Colorectal Adenomas in Whites, Hispanics, and Blacks
Colorectal Adenomas in Whites, Hispanics, and Blacks
This hospital-based cross sectional cohort study was conducted at Columbia University Medical Center, a tertiary-care institution located in upper Manhattan, New York City. The surrounding neighbourhood is racially and ethnically diverse and has a large Hispanic population that is predominantly of Dominican and other Caribbean descent.
Data were obtained from the Columbia University Medical Center's electronic medical record systems. All patients ≥50 years undergoing colonoscopy at Columbia University Medical Center's endoscopy unit between March 2006 and June 2010 were identified through the electronic endoscopic database. Examinations in which the colonoscopy was incomplete (i.e. caecum was not reached) were excluded. Patients with a bowel preparation quality deemed poor by the performing endoscopist were excluded from this analysis to minimise the potentially confounding effect of bowel preparation quality. As the goal of this analysis was to restrict the population to those individuals undergoing first-time colonoscopy, we excluded those patients with a prior colonoscopy in the electronic endoscopic database or those with a listed indication of personal history of polyps. We also excluded diagnostic procedures with an indication of overt or occult gastrointestinal blood loss; anaemia; surveillance due to a history of colorectal neoplasia; a history of inflammatory bowel disease; or a syndrome associated with an increased risk of colorectal neoplasia, such as familial adenomatous polyposis or hereditary non-polyposis CRC.
Patient demographic data including gender and age were recorded. Race/ethnicity was self-identified and exported from the electronic medical record, which includes an optional field with this information. The medical record allows entry for only one race/ethnicity category for each individual; this study was limited to those subjects identified as white, Hispanic or black. Patients whose race/ethnicity was not listed in the medical record were excluded from this analysis. All histology reports for colonoscopy cases performed with polypectomy were reviewed. Only those procedures with polyps confirmed to be adenomatous were eligible. The corresponding colonoscopy reports were individually reviewed to obtain data pertaining to adenoma size, number and location. If multiple polyps were submitted in one fixative jar for histological review and adenomatous tissue was identified, this was counted conservatively as one adenoma. Adenoma size was obtained from the endoscopy report or in those few cases in which the size was not specified, the histology report was used to approximate size. The location of each adenoma was documented as proximal or distal: proximal location was defined as those polyps found proximal to the splenic flexure and distal lesions included polyps in the descending colon, sigmoid colon and rectum. Advanced adenomas were defined as those adenomas ≥10 mm in greatest diameter or exhibiting advanced histology such as villous, tubulovillous or high grade dysplasia.
We compared the prevalence of adenomas in whites, Hispanics and in blacks, stratifying by age and gender. This was measured as prevalence of subjects with ≥1 adenoma as well as the rate of adenomas as defined by the total number of adenomas divided by the total number of patients. We used the chi square and Fisher exact tests to compare proportions, and the student's t test to compare continuous variables. We used multivariate Poisson regression to identify factors independently associated with adenoma rates and logistic regression to determine variables independently associated with the presence of advanced adenomas. We determined a priori that the following covariates would be included in the multivariate analyses: patient age and gender, and family history of colorectal neoplasia. As socioeconomic status (SES) and trainee participation may be potential confounders in the association between race and adenoma rates, we used type of insurance as a surrogate for SES and adjusted the analyses by insurance status (Medicaid vs. other), as well as participation of a trainee.
Statistical calculations were performed using sas version 9.2 (Cary, NC, USA). The institutional review board of Columbia University Medical Center approved this study. The requirement of informed consent was waived since no patient contact was required and due to the retrospective nature of this analysis.
Materials and Methods
This hospital-based cross sectional cohort study was conducted at Columbia University Medical Center, a tertiary-care institution located in upper Manhattan, New York City. The surrounding neighbourhood is racially and ethnically diverse and has a large Hispanic population that is predominantly of Dominican and other Caribbean descent.
Record Abstraction
Data were obtained from the Columbia University Medical Center's electronic medical record systems. All patients ≥50 years undergoing colonoscopy at Columbia University Medical Center's endoscopy unit between March 2006 and June 2010 were identified through the electronic endoscopic database. Examinations in which the colonoscopy was incomplete (i.e. caecum was not reached) were excluded. Patients with a bowel preparation quality deemed poor by the performing endoscopist were excluded from this analysis to minimise the potentially confounding effect of bowel preparation quality. As the goal of this analysis was to restrict the population to those individuals undergoing first-time colonoscopy, we excluded those patients with a prior colonoscopy in the electronic endoscopic database or those with a listed indication of personal history of polyps. We also excluded diagnostic procedures with an indication of overt or occult gastrointestinal blood loss; anaemia; surveillance due to a history of colorectal neoplasia; a history of inflammatory bowel disease; or a syndrome associated with an increased risk of colorectal neoplasia, such as familial adenomatous polyposis or hereditary non-polyposis CRC.
Patient demographic data including gender and age were recorded. Race/ethnicity was self-identified and exported from the electronic medical record, which includes an optional field with this information. The medical record allows entry for only one race/ethnicity category for each individual; this study was limited to those subjects identified as white, Hispanic or black. Patients whose race/ethnicity was not listed in the medical record were excluded from this analysis. All histology reports for colonoscopy cases performed with polypectomy were reviewed. Only those procedures with polyps confirmed to be adenomatous were eligible. The corresponding colonoscopy reports were individually reviewed to obtain data pertaining to adenoma size, number and location. If multiple polyps were submitted in one fixative jar for histological review and adenomatous tissue was identified, this was counted conservatively as one adenoma. Adenoma size was obtained from the endoscopy report or in those few cases in which the size was not specified, the histology report was used to approximate size. The location of each adenoma was documented as proximal or distal: proximal location was defined as those polyps found proximal to the splenic flexure and distal lesions included polyps in the descending colon, sigmoid colon and rectum. Advanced adenomas were defined as those adenomas ≥10 mm in greatest diameter or exhibiting advanced histology such as villous, tubulovillous or high grade dysplasia.
Statistical Analysis
We compared the prevalence of adenomas in whites, Hispanics and in blacks, stratifying by age and gender. This was measured as prevalence of subjects with ≥1 adenoma as well as the rate of adenomas as defined by the total number of adenomas divided by the total number of patients. We used the chi square and Fisher exact tests to compare proportions, and the student's t test to compare continuous variables. We used multivariate Poisson regression to identify factors independently associated with adenoma rates and logistic regression to determine variables independently associated with the presence of advanced adenomas. We determined a priori that the following covariates would be included in the multivariate analyses: patient age and gender, and family history of colorectal neoplasia. As socioeconomic status (SES) and trainee participation may be potential confounders in the association between race and adenoma rates, we used type of insurance as a surrogate for SES and adjusted the analyses by insurance status (Medicaid vs. other), as well as participation of a trainee.
Statistical calculations were performed using sas version 9.2 (Cary, NC, USA). The institutional review board of Columbia University Medical Center approved this study. The requirement of informed consent was waived since no patient contact was required and due to the retrospective nature of this analysis.
