Original article
Clinical endoscopy
Effective bowel cleansing before colonoscopy: a randomized study of split-dosage versus non-split dosage regimens of high-volume versus low-volume polyethylene glycol solutions

https://doi.org/10.1016/j.gie.2010.02.048Get rights and content

Background

Adequate bowel cleansing is essential for a high-quality, effective, and safe colonoscopy.

Objectives

To evaluate the degree of colon cleansing comparing split-dosage versus non-split-dosage intake of two different polyethylene glycol (PEG) volumes (low-volume PEG + ascorbic acid vs standard-volume PEG-electrolyte solution) and to identify predictors of poor bowel cleansing.

Design

Single-blind, active control, randomized study.

Setting

Tertiary-care institutions in Italy.

Patients

This study involved adult patients undergoing elective colonoscopy.

Intervention

Colonoscopy with different bowel preparation methods.

Main Outcome Measurements

Degree of bowel cleansing.

Results

We randomized 895 patients, and 868 patients were finally included in intention-to-treat (ITT) analysis. Overall compliance was excellent (97%) for both preparation methods. No difference in tolerability was recorded. Palatability was superior with low volume compared with high volume (acceptable or good 58% vs 51%, respectively, P < .005), independently of intake schedule. PEG plus ascorbic acid produced the same degree of cleansing as standard-volume PEG-electrolyte solution (77% vs 73.4%, respectively, within the split-dosage group and 41.7% vs 44.3%, respectively, within the non-split-dosage group). Independently of PEG volumes, the split-dosage regimen produced markedly superior cleansing results over the same-day method (good/excellent 327/435, 75.2% vs 186/433, 43.0%, P = .00001). Maximum cleansing was observed in colonoscopies performed within 8 hours from the last fluid intake versus over 8 hours from the last fluid intake (P < .001). The degree of bowel cleansing affected both cecal intubation (failed intubation 11.7% with fair/poor preparation vs 1.2% with good/excellent preparation, P = .00001) and polyp detection rates (12.2% with fair/poor vs 24.6% with good/excellent preparation, P = .001). Aborted procedures were significantly more frequent in the non-split-dosage arm (21.2% vs 6.9%, odds ratio [OR] 3.60 [2.29-5.77], P < .0001). Independent predictors of poor bowel cleansing were male sex (OR 1.45 [1.08-1.96], P = .014) and a non-split-dosage bowel preparation schedule (OR 2.08 [1.89-2.37], P = .0001).

Conclusion

Low-volume PEG plus ascorbic acid is as effective as high-volume PEG-electrolyte solution but has superior palatability. A split-dosage schedule is the most effective bowel cleansing method. Colonoscopy should be performed within 8 hours of the last fluid intake.

Section snippets

Design of the study

This was a single-blind, active control, prospective, randomized study of adult patients undergoing routine elective colonoscopy. All patients with an appropriate indication to colonoscopy were considered eligible. Exclusion criteria were pregnant or lactating women, age less than 18 years, significant gastroparesis or gastric outlet obstruction or ileus, known or suspected bowel obstruction or perforation, phenylketonuria or glucose-6-phosphate dehydrogenase deficiency, severe chronic renal

Results

Study participant allocation is recorded in Figure 1. Of the 926 patients assessed for eligibility, 31 were excluded for contraindications (9 for severe chronic renal failure, 6 for age <18 years, 2 for dementia, 6 for cerebrovascular disease, and 8 for severe hypertension). A total of 895 patients were included and randomized to the split-dosage schedule (N = 448) or to the non-split-dosage schedule (N = 447). Nine patients had a major protocol deviation (2 patients had a double dose of PEG

Discussion

The results of our study add to the generalizability of the finding that the low-volume PEG plus ascorbic acid solution is as effective as the standard 4 L PEG solution, with equivalent degrees of colon cleansing.18, 20 Efficacy was coupled with an excellent safety profile. Adverse events were infrequent and of minor clinical relevance. Compliance to complete preparation was surprisingly high in our study, with no difference among volumes or intake schedules. Possible explanation resides in the

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  • Cited by (150)

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    DISCLOSURE: All authors disclosed no financial relationships relevant to this publication.

    See CME section; p. 392

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