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

Table 1 The summarized characteristics of the included studies

Included studies	Study design	IBD phenotypes	Country	Median disease duration(yr)	PSC (n, %)	Family history of CRC (n, %)	Extensive colitis (n, %)	Median follow-up time (yr)	The risk of various grades of colorectal neoplasia (PIPs vs nonPIPs)	Conclusion
Jong MEd 2019[21]	Cohort Study	UC, CD, UNCLASSIFIED IBD	Netherlands	≥ 8.0	27 (5.2%)	74 (14.3%)	345 (66.5%)	21.6 years in PIPs, 22.9 yr in nonPIPs	CRN 36/154 vs 65/365 (aHR = 1.08, 95%CI: 0.66-1.75a); ACRN 9/154 vs 10/365 (aHR = 1.38, 95%CI: 0.52-3.68b); CRC 6/154 vs 7/365	PIPs did not increase the risk of CRN, ACRN or CRC
Mahmoud R 2019[15]	Cohort Study	UC, CD, UNCLASSIFIED IBD	NetherlandsAmerica	≥ 8.0	234 (14.8%)	93 (5.9%)	1275 (80.6%)	5.4 years in PIPs, 4.5 years in nonPIPs	CRN 64/462 vs 124/1120 (aHR = 1.25, 95%CI: 0.88-1.77c); ACRN 17/462 vs 24/1120 (aHR = 1.17, 95%CI: 0.59-2.31d)	PIPs did not increase the risk of CRN or ACRN
Xu W 2020[22]	Cohort Study	UC	China	6.0	10 (4.1%)	NR	116 (47.2%)	13.0	ACRN 11/57 vs 8/189 (aOR = 5.46, 95%CI: 1.69-17.638e)	PIPs increased the risk of ACRN
Choi C-HR 2017[14]	Cohort Study	UC	United Kingdom	≥ 8.0	42 (4.3%)	48 (4.9%)	987 (100%)	13.0	CRN 66/447 vs 31/540 (aHR = 1.20, 95%CI: 0.80-1.80f)	PIPs did not increase the risk of CRC
Jegadeesan R 2016[20]	Case-Control Study	UC	American	12.5	47 (10.1%)	65 (13.1%)	457 (97.9%)	3.0	CRN 32/138 vs 79/329	PIPs did not increase the risk of CRN
Lutgens M 2015[19]	Case-Control Study	UC, CD, UNCLASSIFIED IBD	Netherlands Belgium	NR	30 (5.7%)	33 (6.2%)	349 (65.7%)	NR	CRC 126/260 vs 62/270 (aHR = 2.30, 95%CI: 1.20-4.10g)	PIPs increased the risk of CRC
Baars JE 2011[13]	Case-Control Study	UC, CD, UNCLASSIFIED IBD	Netherlands	9.0	22 (4.3%)	34 (6.6%)	156 (30.4%)	15.5	CRC 71/147 vs 68/366 (aRR = 1.92, 95%CI: 1.28-2.88h)	PIPs increased the risk of CRC
Velayos FS 2006[12]	Case-Control Study	UC	American	17.0	50 (13.3%)	24 (6.4%)	318 (84.6%)	NR	CRC 105/184 vs 83/192 (aOR = 2.50, 95%CI: 1.40-4.60i)	PIPs increased the risk of CRC
Rutter MD 2004[18]	Case-Control Study	UC	United Kingdom	22.0	NR	NR	204 (100%)	NR	CRN 42/95 vs 26/109 (aOR = 2.29, 95%CI: 1.28-4.11j)	PIPs increased the risk of CRN

^aAdjusted factors: IBD type, sex, concomitant PSC, age at IBD diagnosis, maximum disease extent, medication use, family history of CRC, and the mean inflammation score.

^bAdjusted factors: concomitant PSC, and the mean inflammation score.

^cStudy did not report.

^dThirty-eight patients (including 1 ACRN) were excluded due to missing values.

^eAdjusted factors: colorectal stricture, the presence of PIPs, age at IBD diagnosis, disease duration, and concomitant PSC.

^fAdjusted factors: patient’s age, average number of biopsies, surveillance interval, and colonoscopy type (i.e., white-light or chromoendoscopy).

^gAdjusted factors: IBD type, concomitant PSC, microscopic disease extent, and the presence of PIPs.

^hAdjusted factors: age at IBD diagnosis, sex, duration of PSC, disease duration, disease extent at onset, and the presence of PIPs.

ⁱAdjusted factors: age at IBD diagnosis, and disease duration.

^jAdjusted factors: backwash ileitis, shortened colon, tubular colon, scarring, segment of severe inflammation, normal colonic appearance, the presence of PIPs, and colonic stricture. IBD: Inflammatory bowel disease; PSC: Primary sclerosing cholangitis; CRC: Colorectal cancer; PIPs: Post-inflammatory polyps; UC: Ulcerative colitis; CD: Crohn’s disease; UNCLASSIFIED IBD: Unclassified inflammatory bowel disease; CRN: Colorectal neoplasia; ACRN: Advanced colorectal neoplasia; NR: Not reported.