Colonoscopy Preparation — Does a Two-day Bowel Preparation Result in Improved Bowel Cleansing Compared with a One-day Regimen in Patients at Risk for Slow Bowel Transit?

Abstract

Purpose: Inadequate bowel preparation can result in up to one third incomplete colonoscopies. The data are scarce about whether patients with DM, constipation, or those on narcotics are benefited with a more extensive bowel regimen. Our goal was to evaluate the efficacy of two different strategies of polyethylene glycol (PEG) solution administration for bowel prep prior to colonoscopy. Methods: Retrospective review of colonoscopy database between March 1 and June 30, 2009 who had bowel preparation using either a one-day regimen (one day of clear liquid diet+4 L PEG solution+20 mg bisacodyl- 1 day prior to procedure) or a two-day regimen (2 days of clear liquid diet+2 L PEG solution- two days prior and 4 L PEG solution+20 mg bisacodyl- 1 day prior to the procedure). At our institution some physicians routinely order a two-day regimen for those with diabetes, constipation or on prescription narcotics, some exlusively use a one-day regimen, and some occasionally use a two-day regimen. Demographic data including age, BMI, narcotic use, constipation, DM (including oral agents and insulin), and HbA1c levels were obtained. Adequacy of prep quality, cecal and total procedure time, test completeness and procedure indications, and polyps detected were also recorded. Chi square testing and logistic regression were used for categorical variables, and t-tests and linear regression for continuous variables. Results: Records of 300 colonoscopies were reviewed. The mean age was 61.8 and 96.0% were men; 27.0% had DM, 14.1% had constipation, and 21.7% were on narcotics. Primary results are provided in Table 1. In all groups, the adequacy of bowel cleansing was less with two-day regimen, although no differences were statistically significant. Higher BMI was the only variable independently predicting inadequate bowel cleansing (p=0.023). Independent factors negatively impacting exam completeness were again higher BMI (p= 0.032) and two-day prep regimen (p=0.035). Cecal time and total procedure times were statistically not different in one vs. two-day prep groups. The mean number of polyps and adenomas found were not different in one vs. two-day prep groups. Older age and adequate prep quality were independent predictors of finding more polyps (p=0.006 and 0.003, respectively).Table 1: Adequate prep quality in relation to 1 day vs. 2 day prep (all comparisons NS)Conclusion: Patients using a two-day bowel cleansing regimen were more likely to be at risk for slow bowel transit. However, adequate bowel cleansing was not more frequent despite use of the two-day regimen. Inadequate bowel cleansing was related only to increase BMI, and incomplete exams were related only to increased BMI and use of the two-day regimen. Use of a two-day regimen did not result in more adequate bowel cleansing in those at risk for slow bowel transit.