Background and aimsPatient-reported outcomes (PROs) are pivotal in assessing treatment efficacy and estimating the burden of inflammatory bowel diseases (IBD). We investigated PROs at the time of IBD diagnosis. MethodsThe Short Inflammatory Bowel Disease Questionnaire (SIBDQ), IBD-Disability Index (IBD-DI), Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F), and disease activity-related PROs were assessed in the Copenhagen IBD Inception Cohort, a prospective, population-based cohort of patients newly diagnosed with IBD between May 2021 and May 2023. ResultsA total of 203 UC and 116 CD patients were recruited. At diagnosis, 160 (78.8%) and 99 (85.3%) patients with UC and CD, respectively, reported moderate-to-severe impairment in at least one PRO (p=0.18), with 89 (43.8%) and 74 (63.8%), respectively, reporting moderate-to-severe impairment in at least two PROs (p<0.01). Being female, the disease extent of UC, and extraintestinal manifestations were associated with impaired PROs. There were no differences found according to CD phenotype. FACIT-F, IBD-DI, and SIBDQ scores showed weak, but significant, correlations with the Mayo Endoscopic Score in UC, and the FACIT-F score with C-reactive protein (CRP). In CD, SIBDQ, IBD-DI, and FACIT-F correlated moderately with CRP and fecal calprotectin, but not with the endoscopic severity of CD. None of the PROs correlated with iron, ferritin, or vitamin D levels. Among the most prevalent symptoms reported were fatigue, abdominal pain, urgency, and passing of blood in both CD and UC. ConclusionWe found a substantial patient-reported disease burden in newly diagnosed IBD, underscoring the importance of vigilant PRO monitoring in clinical practice. FundingThis study was funded by an unrestricted grant from the Novo Nordisk Fonden.