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Different Bowel Preparation Schedule Leads to Different Diagnostic Yield of Proximal and Nonpolypoid Colorectal Neoplasm at Screening Colonoscopy in Average-Risk Population

Chiu, Han-Mo M.D., Ph.D.1,4; Lin, Jaw-Town M.D., Ph.D.1,6; Lee, Yi-Chia M.D., Ph.D.1,4; Liang, Jin-Tung M.D., Ph.D.2; Shun, Chia-Tung M.D., Ph.D.3; Wang, Hsiu-Po M.D.1; Wu, Ming-Shiang M.D., Ph.D.1,4,5

Diseases of the Colon & Rectum:
doi: 10.1097/DCR.0b013e318231d667
Original Contribution

BACKGROUND: Accumulating evidence indicates that the timing of bowel preparation is crucial, but its impact on the diagnostic yield of proximal or nonpolypoid colorectal neoplasm remains unclear.

OBJECTIVE: This study aimed to investigate the impact of the timing of bowel preparation on the adenoma detection rate for nonpolypoid colorectal neoplasm at colonoscopy.

DESIGN: This study is a retrospective analysis of a screening colonoscopy cohort database.

SETTING: The investigation was conducted at a screening colonoscopy unit in an university hospital.

PATIENTS: A consecutive series of 3079 subjects who received primary screening colonoscopy with different timing of bowel preparation was analyzed.

INTERVENTION: Different timing of bowel preparation (same day vs prior day) was studied.

MAIN OUTCOME MEASURES: The main outcomes measured were patient demographics, timing of bowel preparation, colon-cleansing levels, diagnostic yields of colonoscopy, including adenoma, advanced adenoma, and nonpolypoid colorectal neoplasm.

RESULTS: There were a total of 1552 subjects in the morning group and 1527 in the evening group. More subjects had proximal adenoma (175, 11.3% vs 138, 9.0%, P = .04), advanced adenoma (68, 4.4% vs 46, 13.0%, P = .044), nonpolypoid colorectal neoplasm (98, 6.3% vs 67, 4.4%, P = .018), proximal nonpolypoid colorectal neoplasm (71, 4.6% vs 40, 2.6%, P = .004), and advanced nonpolypoid colorectal neoplasm (25, 1.6% vs 12, 0.8%, P = .036) detected by same-day preparation. On multivariate regression analysis, the adenoma detection rate was significantly higher in the same-day group regarding overall and proximal adenoma (OR 1.23, 95% CI: 1.00–1.50; OR 1.35, 95% CI: 1.05–1.74), advanced adenoma (OR 1.53, 95% CI: 1.04–2.28), overall, proximal, and advanced nonpolypoid colorectal neoplasm (OR 1.48, 95% CI: 1.06–2.08; OR 1.82, 95% CI: 1.20–2.75; OR 1.96, 95% CI: 1.12–3.37). The adenoma detection rate was also significantly different among endoscopists.

LIMITATION: This was a single-center, nonrandomized trial.

CONCLUSIONS: Improving bowel preparation quality by same-day preparation may lead to enhanced detection of overall, proximal, and advanced nonpolypoid colorectal neoplasm.

Author Information

1 Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan

2 Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan

3 Department of Pathology and Forensic Medicine, National Taiwan University Hospital, Taipei, Taiwan

4 Health Management Center, National Taiwan University Hospital, Taipei, Taiwan

5 Department of Primary Care Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan

6 Department of Internal Medicine, E-DA Hospital and I-Shou University, Kaohsiung County, Taiwan

Funding/Support: This work was supported in part by a research grant from the Department of Health of Taiwan (Center of Excellence for Cancer Research, DOH99-TD-C-111-001).

Financial Disclosure: None reported.

Presented at Digestive Disease Week 2010, New Orleans, LA, May 1 to 5, 2010.

This study was conducted with the approval of the institutional review board of National Taiwan University Hospital: 201004029R.

Correspondence: Ming-Shiang Wu, M.D., Ph.D., Department of Internal Medicine, National Taiwan University Hospital, 7, Chung-Shan South Road, Taipei, Taiwan. E-mail:

© The ASCRS 2011