Patients with inflammatory bowel disease and post-inflammatory polyps have an increased risk of colorectal neoplasia: A meta-analysis

BACKGROUND Longstanding intestinal inflammation increases the risk of colorectal neoplasia in patients with inflammatory bowel disease (IBD). Accurately predicting the risk of colorectal neoplasia in the early stage is still challenging. Therefore, identifying visible warning markers of colorectal neoplasia in IBD patients is the focus of the current research. Post-inflammatory polyps (PIPs) are visible markers of severe inflammation under endoscopy. To date, there is controversy regarding the necessity of strengthened surveillance strategies for IBD patients with PIPs. AIM To determine whether IBD patients with PIPs carryan increased risk of colorectal neoplasia. METHODS Researchers searched the following databases up to July 31, 2021: MEDLINE (PubMed), MEDLINE (Ovid), EMBASE, Cochrane Library, China National Knowledge Infrastructure, Wan-Fang Data, China Science and Technology Journal Database and Chinese BioMedical Literature Database. Cohort and case-control studies that compared the risk of colorectal neoplasia between IBD patients with or without PIPs and published in English or Chinese were included. Methodological quality was assessed using the Risk of Bias in Nonrandomized Studies-of Interventions assessment tool. The outcomes of interest were the rates of various grades of colorectal neoplasia. The pooled risk ratio (RR) and 95% confidence interval (95%CI) were calculated using the random-effects model. Begg's test and Egger's test were used to calculate the publication bias. Sensitivity and subgroup analyses were performed to verify the robustness of the results. The Grading of Recommendations, Assessment, Development and Evaluation approach was used to assess the overall quality of evidence supporting the outcomes of interest. RESULTS Nine studies involving 5424 IBD patients (1944 with PIPs vs 3480 without PIPs) were included. The overall bias in each included study ranged from moderate to serious. Compared with nonconcurrent PIPs, patients with PIPs had a higher risk of colorectal neoplasia (RR = 1.74, 95%CI: 1.35-2.24, P < 0.001, I-2 = 81.4%; aHR = 1.31, 95%CI: 1.01-1.70, P = 0.04, I-2 = 26.2%; aOR = 2.62, 95%CI: 1.77-3.88, P < 0.001, I-2 = 0%), advanced colorectal neoplasia (RR = 2.07, 95%CI: 1.49-2.87, P < 0.001, I-2 = 77.4%; aHR = 1.63, 95%CI: 1.05-2.53, P = 0.03, I-2 = 10.1%) and colorectal cancer (RR = 1.93, 95%CI: 1.32-2.82, P = 0.001, I-2 = 83.0%). Publication bias was not observed in Begg's test or Egger's test. Sensitivity and subgroup analyses showed that the results are robust. The overall quality of evidence was assessed as moderate to low. CONCLUSION IBD patients with PIPs may have an increased incidence of colorectal neoplasia.