Postoperative Complications Associated with Advanced Therapies in Inflammatory Bowel Disease: A Systematic Review and Meta-analysis

Whether preoperative advanced therapy increases postoperative complications in inflammatory bowel disease (IBD) is contested. We conducted a cross-class systematic review distinguishing crude from confounding-adjusted estimates. Five databases were searched to May 2026 for studies of patients with IBD undergoing abdominal surgery. Random-effects meta-analysis estimated comparative odds ratios (ORs) with 95% confidence intervals (CIs) versus unexposed patients across 13 pre-specified outcomes. Confounding-adjusted estimates were pooled separately by inverse-variance, contrasted with crude, meta-regressed on adjustment quality, and rated by GRADE. Ninety-four publications were included. Across the pooled comparisons, advanced therapies were not associated with a uniform excess of postoperative complications; an isolated deep vein thrombosis signal (OR 2.62) most plausibly reflects disease-severity confounding. Crude anti-tumour necrosis factor (anti-TNF) exposure was associated with higher overall complications (OR 1.14, 95% CI 1.02–1.28) and, most reproducibly, intra-abdominal abscess (1.18, 1.01–1.39; 1.34 good-quality); infliximab with sepsis (2.38, 1.30–4.38). Infectious complications, SSI and anastomotic leak were non-significant, and signals were confined to Crohn's disease. After confounding adjustment, anti-TNF odds remained elevated (overall 1.53, 1.12–2.08, k = 18; infectious 1.51, 1.18–1.92) but were heterogeneous, attenuated with adjustment depth to non-significance in the most-adjusted stratum, and null in the only study confirming exposure by measured serum drug levels rather than a preoperative calendar window (infection 1.05). Vedolizumab showed no complication increase but higher readmission (1.70) and reoperation (1.65), consistent with channelling bias. Although there was a signal for association of advanced-therapy with certain complications, the signal is small, heterogeneous, of very low certainty, and absent in drug-level-confirmed evidence. These data are not robust evidence of independent harm and do not justify routine preoperative discontinuation or delay of necessary surgery. This systematic review was prospectively registered with the International Prospective Register of Systematic Reviews (PROSPERO; CRD420261323118).