Typical Night-Before Colonoscopy Prep May Not
Give Best Results
Scottsdale, AZ—The usual instructions for patients using a polyethylene glycol (PEG) solution for bowel cleansing is to rapidly swallow an 8-ounce glass of solution every 10 minutes until the prescribed amount of liquid has finished or their stool is watery, clear, and free of solid matter.
But is that the best way to prepare the bowel for a colonoscopy?
new study appearing recently in GIE: Gastrointestinal Endoscopy suggests that a split-dose preparation may be better. Researchers from the Mayo Clinic in Arizona found that the alternative method significantly improved both polyp and adenoma detection rates as well as colonoscopy completion rates.
With the split-dose method, patients consume 2 or 3 liters of the preparation the night before and 1 or 2 liters the morning of the procedure.
"In our study, we have demonstrated, for the first time to our knowledge, that system-wide implementation of a split-dose preparation for colonoscopy significantly improves both polyp detection rates and adenoma detection rates as well as improves the quality of the preparation and colonoscopy completion rates,” said
lead study author Suryakanth R. Gurudu, MD, of the Division of Gastroenterology and Hepatology. “These results confirm the benefit of split-dose preparations and the importance of bowel preparation in the detection of colon polyps."
Researchers sought to compare polyp detection rates (PDRs) and adenoma detection rates (ADRs) before and after implementation of split-dose preparations (SDPs) as the preferred bowel preparation in a tertiary GI practice.
Comparison of the quality of the preparation and cecal intubation rates before and after implementation of the SDP were secondary goals. For the meta-analysis, researchers reviewed electronic medical records for all patients undergoing colonoscopy—for screening or as a follow-up—from January 2009 to December 2009 (before SDP) and from October 2010 to March 2011 (after SDP).
The 4-liter PEG electrolyte solution and MoviPrep, marketed by Salix Pharmaceuticals Inc. of Raleigh, NC, were used as the preparations for bowel cleansing. Patients were told to avoid eating a high-fiber diet for 2 days before taking a bowel preparation and to drink only clear liquids for the entire day before the colonoscopy.
Some patients were instructed to drink 3 liters of the 4-liter PEG solutions the night before, starting at 6:00 pm, and 1 liter at least 4 hours before the scheduled procedure time on the day of the procedure. Other patients used MoviPrep prepared according to manufacturer's specifications. They were told to drink half of the volume the night before colonoscopy, starting at 6:00 pm, and the other half at least 4 hours before the scheduled procedure time on the day of the procedure.
Patients who had an early morning procedure or long travel time to the endoscopy unit were given the option of taking the entire preparation the night before, i.e., a nonsplit dose.
The 3,560 patients in the pre-SDP group and the 1,615 patients in the post-SDP group were similar in body mass index and gender as well as age—a median of 62 and 61 years, respectively.
Detection of both PDRs (44.1%-49.5%) and ADRs (26.7%-31.8%) notably improved in the post-SDP group when compared to the pre-SDP group. The cecal intubation rate also increased from 93.6% to 95.5% in the post-SDP group compared to the group not using a split dose.
The percentage of patients with good to excellent preparations increased from 34.9% to 53.9%.
The study's retrospective design and the change in endoscopists over time could affect the applicability of the results, according to the authors.
A related commentary by Lawrence B. Cohen, MD, of the Mount Sinai School of Medicine, noted that “few important advances in the area of bowel preparation have occurred during the past 30 years. Arguably, the most notable advance was the development of an electrolyte-balanced lavage solution. The split-dose bowel regimen warrants recognition because it improves the quality of colonoscopy with little additional effort or expense.”
Cohen noted that some endoscopists have not implemented a split-dose regimen because of concerns about patients’ unwillingness to awaken at night to complete the preparation, long-distance traveling by patients between home and the endoscopy center, or preprocedure fasting guidelines. He pointed out, however, that randomized studies and a meta-analysis confirm that patient tolerance is greater with a split-dose regimen than with a 1-day regimen, especially when patients understand that it improves the quality of examination.