Table 1.

Characteristics of included randomized controlled trials.

Trials	Country	Colonoscopy indication	Exclusion criteria	N  (total)	Defined age for patients included	Patients allocated to nurse participation	Patients allocated to colonoscopist alone
Lee et al., 2011 [12]	Korea	Asymptomatic average risk individuals for screening colonoscopy	(1) GI bleeding, history of colorectal surgery, IBD, hereditary colorectal cancer, or polyposis syndrome and inability to provide consent; failed intubation and inadequate withdrawal time	791	≥50	407	384
Kim et al., 2012 [13]	Korea	Average risk patients for screening colonoscopy	(1) Symptoms for lower gastrointestinal tract disease; (2) family history of CRC; (3) personal history of CRC, polyps, or IBD; (4) history of a colorectal examination within 5 years or colorectal surgery; (5) failed to reach the cecum	383	≥50	192	191
Aslanian et al., 2013 [14]	USA	Patients for outpatient screening colonoscopy	IBD, hereditary colorectal cancer syndromes	502	None	253	249