Pharmaceuticals. All unrelated to the work submitted. Wewer, Mads Damsgaard: Novo Nordisk Foundation, grant Bristol Myers Squibb, unrestricted grant Burisch, Johan: Grant: Johnson & Johnson, MSD, Takeda, Tillots Pharma, BMS, Novo Nordisk Personal Fees: Celgene, MSD, Pfizer, AbbVie, Takeda, Tillots Pharma, Samsung Bioepis, BMS, Pharmacosmos, Galapagos, Zealand Pharma, Orion Pharma, Ferring, Johnson & Johnson Fox, Matthew P.: No conflict of interest Benros, Michael E.: No conflict of interest Rask, Charlotte Ulrikka: Grants from Aage og Johanne Louis-Hansen Fond, Novo Nordisk Foundation (via the Best for You project), Lundbeck Foundation. All unrelated to the work submitted. Wewer, Vibeke: Grants from Aage and Johanne Louis-Hansens Fond Malham, Mikkel: No conflict of interest
Jansson et al. (Thu,) studied this question.