Background Acute severe ulcerative colitis (ASUC) poses challenges to patient management owing to its high incidence and surgical rate. This study aimed to identify predictors of colectomy in patients with ASUC.

Methods PubMed and Web of Science were systematically searched up to December 2022 to identify studies on predictors of colectomy in patients diagnosed with ASUC based on the Truelove and Witts criteria or physician assessment. The primary outcome was colectomy within a 1-year period, while the secondary outcome was colectomy occurring over a longer follow-up duration. The quality of each study was assessed using the Newcastle-Ottawa Scale. A tabular qualitative synthesis was executed. Random-effects meta-analyses were conducted using odds ratios (OR) and 95% confidence intervals (CI). Statistical heterogeneity among studies was analyzed using Cochran’s Q test and the I² statistic. This study was registered in the International Prospective Register of Systematic Reviews (CRD42022361905).

Results Thirty-six studies were included in the systematic review. One and 35 studies were rated as moderate and high quality, respectively. The reported variables were categorized into biomarkers, auxiliary examination findings, demographic and clinical characteristics, and drug factors. Through meta-analysis, albumin (0.39 [0.26–0.59] per 1 g/dL increment), high C-reactive protein level (2.63 [1.53–4.52]), high erythrocyte sedimentation rate level (2.92 [1.39–6.14]), low hemoglobin level (2.08 [1.07–4.07]), fulfilling the Oxford criteria (4.42 [2.85–6.84]), extensive colitis (1.85 [1.24–2.78]), the older adults (2.18 [1.14–4.15]), newly diagnosed colitis (1.97 [1.00–3.90]), previous steroids (1.75 [1.23–2.50]) or azathioprine (2.25 [1.28–3.96]) use, and sarcopenia (1.90 [1.04–3.45]) were identified as valuable predictors (OR [95% CI]) for colectomy within 1 year. The ulcerative colitis endoscopic index of severity (OR [95% CI]: 2.41 [1.72–3.39]) was the only predictor found to predict colectomy over 1 year. No significant heterogeneity was observed among studies for predictors above except for hemoglobin (I²=56.4%, P=0.076).

Conclusions Identifying predictors of colectomy in ASUC is crucial for optimizing personalized management strategies so as to reduce the need for colectomy. Further research of these predictors is warranted to confirm their utility in clinical practice.