Background/Aims: One complication of restorative proctocolectomy with ileo-anal pouch anastomosis is fistula formation in the pouch. Fistulas can be associated with significant morbidity and pouch failure. We conducted a systematic review with meta- analysis to try and understand the prevalence of pouch fistulas in patients with ulcerative colitis following restorative proctocolectomy. Methods: The Embase, Embase Classic, and PubMed databases were searched between January 1979 and April 2022. Studies were included if there were cross-sectional, case-controlled, population-based or cohort studies reporting on prevalence of pouch fistulas in ulcerative colitis. Studies had to report the number of patients with pouch fistulas using either clinical, endoscopic, or radiological diagnosis in an adult population. Results: Thirty-three studies screened met the inclusion criteria. The pooled prevalence of developing at least 1 fistula was 0.05 (95% confidence interval [CI], 0.04–0.07). The pooled prevalence of pouch failure in patients with pouch fistula was found to be 0.24 (95% CI, 0.19–0.30). The pooled prevalence of developing a pouch fistula at 3 years, 5 years and more than 5 years was 0.04 (95% CI, 0.02–0.07), 0.05 (95% CI, 0.02–0.07), and 0.05 (95% CI, 0.02–0.10), respectively. Conclusions This is the first systematic review and meta-analysis to report the prevalence of pouch fistula. It also provides a pooled prevalence of pouch failure in these patients. These results can help to shape future guidelines, power future studies, and help counsel patients.

Background/Aims: One complication of restorative proctocolectomy with ileo-anal pouch anastomosis is fistula formation in the pouch. Fistulas can be associated with significant morbidity and pouch failure. We conducted a systematic review with meta- analysis to try and understand the prevalence of pouch fistulas in patients with ulcerative colitis following restorative proctocolectomy. Methods: The Embase, Embase Classic, and PubMed databases were searched between January 1979 and April 2022. Studies were included if there were cross-sectional, case-controlled, population-based or cohort studies reporting on prevalence of pouch fistulas in ulcerative colitis. Studies had to report the number of patients with pouch fistulas using either clinical, endoscopic, or radiological diagnosis in an adult population. Results: Thirty-three studies screened met the inclusion criteria. The pooled prevalence of developing at least 1 fistula was 0.05 (95% confidence interval [CI], 0.04–0.07). The pooled prevalence of pouch failure in patients with pouch fistula was found to be 0.24 (95% CI, 0.19–0.30). The pooled prevalence of developing a pouch fistula at 3 years, 5 years and more than 5 years was 0.04 (95% CI, 0.02–0.07), 0.05 (95% CI, 0.02–0.07), and 0.05 (95% CI, 0.02–0.10), respectively. Conclusions This is the first systematic review and meta-analysis to report the prevalence of pouch fistula. It also provides a pooled prevalence of pouch failure in these patients. These results can help to shape future guidelines, power future studies, and help counsel patients.

Background/Aims: One complication of restorative proctocolectomy with ileo-anal pouch anastomosis is fistula formation in the pouch. Fistulas can be associated with significant morbidity and pouch failure. We conducted a systematic review with meta- analysis to try and understand the prevalence of pouch fistulas in patients with ulcerative colitis following restorative proctocolectomy. Methods: The Embase, Embase Classic, and PubMed databases were searched between January 1979 and April 2022. Studies were included if there were cross-sectional, case-controlled, population-based or cohort studies reporting on prevalence of pouch fistulas in ulcerative colitis. Studies had to report the number of patients with pouch fistulas using either clinical, endoscopic, or radiological diagnosis in an adult population. Results: Thirty-three studies screened met the inclusion criteria. The pooled prevalence of developing at least 1 fistula was 0.05 (95% confidence interval [CI], 0.04–0.07). The pooled prevalence of pouch failure in patients with pouch fistula was found to be 0.24 (95% CI, 0.19–0.30). The pooled prevalence of developing a pouch fistula at 3 years, 5 years and more than 5 years was 0.04 (95% CI, 0.02–0.07), 0.05 (95% CI, 0.02–0.07), and 0.05 (95% CI, 0.02–0.10), respectively. Conclusions This is the first systematic review and meta-analysis to report the prevalence of pouch fistula. It also provides a pooled prevalence of pouch failure in these patients. These results can help to shape future guidelines, power future studies, and help counsel patients.

Background/Aims: Assessment of quality of magnetic resonance enterography (MRE) in small bowel Crohn’s disease (CD) activity evaluation has received little attention. We assessed the impact of bowel distention and motion artifact on MRE activity indices in ileal CD. Methods: A cohort of patients who underwent contemporaneous MRE and colonoscopy for ileal CD assessment between 2014 and 2021 at 2 centers were audited. An abdominal radiologist blinded to clinical data reviewed each MRE, graded bowel distention and motion artifact upon a pre-specified 3-point scale and calculated the original magnetic resonance index of activity (MaRIA) and simplified MaRIA (sMaRIA), London index and CD MRE index (CDMI). Ileal endoscopic activity was graded via the Simplified Endoscopy Score for CD (SES-CD). The performance of MRE indices in discriminating active disease (SES-CD ≥3) stratified by MRE quality was measured by receiver operator characteristic analyses. Results: One hundred and thirty-seven patients had MRE and colonoscopy within a median of 16 days (range, 0–30 days) with 63 (46%) exhibiting active disease (SES-CD ≥3). Forty-four MREs (32%) were deemed low quality due to motion artifact and/or moderate to poor distention. Low-quality MREs demonstrated reduced discriminative performance between ileal SES-CD ≥3 and MRE indices (MaRIA 0.838 vs. 0.634, sMaRIA 0.834 vs. 0.527, CDMI 0.850 vs. 0.595, London 0.748 vs. 0.511, P<0.05 for all). Individually the presence of any motion artifact markedly impacted the discriminative performance (e.g., sMaRIA area under the curve 0.544 vs. 0.814, P<0.05). Conclusions Image quality parameters can significantly impact MRE disease activity interpretation. Quality metrics should be reported, enabling cautious interpretation in lower-quality studies.