7 - High Quality Index Colonoscopies Decrease the Risk for Advanced Outcomes at 10-Year Follow-Up Colonoscopy in Low-Risk Patients With No Index Adenomas or Serrated Polyps

Monday, October 24, 2022

9:42 AM – 9:54 AM ET

Location: Hall C2

Presenting Author(s)

JA

Joseph C. Anderson, MD, MHCDS, FACG

Physician
Dartmouth
Hanover, NH

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Award: Outstanding Research Award in the General Endoscopy Category

Joseph C. Anderson, MD¹, William Hisey, MSc¹, Todd Mackenzie, PhD¹, Christina Robinson, MS², Lynn F. Butterly, MD³
¹Dartmouth, Hanover, NH; ²Dartmouth Hitchcock, Lebanon, NH; ³Dartmouth Hitchcock, Hanover, NH

Introduction: The recent US Multi Society Task Force on CRC (USMSTF) guidelines recommend a 10 year follow up for low risk individuals or those without index adenomas or significant serrated polyps (any SSP/TSA/large ( >/= 1 cm) HP). There are few data examining the impact of quality index colonoscopies on the long term risk of advanced outcomes (advanced adenomas, CRC or large ( >/= 1 cm) serrated polyps) in these low risk patients. We used data from the New Hampshire Colonoscopy Registry (NHCR) to examine the impact of the quality of index colonoscopies on the risk of advanced outcomes in these patients at a follow up interval of 10 years or longer after index exam.

Methods: Our sample included those NHCR patients with no adenomas or significant serrated polyps on index exam and who had at least one follow up exam 12 months or longer after the index. Our exposure variable was the quality of the colonoscopy. A high quality exam was defined as a complete exam with an adequate bowel preparation, performed by an endoscopist with an adenoma detection rate of 25 or higher. Our outcome was advanced outcomes on follow up colonoscopy 10 years (120 months) or longer. We performed a logistic regression with time as our exposure variable, adjusting for age, sex, family history of CRC and Body Mass Index (BMI). While our main goal was to examine the outcome at 10 years or longer after index, we also examined outcomes at 12-59 months (NHCR median=59 months) and 60-119 months.

Results: There were14,257 individuals in our sample (41.2% men; average age 56.3 years)with low risk findings, 2304 of whom had follow up at 10 years. The absolute risk for advanced outcomes after 120 months was lower for the high quality index exams (4.1% (38/933)) versus (6.6% (91/1371)); (p=0.007). The adjusted risk for the high quality exam group was also lower (OR=0.60; 95% CI 0.40-0.89). While there was a statistically significant increase in the absolute (Table 1a) risk 120 months or longer of follow for patients with low quality index colonoscopy, there was no significant increase in risk for the patients with high quality index colonoscopy (Table 1b).

Discussion: NHCR data that high quality index colonoscopy provides better protection from interval lesions detected at 10 years or later than low quality exams in individuals with no polyps detected at that index exam. These data support the importance of high quality index exams in the prevention of interval CRC and supports the 10 year interval for normal exams.

Table 1. Absolute risk (and adjusted for 10+ year period) of metachronous advanced outcomes in individuals with ‘normal’ index colonoscopies (no adenomas or significant serrated polyps), by quality of index colonoscopy

1a. Risk for metachronous advanced outcomes at follow up exams 10 years or longer after index exam
		P value	ADJUSTED RISK	P value
LOW QUALITY INDEX COLONOSCOPY (n=1371)	N=91	0.007	1.0	< 0.01
LOW QUALITY INDEX COLONOSCOPY (n=1371)	6.6%		Reference
HIGH QUALITY INDEX COLONOSCOPY (n=933)	N=38		OR=0.60
HIGH QUALITY INDEX COLONOSCOPY (n=933)	4.1%		95% CI 0.40-0.89
1b. Risk for all time periods
	< 60 months	60-119 months	120+ months	P value
LOW QUALITY INDEX COLONOSCOPY (n=6952)	94	169	91	< 0.015
	4.7%	4.7%	6.6%
	1987	3594	1371
HIGH QUALITY INDEX COLONOSCOPY (n=7305)	77	184	38	0.30
	3.6%	4.4%	4.1%
	2132	4240	933

Table: Advanced outcomes: advanced adenomas, CRC or large (>/= 1 cm) serrated polyps
A high quality exam was defined as a complete exam with an adequate bowel preparation, performed by an endoscopist with an adenoma detection rate of 25 or higher.

Disclosures:

Joseph Anderson indicated no relevant financial relationships.

William Hisey: Exact Sciences – Grant/Research Support.

Todd Mackenzie indicated no relevant financial relationships.

Christina Robinson: Exact Science – Grant/Research Support.

Lynn Butterly: Exact Sciences – Grant/Research Support.

Joseph C. Anderson, MD¹, William Hisey, MSc¹, Todd Mackenzie, PhD¹, Christina Robinson, MS², Lynn F. Butterly, MD³, 7, High Quality Index Colonoscopies Decrease the Risk for Advanced Outcomes at 10-Year Follow-Up Colonoscopy in Low-Risk Patients With No Index Adenomas or Serrated Polyps, ACG 2022 Annual Scientific Meeting Abstracts. Charlotte, NC: American College of Gastroenterology.