20.500.12556/DiRROS-25169 Placebo rates in randomised clinical trials of ulcerative colitis an individual patient data meta-analysis Background and aims: We assessed placebo rates and associated factors using individual patient data (IDP) from randomised clinical trials (RCTs) in ulcerative colitis (UC). Methods: We conducted an IPD meta-analysis using Vivli and Yale University Open Data Access data-sharing platforms. Phase 2 and 3 RCTs of advanced biologics in adults with moderate-to-severe UC published since 2010 were included. Pooled placebo rates and 95% CIs were estimated using one-and two-stage meta-analytical approaches. Significant patient-level factors (P < 0·05) were identified using regression analyses. Primary outcomes were clinical response and remission. Results: Data were available for 1703 patients from nine studies. For induction trials, overall placebo response and remission rates were 33% (95% CI 29%–38%) and 9% (95% CI 7%–11%). Overall placebo response and remission rates in maintenance trials were 28% (95% CI 18%–41%) and 14% (95% CI 9%–20%). A lower body mass index reduced odds of placebo response and remission, while higher baseline albumin levels and left-sided (compared to extensive) UC increased the odds of these outcomes. A one-point increase in the Mayo Clinic Score (MCS) and adapted MCS was associated with a 26% and 27% reduction in odds of clinical remission. For induction trials, prior biologic exposure was associated with lower odds of response and remission. Multi-centre trials have lower placebo effects than single-centre trials. Conclusions: These results enable future trials to incorporate design elements that reduce placebo rates as well as a precise benchmark for expected rates in clinical trials that do not include placebo. inflammatory bowel disease placebo effect clinical trials ulcerative colitis kronične vnetne črevesne bolezeni učinek placeba klinične raziskave ulcerozni kolitis true false true Angleški jezik Slovenski jezik Neznano 2026-01-13 08:59:26 2026-01-13 08:59:27 2026-01-14 03:53:35 0000-00-00 00:00:00 2025 0 0 Nasl. z nasl. zaslona; Opis vira z dne 14. 11. 2025; str. 1-13 iss. 10, [article no.] jjaf191 Vol. 19 2025 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 616.3 1876-4479 10.1093/ecco-jcc/jjaf191 257167107 RAZ_Solitano_Virginia_2025.pdf RAZ_Solitano_Virginia_2025.pdf 1 C531E72ED5DC4D145B98AE427A126264 da9786ce2b5e2b318b2dce6c29f41dcb20096052b12ef43fa8d5682c814cc145 f6c3f50c-f055-11f0-94a7-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=37932 https://academic.oup.com/ecco-jcc/article/19/10/jjaf191/8317441 0 03aa140f-f056-11f0-94a7-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=37933 Univerzitetni klinični center Ljubljana 0 0 0