A multi-center and retrospective analysis of missed diagnosis of colorectal polyps

Objective To study the missed diagnosis of colorectal polyps during colonoscopy and its risk factors. Methods Data of 655 patients who underwent repeated colonoscopy in 3 months (90 days) were analyzed in three endoscopy centers in Shenzhen. Miss rates of polyps and patients were calculated. Logistic regression analysis was used to identify the suspected risk factors associated with the miss rate including gender, age, symptoms of patient and number, shape, location of polyps. Results A total of 459 polyps(20.47%, 459/2 242) in 224 patients(34.20%, 204/655) were missed in overall 1 783 polyps within 655 patients. The patient miss rate increased with the polyp count increasing from 1 to 4, but with no significant differences. Polyp count of more than 5 was the independent risk factor for patient miss rate during colonoscopy(OR=4.98, P=0.00). Polyps in males were easier to be missed than those in females (OR=1.76, P=0.00). Size less than 5 mm was the independent risk factor for missed diagnosis during colonoscopy(OR=2.94, P=0.00). The flat type(YamadaⅠ, Ⅱ) was also the independent risk factor(OR=2.72, P=0.01; OR=3.23, P=0.00 respectively). Conclusion The miss rate of polyps is related to gender, basic polyp count, the size and shape of polyp. Male with multiple polyps and polyps with flat type and small size tend to be missed. Key words: Colorectal polyps; Colonscopy; Miss rates