Table 6

 Meta-analyses of studies that have investigated appendicectomy in UC or PSC

I: Appendicectomy rate in patient and control groups: meta-analysis of four studies
StudyPSC (n)UC (n)Control group (n)Comments
(a) van Erpecum4059130197Small groups, reported all appendicectomy—before and after diagnosis.
(b) Mitchell41170170170Did not find low App+ in UC.
(c) Selby2523236280Small PSC group.
(d) Florin902941466Disease specific control groups.
Meta-analysis (a–d)3428302113
App+6162424App data missing for 166 controls and 1 PSC.
p Value (App+: disease v controls)0.12<0.0001; OR 0.29 (CI 0.22 –0.38)OR (CI) of App+ in UC relative to App+ in control group.
II: Appendicectomy v colorectal cancer: meta-analysis of two studies
PSC, primary sclerosing cholangitis; IBD, inflammatory bowel disease; UC, ulcerative colitis; OR, odds ratio; CI, confidence interval; App, appendicectomy; CRC, colorectal cancer.
Meta-analysis (c, d)113530High grade dysplasia not analysed because these data not available in (c).
App+ (CRC)26 (1)28 (3)Prior appendicectomy data missing for 1 PSC-IBD case.
App− (CRC)86 (3)502 (4)
p Value (CRC v App+)1.00.004; OR 14.9 (CI 3.2–70)OR (CI) of colorectal cancer in UC patients with prior appendicectomy relative to UC patients who have not undergone prior appendicectomy.