A prospective randomized single-blind comparison of three methods of bowel preparation for outpatient flexible sigmoidoscopy

Abstract

Background: Preparation for outpatient flexible sigmoidoscopy using a self-administered phosphate enema is the standard practice in our unit, but it provides acceptable bowel preparation in only 80% of patients. This study compared two methods of bowel preparation with the current standard in an attempt to improve efficacy and acceptability.

Methods: From January to September 2003, patients scheduled for out-patient flexible sigmoidoscopy were prospectively randomized to 3 groups: group 1: one Fleet enema 2 h pre-procedure; group 2: two Fleet enemas, one on the evening prior to sigmoidoscopy and one 2 h pre-procedure; group 3: lactulose 30 ml orally 48 and 24 h prior to sigmoidoscopy, plus a single Fleet enema 2 h pre-procedure. A patient questionnaire was used to assess side effects and tolerance. The endoscopists questionnaire assessed the indication for the procedure, quality of preparation, depth of insertion, and pathological findings identified. Power calculations were based on the 80% acceptable preparation rate obtained using a single enema.

Results: For this study, 305 patients were randomized to the three groups. Patient data were available for 261 patients (group 1 = 105; group 2 = 81; group 3 = 75), and endoscopist data were available for 251 patients (group 1 = 97; group 2 = 79; group 3 = 75). No difference was noted between the groups with regard to age, gender, procedure indication, grade of endoscopist, or patient acceptability variables (ease of use: p = 0.09; assistance required: p = 0.11; cramps experienced: p = 0.84; alternative method: p = 0.25). There was no significant difference between the groups in terms of depth of insertion (p = 0.42-chi-squared test) or abnormalities noted (p = 0.34-chi-squared test). Nor was there any difference in the quality of preparation of patients in group 1 versus group 2 (p = 0.39-Fishers exact test) or group 1 versus group 3 (p = 0.13-Fishers exact). However, lactulose + Fleet resulted in significantly fewer patients with acceptable preparation compared with those who administered two Fleet enemas (p = 0.02- Fishers exact test).

Conclusions: The addition of a Fleet enema or oral lactulose over and above a single Fleet enema gives no significant improvement in the acceptability or efficacy of bowel preparation.