Split-Dose Preparations Are Superior to Day-Before Bowel Cleansing Regimens: A Meta-analysis

BACKGROUND & AIMS: There are different regimens of preparing the colon for colonoscopy, including polyethylene glycol (PEG), sodium phosphate, picosulfate, or oral sulfate solutions. We performed a meta-analysis to determine the efficacy of split-dose vs other colon preparation regimens, the optimal products for use, and the most effective preparation volumes. METHODS: We performed systematic searches of MEDLINE, EMBASE, Scopus, CENTRAL, and ISI Web of knowledge databases, from January 1980 to March 2014, for published results from randomized trials that assessed split-dose regimens vs day-before colonoscopy preparation. We excluded studies that included pediatric or hospitalized patients, or patients with inflammatory bowel disease. The primary outcome was efficacy of bowel cleansing. Secondary outcomes included side effects or complications, outcomes of procedures, patients' willingness to repeat the procedure, and the amount of time required for patients to resume daily activities. RESULTS: We identified 47 trials that fulfilled our inclusion criteria (n = 13,487 patients). Split-dose preparations provided significantly better colon cleansing than day-before preparations (odds ratio [OR], 2.51; 95% confidence interval, 1.86-3.39), as well as day-before preparations with PEG (OR, 2.60; 95% confidence interval, 1.46-4.63), sodium phosphate (OR, 9.34; 95% confidence interval, 2.12-41.11), or picosulfate (OR, 3.54; 95% confidence interval, 1.95-6.45). PEG split-dose preparations of 3 L or more yielded greater bowel cleanliness than lower-volume split-dose regimens (OR, 1.89; 95% confidence interval, 1.01-3.46), but only in intention-to-treat analysis. A higher proportion of patients were willing to repeat split-dose vs day-before cleansing (OR, 1.90; 95% confidence interval, 1.05-3.46), and low-volume split-dose preparations vs high-volume split-dose preparation (OR, 4.95; 95% confidence interval, 2.21-11.10). There were no differences between preparations in other secondary outcome measures. However, there was variation among studies in definitions and main and secondary outcomes. CONCLUSIONS: Based on meta-analysis, split-dose regimens increase the quality of colon cleansing and are preferred by patients compared with day-before preparations. Additional research is required to evaluate oral sulfate solution-based and PEG low-volume regimens further.