A meta-analysis has concluded that a 4-Liter split-dose polyethylene glycol prep is best (Clin Gastroenterol Hepatol 2012; 10: 1225-1231).  This is an expected finding and has been discussed previously on this blog (see below).

What is unexpected is the tremendous heterogeneity in studies of bowel preparations. For this study, the investigators identified 1123 potentially relevant references.  Almost all of these were excluded due to criteria which required 1) randomized control trial, 2) English-based language, and 3) specific study design issues.  Thus 9 studies with 2477 patients met inclusion criteria.  Mean age of patients in these studies were 52-59 years.

The pooled odds for excellent or good bowel prep quality for 4-L split-dose PEG was 3.46 compared with other methods.  The comparison regimens included non-split dose PEG, 2-L split-dose PEG, 3-L split dose PEG, Miralax preps (64 oz split dose with or without stimulants).

While the prep results were generally more favorable, there were no differences in other adverse effects, such as cramping, compliance, or overall experience.

Related blog entry:

• split-dose PEG | gutsandgrowth This blog entry discusses a specific prep, describes the Ottawa scale, and provides additional references. In addition, includes a link to Dave Barry’s column on colonoscopy.