The effect of polyp location and patient gender on the presence of dysplasia in colonic polyps

Objective: There is increasing evidence of significant clinical and biological differences between proximal and distal colorectal polyps, as well as possible differences based on patient gender. There is a need to optimize and individualize screening strategies. We studied the potential influence of gender and of polyp location on the presence of dysplasia in colon polyps. Methods: We used a prospective database on adenoma detection to identify patients. The primary outcome was the presence of dysplasia in colonic polyps. Covariates include age, gender, race, lesion size and site, and use of aspirin. Multivariate logistic regression analysis was used to analyze the relationship between the primary outcome and covariates. Results were reported as odds ratios (ORs), 95% confidence intervals (CIs), and P-values. Results: A total of 2,400 patients (50.5% females and 49.5% males) completed colonoscopy for various indications. A total of 3,045 polyps were removed in 1,237 patients. Of those polyps, 54% (n=1,636) were on the right compared with 46% (n=1,409) in the left colon. The proportion of adenomas was significantly greater on the right colon when compared with the left: 69.4% vs. 39.3% (P= <0.0001). Multivariate logistic regression analysis showed that the right colon did have a significant association with dysplasia when controlling for age, gender, polyp size, and use of aspirin (OR=3.1 (95% CI: 2.3-4), P= <0.0001). Female gender was associated with decreased odds of finding dysplasia (OR=0.6 (95% CI: 0.46-0.78), P=0.03). Conclusion: Patient characteristics (male gender) as well procedure findings (increase polyp size and right-sided lesions) are associated with increased odds of dysplasia.