Brief Article
Copyright ©2012 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Aug 28, 2012; 18(32): 4350-4356
Published online Aug 28, 2012. doi: 10.3748/wjg.v18.i32.4350
Chronic methadone use, poor bowel visualization and failed colonoscopy: A preliminary study
Siddharth Verma, Joshua Fogel, David J Beyda, Brett Bernstein, Vincent Notar-Francesco, Smruti R Mohanty
Siddharth Verma, Vincent Notar-Francesco, Smruti R Mohanty, Department of Internal Medicine, Division of Gastroenterology, New York Methodist Hospital, Weill Cornell Medical College, Brooklyn, NY 11215, United States
Joshua Fogel, Department of Finance and Business Management, Brooklyn College, Brooklyn, NY 11210, United States
David J Beyda, Department of Internal Medicine, Division of Gastroenterology, SUNY Downstate Medical Center University Hospital of Brooklyn, Long Island College Hospital, Brooklyn, NY 11201, United States
Brett Bernstein, Department of Internal Medicine, Division of Gastroenterology, Beth Israel Medical Center, Albert Einstein College of Medicine, New York, NY 10003, United States
Author contributions: Verma S designed the study and wrote the manuscript; Fogel J performed all data analysis and contributed to the authorship and revision of the manuscript; Beyda DJ collected data and contributed to the protocol; Bernstein B assisted in study design; Notar-Francesco V and Mohanty SR edited and revised the manuscript.
Correspondence to: Dr. Siddharth Verma, Department of Internal Medicine, Division of Gastroenterology, New York Methodist Hospital, Weill Cornell Medical College, 3rd floor, Endoscopy Suite, 506 Sixth Street, Brooklyn, NY 11215, United States. vermasi@hotmail.com
Telephone: +1-718-7803851 Fax: +1-718-7803413
Received: May 31, 2012
Revised: July 16, 2012
Accepted: July 28, 2012
Published online: August 28, 2012
Abstract

AIM: To examine effects of chronic methadone usage on bowel visualization, preparation, and repeat colonoscopy.

METHODS: In-patient colonoscopy reports from October, 2004 to May, 2009 for methadone dependent (MD) patients were retrospectively evaluated and compared to matched opioid naive controls (C). Strict criteria were applied to exclude patients with risk factors known to cause constipation or gastric dysmotility. Colonoscopy reports of all eligible patients were analyzed for degree of bowel visualization, assessment of bowel preparation (good, fair, or poor), and whether a repeat colonoscopy was required. Bowel visualization was scored on a 4 point scale based on multiple prior studies: excellent = 1, good = 2, fair = 3, or poor = 4. Analysis of variance (ANOVA) and Pearson χ2 test were used for data analyses. Subgroup analysis included correlation between methadone dose and colonoscopy outcomes. All variables significantly differing between MD and C groups were included in both univariate and multivariate logistic regression analyses. P values were two sided, and < 0.05 were considered statistically significant.

RESULTS: After applying exclusionary criteria, a total of 178 MD patients and 115 C patients underwent a colonoscopy during the designated study period. A total of 67 colonoscopy reports for MD patients and 72 for C were included for data analysis. Age and gender matched controls were randomly selected from this population to serve as controls in a numerically comparable group. The average age for MD patients was 52.2 ± 9.2 years (range: 32-72 years) years compared to 54.6 ± 15.5 years (range: 20-81 years) for C (P = 0.27). Sixty nine percent of patients in MD and 65% in C group were males (P = 0.67). When evaluating colonoscopy reports for bowel visualization, MD patients had significantly greater percentage of solid stool (i.e., poor visualization) compared to C (40.3% vs 6.9%, P < 0.001). Poor bowel preparation (35.8% vs 9.7%, P < 0.001) and need for repeat colonoscopy (32.8% vs 12.5%, P = 0.004) were significantly higher in MD group compared to C, respectively. Under univariate analysis, factors significantly associated with MD group were presence of fecal particulate [odds ratio (OR), 3.89, 95% CI: 1.33-11.36, P = 0.01] and solid stool (OR, 13.5, 95% CI: 4.21-43.31, P < 0.001). Fair (OR, 3.82, 95% CI: 1.63-8.96, P = 0.002) and poor (OR, 8.10, 95% CI: 3.05-21.56, P < 0.001) assessment of bowel preparation were more likely to be associated with MD patients. Requirement for repeat colonoscopy was also significant higher in MD group (OR, 3.42, 95% CI: 1.44-8.13, P = 0.01). In the multivariate analyses, the only variable independently associated with MD group was presence of solid stool (OR, 7.77, 95% CI: 1.66-36.47, P = 0.01). Subgroup analysis demonstrated a general trend towards poorer bowel visualization with higher methadone dosage. ANOVA analysis demonstrated that mean methadone dose associated with presence of solid stool (poor visualization) was significantly higher compared to mean dosage for clean colon (excellent visualization, P = 0.02) or for those with liquid stool only (good visualization, P = 0.01).

CONCLUSION: Methadone dependence is a risk factor for poor bowel visualization and leads to more repeat colonoscopies. More aggressive bowel preparation may be needed in MD patients.

Keywords: Colonoscopy; Methadone; Opioid; Inadequate bowel preparation; Colonoscopy preparation; Methadone dose