. Author manuscript; available in PMC: 2014 Sep 1.

Published in final edited form as: Am J Gastroenterol. 2014 Jan 7;109(3):417–426. doi: 10.1038/ajg.2013.442

Table 5.

Prior Studies of Withdrawal Time (WT) Correlation to Adenoma Detection Rate (ADR), Polyp Detection Rate (PDR), and / or Serrated Polyp Detection Rate (SDR)

Author/Date	N and Setting	Withdrawal Time Measurement	Patient Characteristics	Endoscopist Characteristics	Outcome/Comments
De Wijkerslooth et al. 2013²⁹	1354 patients, 5 endoscopists in Norway	WT for all exams but had to be at least 6 minutes	Age, Gender and bowel preparation	Experience (years) and intubation time	Longer WT associated with higher proximal SDR
Lee TJ et al. 2013²⁵	31,088 colonoscopies in England	Endoscopist mean WT for negative colonoscopies	Age, gender, smoking status, alcohol use, bowel prep	None	Increases in mean WT up to 10 minutes associated with increased ADR, mainly small or right sided adenomas.
Adler et al. 2012³²	12,134 screening colonoscopies; Germany	Endoscopist mean WT for negative colonoscopies	Age, gender, NSAID use, bowel prep	Volume/year, intubation rate, CME	For WT 6–11 minutes no correlation with ADR; high mean WT (8.7 minutes) in study.
Liang et al. 2012³⁴	18003 exams; by 6 colorectal surgeons; US	WT for normal exams	Age and Gender	None	WT correlated with SDR
Moritz et al. 2012³³	4429 colonoscopies; Norway	Endoscopist median WT for negative colonoscopies; <6 min. vs ≥6 min.	Age, Gender	Volume	WT with 6 minute threshold not a strong predictor of PDR
Lee RH et al. 2011³⁵	752 colonoscopies; US	Endoscopist mean WT not including time for polypectomy or	Age, gender	Age	No significant relationship between WT and ADR; study not powered to detect small differences in WT
Lee TJ et al. 2011³¹	36,460 colonoscopies; UK	Endoscopist mean WT for negative colonoscopies	Age	Sedation practice	Mean WT correlated with higher ADR
Benson et al. 2010¹⁵	550 screening colonoscopies; US	Endoscopist mean WT for negative colonoscopies	Age, gender	Years in practice	Significant 5-fold increase in ADR with WT >6 minutes vs. < 6 minutes
Gellad et al. 2010⁵⁴	304 follow-up colonoscopies in patients with normal baseline colonoscopies; US VA Medical Centers	WT= procedure time minus insertion time for negative colonoscopies	Gender, Age, Family History, CRC, Smoking, ETOH, BMI, diabetes, NSAID use	None	No correlation with ADR seen after center with fastest WT removed; high baseline WT (mean >12 minutes); possible threshold in NWT with no further increase in ADR
Overholt et al. 2010²⁴	15,955 colonoscopies; US	Endoscopist mean WT for negative colonoscopies	Age, gender	Age	Statistically significant increase in PDR and ADR for WT ≥6 minutes vs. < 6 minutes
Taber et al. 2010⁵²	1405 colonoscopies pre and 1387 post intervention; US	Endoscopist mean WT for negative colonoscopies	Age, gender, procedure indication	None	No difference in PDR for endoscopists with mean WT >10 minutes vs ≤ 10 minutes
Barclay et al. 2008²³	2053 colonoscopies; US	Endoscopist mean WT for negative colonoscopies	None	None	WT of 8 minutes or more correlated with higher ADR
Sawhney et al. 2008⁵¹	23,910 colonoscopies; US	WT for negative colonoscopies recorded as < 7 minutes or ≥7 minutes	Age, gender	Experience performing endoscopy	No increase in PDR with increased compliance with 7 minute min. WT;
Barclay et al. 2006¹⁴	7882 colonoscopies; US	Endoscopist mean WT for negative colonoscopies	None	None	Endoscopist mean WT > 6 minutes correlated with more adenomas and advanced adenomas
Simmons et al. 2006²⁷	10,955 colonoscopies; US	Endoscopist mean WT for negative colonoscopies	Age, gender	None	Longer WT correlated with PDR; recommended minimum WT ≥7 minutes
Sanchez et al. 2004¹⁸	10,159 colonoscopies; 4312 with polyps; US	Endoscopist mean Procedure Time for negative colonoscopies	Age, Gender	None	Longer procedure time correlated with PDR

ADR= Adenoma detection rate, ASC= Ambulatory Surgery Center, PDR= Polyp detection rate, SDR = Serrated Polyp Detection Rate, WT= Withdrawal time