Should Adenoma Detection Rates Be Adjusted for Smokers and Obese Adults? Data from the New Hampshire Colonoscopy Registry: 2016 ACG Presidential Poster Award

Abstract

Introduction: Adenoma detection rate (ADR), a quality measure for screening colonoscopies, is associated with protection from interval colorectal cancer (CRC). Currently ADR benchmarks are adjusted for sex only. Obesity and smoking > 20 pack-years were highlighted as important risk factors by the 2009 American College of Gastroenterology CRC Screening Guidelines, but with limited data there are no recommendations to adjust endoscopists' ADR for these factors. We examined the ADR for smokers and obese adults in the New Hampshire Colonoscopy Registry (NHCR).Table 1: Overall and gender specific adenoma detection rates and 95% confidence intervals for patient risk factors among NHCR screening colonoscopies (4/6/2009-9/13/2013))*Methods: The NHCR is a population-based, statewide registry collecting data from endoscopy sites in NH. Prior to colonoscopy, consenting adults complete a questionnaire. Smoking exposure includes current status (never/past/current), # of yrs smoked and # of cigarettes/day, if applicable. We calculated ADR with 95% CI for screening colonoscopies in adults > 50 yrs. The rates were compared by smoking exposure (never vs < 20 pack-years vs > 20 pk-yrs) and BMI (> 30 vs < 30). Results: We analyzed 21,539 screening colonoscopies performed by 77 endoscopists at 20 facilities (4/09 -9/2013). 26% of adults (5423/20,598) had a > 20 pk-yr exposure. 34% (7036/20814) were obese. The ADR for smokers was higher than non- smokers (29.8% vs 21.0%; p < 0.0001). The highest ADR were seen in males with > 20 pk-yrs (35.8%). Obese adults had a significantly higher ADR than non obese adults (26.8% vs 21.8%; p < 0.0001). Conclusion: Among NHCR participants, ADRs for smokers and obese adults are significantly higher than their counterparts without those risks. The difference in ADR between non-smokers and smokers with > 20 pk-yrs was 8.8%, similar to the 10% sex difference in ASGE/ACG benchmarks. Thus, a population of men with a high prevalence of smoking, as observed in Veterans Affairs Medical Centers (72% smokers; Lieberman 2003 JAMA; ADR 37.5% NEJM 2000) might require an ADR or 35% or higher. However, in our sample, despite smokers with > 20 pk-yrs comprising 25% of the NHCR and obese adults comprising 33%, the overall NHCR ADR (23.6%) was consistent with a typical screening population. Endoscopists should be aware of smoking and obesity rates in their practice. Adjusting ADR benchmark goals for these factors, as is currently suggested for sex, may provide optimal protection for some populations where these risks have a high prevalence. However, adjustment for these factors may not be needed for most screening populations.