Polyp detection rate in transverse and sigmoid colon significantly increases with longer withdrawal time during screening colonoscopy

<div><p>Background</p><p>The guidelines for colonoscopy present withdrawal time (WT) and adenoma detection rate (ADR) as the quality indicator. The purpose of this retrospective study is to analyze the predicting factors with polyp detection rate (PDR) as a surrogate for ADR by using comprehensive health checkup data, and assess the correlation between PDR per each colonic segment and WT, and factors influencing WT.</p><p>Methods</p><p>One thousand and thirty six consecutive health checkup cases from April 2015 to March 2016 were enrolled in this study, and 880 subjects who undertook colonoscopy without polyp removal or biopsy were divided into the two groups (polyp not detected group vs polyp detected group). The two groups were compared by subjects and clinical characteristics with univariate analysis followed by multivariate analysis. Colonoscopies with longer WT (≥ 6 min) and those with shorter WT (< 6 min) were compared by PDR per each colonic segment, and also by subjects and clinical characteristics.</p><p>Results</p><p>A total of 1009 subjects included two incomplete colonoscopies (CIR, 99.9%) and overall PDR was 35.8%. A multiple logistic regression model demonstrated that age, gender, and WT were significantly related factors for polyp detection (odds ratio, 1.036; 1.771; 1.217). PDR showed a linear increase as WT increased from 3 min to 9 min (r = 0.989, p = 0.000) and PDR with long WT group was higher than that with short WT group per each colonic segment, significantly in transverse (2.3 times, p = 0.004) and sigmoid colon (2.1 times, p = 0.001). Not only bowel preparation quality but also insertion difficulty evaluated by endoscopist were significant factors relating with WT (odds ratio, 3.811; 1.679).</p><p>Conclusion</p><p>This study suggests that endoscopists should be recommended to take more time up to 9 min of WT to observe transverse and sigmoid colon, especially when they feel no difficulty during scope insertion.</p></div

The impact of visceral adipose tissue as best predictor for difficult colonoscopy and the clinical utility of a long small-caliber scope as rescue

<div><p>Background</p><p>There have been many reports about a variety of factors associated with incomplete colonoscopy or difficult colonoscopy with long cecal intubation time (CIT). The aim of this retrospective study was to analyze the factors related to difficult colonoscopy under conscious sedation and demonstrate the clinical utility of a small-caliber scope as rescue by using the data from a large number of subjects who underwent health check-ups.</p><p>Methods</p><p>Consecutive 1036 cases over a 12-month period (April 2015 to March 2016) were enrolled and 619 subjects were divided into two groups: Easy colonoscopy (CS) Group (CIT ≤ 10 min); Difficult CS Group (CIT > 10 min or incomplete colonoscopy by a standard scope). The two groups were compared by subjects and colonoscopy characteristics with univariate analysis followed by multivariate logistic regression analysis. Reasons for incomplete colonoscopy were also assessed.</p><p>Results</p><p>Cecal intubation rate increased from 97.9% to 99.9% (1007/1008) by the rescue scope. Main reasons for incomplete colonoscopy were tortuosity in the left hemicolon (38%), redundancy in the right hemicolon (29%), pain (19%) and fixation (14%). Moreover, 95% (20/21) of rescue colonoscopies were completed without additional sedation. Higher BMI (21 kg/m² ≤ BMI) and intermediate visceral adipose tissue (VAT) (75 cm² ≤ VAT < 150 cm²) were significantly associated with easy CS (80.7% vs 19.3%, <i>P</i> = 0.004; 56.3% vs 43.7%, <i>P</i> = 0.001) by univariate analysis. Age, gender, and VAT, not BMI, were independently associated with difficult colonoscopy by multivariate analysis (OR (95% CI), <i>P</i>: 0.964 (0.942, 0.985), 0.001; 1.845 (1.101, 3.091), 0.020; 2.347 (1.395, 3.951), 0.001). Subgroup analysis by gender also showed VAT as the best predictor for both genders.</p><p>Conclusion</p><p>Difficult colonoscopy was significantly associated with advancing age, female gender and, lower (< 75 cm²) or higher (150 cm² ≤) VAT. These subjects may benefit from having complete and more comfortable colonoscopy examinations by using the small-caliber scope rather than the standard scope.</p></div

Reasons for incomplete colonoscopy by the standard Q scope (n = 21).

<p>Reasons for incomplete colonoscopy by the standard Q scope (n = 21).</p

Multivariate analysis of the predictors for difficult colonoscopy in females.

<p>Multivariate analysis of the predictors for difficult colonoscopy in females.</p

Univariate analysis of the factors related to difficult colonoscopy.

<p>Univariate analysis of the factors related to difficult colonoscopy.</p

Multivariate analysis of the predictors for difficult colonoscopy in males.

<p>Multivariate analysis of the predictors for difficult colonoscopy in males.</p

Flow chart of the present study.

<p>Flowchart for the selection of study subjects to investigate the factors related to difficult colonoscopy and the clinical usefulness of PQ scope as rescue. CIT: cecal intubation time; CT: computed tomography.</p

Main outcome: Subjects and clinical characteristics.

<p>Main outcome: Subjects and clinical characteristics.</p

Case number with or without polyp detection, and PDR per each value of WT (min).

<p>(A) The left white and right dotted bar graph show case number without polyp detection and with polyp detection, respectively, per each value of WT (minutes). The number of colonoscopy examination per each value of WT, and the percentage of that divided by the total number (n = 878) is indicated above the bar graphs. (B) The polygonal line graph displays PDR per each value of WT. Individual PDR per each value of WT is indicated above the graph. The average PDR for 878 subjects was 28.9%.</p

Predicting factors associated with the presence of colorectal polyp.

<p>Predicting factors associated with the presence of colorectal polyp.</p