The Study About The Associations Between Colonic Environment With Colorectal Polyps

Objective: The study was designed to test the associations between colonic environment with colorectal polyps.Methods: We retrospectively collected 2994 patients undergoing colonoscopy from Endoscopy Department of the Second Afiliated Hospital of Nanchang University,between June 1,2015 to May 31,2016,and divided them into case group and control group.The control population consisted of all patients undergoing colonoscopy with normal colonic mucosa on their endoscopy.The case population was consisted of all patients undergoing colonoscopy and diagnosing any of the following diseases by Histopathology and Endoscopy: active colitis,IBD,infective colitis,ischemic colitis,diverticular disease and melanosis coli.Among those,there are 1019 patients with colonic polyps.Using Student's t-test to compare the age differences and using odds ratios and their 95% confidence intervals to compare varying gender and age distributions between case and control group.The associations between colonic polyps and the two groups were also expressed as odds ratios and their 95% confidence intervals,using multivariate logistic regression analyses to adjust for the confounding influence of gender and age.Results:Analysis of initial symptoms for colonoscopy:In the 2994 patients,the initial symptoms of abdominal pain(29.8%)is the most,the symptoms of diarrhea(21.5%),the multiple symptom(19.6%),the symptoms of hematochezia(13.3%)and constipation(10.6%)were followed successively.Analysis of the basic situation of colonic polyps:1.The location analysis of colon polyps: In the 1019 patients with colonic polyps,the colorectal polyps were the most in the sigmoid colon(32.4%),followed by the rectum(19.3%)and the ascending colon(13.1%).2.The pathological type analysis of colon polyps:In the 1019 patients with colonic polyps,the top four pathological type population of polyps in declining order were tubular adenoma(47.4%),inflammatory polyp(29.8%),hyperplastic polyp(10.4%)and mixed adenoma(8.0%).Analysis of influencing factors in different diagnostic groups:1.Age analysis: The mean age of all the patients were 61.7±8.7.Compared with the normal colon,the patients with active colitis,IBD and infective colitis were associated with young age(all P < 0.05,OR < 1)and diverticular disease and melanosis coli were associated with advanced age(all P<0.05,OR>1).The patients with ischemic colitis had no associations with age.2.Gender analysis:Compared with the normal colon,the patients with active colitis,IBD,diverticular disease and melanosis coli were associated with gender(all P<0.05).The patients with infective colitis and ischemic colitis had no associations with gender.Analysis of the association between different diagnostic groups and colonic polyps:1.Analysis of the association between different diagnostic groups and the prevalence rate of colonic polyps:The prevalence rate of colonic polyps in normal colon was highest(37%),followed by ischemic colitis and diverticular disease(both were 25%),active colitis(22%),infective colitis(18%),UC(11%),CD(11%),IBD(6%)and melanosis coli(6%).2.Association between chronic colitis and colonic polyps:The patients with active colitis,IBD,UC,infective colitis were negatively associated with the prevalence of colon polyps(all P<0.05,OR<1).Using multivariate logistic regression analyses to adjust for the confounding influence of gender and age,these patients with active colitis,IBD,UC had the same conclusion(all OR<1).Among the patients with CD and ischemic colitis,such consistent conclusion about a negative association with colon polyps did not come to.3.Association between diverticular disease and colonic polyps:The patients with diverticular disease were negatively associated with the prevalence of colon polyps(P<0.05,OR<1).After adjusting the influencing factors,the patients with diverticular disease had the inverse conclusion(OR>1).4.Association between melanosis coli and colonic polyps:The patients with melanosis coli were negatively associated with the prevalence of colon polyps(P<0.05,OR<1).After adjusting the influencing factors,the patients with melanosis coli had the same conclusion(all OR<1).Conclusion:A low prevalence of colon polyps are associated with the environment of chronic inflammatory and diverticular disease of colon.A high prevalence of colon polyps are associated with the environment of melanosis coli.