Polyp prevalence at colonoscopy among Nigerians: A prospective observational study

This study was aimed at identifying the prevalence, distribution, and clinicopathologic characteristic of colonic polyps among Nigerians undergoing colonoscopy at the Obafemi Awolowo University Teaching Hospitals complex, Ile-Ife, Nigeria. We also determined the polyp detection rate (PDR), polyps per colonoscopy (PPC) and adenoma detection rate (ADR).

This is a prospective study of all colonoscopy examinations performed at the endoscopy unit of our hospital from January, 2007 to December 2013. The patient demographics, indications for colonoscopy, colonoscopic findings, number of the polyps, their sizes, possible risk factors in the individual case histories, and histopathological characteristics of the polyps.

During the study period, a total of 415 patients met the inclusion criteria and only 67 out of these had colonic polyps. The overall PDR was 16.1%. The age ranged was 2-87 years with a median of 57 years. Forty-three (64.2%) patients were 50 years or above and there were 40 (59.7%) males. Thirty-three (49.3%) patients were referred as a result of lower gastrointestinal bleeding, 14 (20.9%) for colorectal cancer (CRC) and 13 (19.4%) for routine screening. Thirty-nine (58.2%) patients had the polyps at the rectosigmoid region of the colon, 17 (25.4%) had the polyps located proximal to sigmoid colon and 11 (16.4%) patients had multiple polyps involving both segments. Adenomatous polyps was the most common (28 [47.5%]) histopathological finding of which two patients had adenomatous polyposis. Other findings include inflammatory polyps in 17 (18.8%) patients, 5 (8.5%) patients each had hyperplastic and malignant polyps, while 4 (6.8%) patients had juvenile polyps. The ADR was 6.8 and the PPC was 0.2. Statistically, patients 50 years and older were more likely to have adenomatous and hyperplastic polyps than those younger than this age (P = 0.010).

We conclude that polyps are probably not as rare among black Africans especially when they are above 50 years. Our histopathological finding of adenomatous change in a good proportion of the detected polyps show that they are likely to be associated with CRCs in our compatriots and as such we would recommend a routine screening colonoscopy for Nigerians aged 50 and above.