Meta-analysis: efficacy of small bowel preparation for small bowel video capsule endoscopy

It is unclear whether small bowel visibility in video capsule endoscopy (VCE) is enhanced by the use of bowel preparation in addition to pre-procedural fasting. The objective of this study was to clarify this issue by means of a systematic review of the literature and meta-analysis.

Randomised controlled trials comparing the use of laxative bowel preparation with fasting alone were identified using a literature search. Categorical measures of treatment efficacy were extracted from qualifying studies and pooled using random-effects meta-analyses. Primary analysis compared any bowel preparation with fasting alone; subsidiary analyses assessed diagnostic yield and results for each regimen.

Eight studies were identified, using either polyethylene glycol (PEG) or sodium phosphate (NaP) based regimens. No qualifying studies were identified using other laxatives. Study quality was sufficiently high to warrant meta-analysis. Use of any form of bowel preparation yielded significantly better visibility than fasting alone (OR = 2.31; 95% CI = 1.46-3.63; p < 0.0001). Similar results were seen for diagnostic yield (OR = 1.88; 95% CI = 1.24-2.84; p = 0.023). When sub-analysed according to the treatment used, PEG-based regimens showed benefit (OR = 3.11; 95% CI = 1.96-4.94; p < 0.0001), while NaP-based regimens yielded no significant difference from fasting alone (OR = 1.32; 95% CI = 0.59-2.96; p < 0.0001).

The study did not consider results from retrospective studies, nor those which did not give a categorical measure of efficacy. The impact of prokinetic and other adjunctive treatments was not considered. The results are only relevant to the most commonly used video capsule, as data for newer alternative devices have not yet been published.

Based on the results of this analysis, the use of bowel preparation alongside fasting is recommended for VCE. PEG-based regimens offer a clear advantage in these patients, while the currently available evidence base does not support the use of NaP. For VCE, lower volume PEG appears to be as efficacious as higher volumes traditionally used for colonoscopy preparation.