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Adenoma Detection Rates in 45–49-Year-Old Persons Undergoing Screening Colonoscopy: Analysis From the GIQuIC Registry

Bilal, Mohammad MD1; Holub, Jennifer MPH2; Greenwald, David MD3; Pochapin, Mark B. MD4; Rex, Douglas K. MD5; Shaukat, Aasma MD, MPH4

Author Information
The American Journal of Gastroenterology: May 2022 - Volume 117 - Issue 5 - p 806-808
doi: 10.14309/ajg.0000000000001684



Colorectal cancer (CRC) continues to be the second leading cause of cancer-related deaths in the United States (1). In recent years, there has been a decrease in incidence of CRC overall; however, there has been an increasing incidence of CRC in younger individuals (2). In 2018, the American Cancer Society has made qualified recommendations to begin CRC screening at age 45 years in all average-risk patients (3). Earlier this year, the United States Preventive Services Task Force, the United States Multisociety Task Force, and the American College of Gastroenterology issued recommendations to start CRC screening at the age of 45 years (4–6). Colonoscopy has been shown to reduce the incidence of CRC by detection and removal of precancerous polyps (7). Current benchmarks for the adenoma detection rate (ADR) for screening colonoscopy in men and women 50 years and older are 30% and 20%, for an overall ADR benchmark of 25% (8). The impact of lowering the screening age on endoscopist ADR is not clear. Our aim was to calculate endoscopists' ADRs in 45–49-year-old men and women undergoing screening colonoscopy compared with 50–75-year-old men and women using the GIQuIC registry.


We used the GI Quality Improvement Consortium (GIQuIC) registry for our analysis. This was developed in 2009 as a collaborative, nonprofit scientific organization between the American College of Gastroenterology and the American Society for Gastrointestinal Endoscopy (9). The GIQuIC registry captures procedure information, such as history and physical examination, informed consent, bowel preparation adequacy, American Society of Anesthesiology class, indication, photodocumentation of the cecum, withdrawal time, immediate adverse events, pathology results, and recommended follow-up interval for next colonoscopy.

The GIQuIC's colonoscopy data collection form has a separate question regarding risk assessment and includes selection of “average-risk,” “high-risk,” and “N/A” as options. If the “high-risk” option is selected, then further specification of family history or personal history of colon polyps/carcinoma is required. We focused our analysis to average-risk screening colonoscopies only, from 2014 to 2020 among individuals aged 45–75 years. However, for completeness, we also calculated the ADRs in 45–49-year-old individuals, regardless of family history. Only the first colonoscopy record per patient at each site was included. We included endoscopists who performed at least 30 screening examinations and had less than 5% of pathology information missing. Procedures with screening as the only indication, adequate bowel preparation, and photodocumentation of the cecum were included. We used total withdrawal time as reported in the registry, which includes time taken for inspection and polypectomy (if applicable). We used the 1-way ANOVA test to determine differences between ADRs among 45–49-year-old, 50–54-year-old, and 50–75-year-old patients. The GIQuIC research database is exempt from institutional review board overview as determined by Western Institutional Review Board.


A total of 2,806,539 screening colonoscopies performed by 814 endoscopists across the United States were included in the analysis. In total, 47,213 colonoscopies (1.6%) were performed in patients aged 45–49 years, 1,014,193 (36%) were in 50–54 years, and 2,759,326 were in 50–75 years. The number of screening colonoscopies in patients aged 45–49 years increased over time, especially after 2018 (see Supplementary Table 1, Supplementary Digital Content 1,

The mean ADR in the 45–49-year-old group was 28.6% compared with 31.8% for the 50–54-year-old group (P < 0.001) and 36.3% for the 50–75-year-old group (P < 0.001). The endoscopists mean ADRs for men and women of age 45–49 years were 32.9% and 22.8%, respectively, compared with mean ADRs for men and women of age 50–54 years of 36.9% and 25.5%, respectively (P < 0.0001 for men and P < 0.0001 for women), and 41.5% for men and 30.1% for women of age 50–75 years, respectively (P < 0.001, respectively) (Table 1).

Table 1.:
Comparison of ADR by age group

The overall ADR for patients aged 45–49 years regardless of a family history of CRC was 28.5% (mean ADR in men: 32.8% and mean ADR in women: 22.9%).


We found small differences in the overall ADR for 45–49-year-old patients compared with 50–54-year-old patients undergoing screening colonoscopy but a meaningful difference compared with the entire screening population of 50–75-year-old patients. Similar trends were seen by patient sex. The ADR in women was significantly lower than that in men for every age group, suggesting the importance of reporting the ADR by sex and need for using different benchmarks. Although the ADR in the 45–49-year-old patients in our study meets the current minimum standard quality benchmarks in screening colonoscopy, endoscopists might see a small drop in their ADR once a higher proportion of 45–49-year-old patients start undergoing screening colonoscopy, particularly if their patient population is predominately females.

In addition, an overall ADR of >25% in the 45–49-year-old group also reinforces the need to start screening at age 45 years (3–5). Our reported ADRs in 45–49-year-old patients are similar to those reported by others, many of which included individuals with a family history of CRC (10,11). In another recent study from a large community practice, the overall ADR and ADR by sex in average-risk 45–49-year-old patients undergoing screening colonoscopy were similar to this report (12).

We also found that the overall ADR for persons aged 45–49 years regardless of family history of CRC was similar to findings in those who were average-risk, suggesting that family history, at least as collected by endoscopists in this database, does not affect ADR at younger ages.

Limitations of our study are that the information submitted to the registry is self-reported by individual endoscopists and practices. Although we selected screening examinations where there was no family history of CRC, we do not know if family history information was uniformly collected or entered in the indications. Therefore, it is possible that the ADR in our study is an overestimation of what the ADR in this population might actually be. We also do not know why patients aged 45–49 years underwent screening colonoscopy before 2018. Possible explanation includes that being African Americans, in whom there was guidance to start CRC screening early before 2018, or otherwise concerned individuals or incorrect indication selection. Despite these limitations, this is the largest study evaluating the ADR in patients aged 45–49 years undergoing average-risk screening colonoscopy and provides robust information regarding benchmarks in this age group. Moreover, we have included ADR information for the same endoscopists across all age groups to limit any effect of endoscopists on ADR as well.


Guarantor of the article: Aasma Shaukat, MD, MPH.

Specific author contributions: M.B. and A.S.: concept, design, analysis, writing, and editing article. J.H.: concept, design, analysis, and edits. M.B.P., D.G., and D.K.R.: design, analysis, and editing revisions.

Financial support: Supported by grant from the Steven and Alexandra Cohen Foundation (A.S.).

Potential competing interests: None to report.


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