The efficacy, not the tolerability, of bowel cleansing is the primary concern in patients undergoing colonoscopy, because of the substantial adverse consequences of inadequate bowel preparation, according to a consensus report published simultaneously in Gastroenterology, the American Journal of Gastroenterology, and Gastrointestinal Endoscopy.
As many as 20%-25% of all colonoscopies reportedly have inadequate bowel cleansing, which is associated with lower rates of lesion detection, longer procedure times, and increased electrocautery risks, in addition to the excess costs and risks of repeat procedures. “Efficacy should be a higher priority than tolerability, [so] the choice of a bowel-cleansing regimen should be based on cleansing efficacy first and patient tolerability second,” said Dr. David A. Johnson of Eastern Veterans Administration Medical School, Norfolk (Va.) and his associates on the U.S. Multi-Society Task Force on Colorectal Cancer.
The USMSTF comprised representatives from the American College of Gastroenterology, the American Gastroenterological Association, and the American Society for Gastrointestinal Endoscopy, who compiled recommendations and wrote this report based on a systematic review and meta-analysis of the literature concerning bowel preparation from 1980 to the present.
When selecting a bowel-cleansing regimen for patients, physicians should consider the patient’s medical history, medications, and, if applicable, the adequacy of bowel preparation for previous colonoscopies. High-quality evidence shows that a split-dose regimen of 4 liters of polyethylene glycol–electrolyte lavage solution (PEG-ELS) provides superior bowel cleansing to other doses and solutions. The second dose ideally should begin 4-6 hours and conclude at least 2 hours before the procedure time. However, same-day regimens are acceptable, especially for patients scheduled for an afternoon colonoscopy.
Using a split-dose regimen allows some flexibility with the diet on the day before the procedure. Instead of ingesting only clear liquids, patients can consume either a full liquid or a low-residue diet for part or all of the day preceding colonoscopy, which improves their tolerance of the bowel preparation.
Over-the-counter, nonapproved (by the FDA) bowel-cleansing agents have widely varying efficacy, ranging from adequate to excellent. They generally are safe, but “caution is required when using these agents in certain populations” such as patients with chronic kidney disease. The routine use of adjunctive agents intended to enhance purgation or visualization of the mucosa is not recommended, Dr. Johnson and his associates said (Gastroenterology 2014;147:903-24).
At present, the evidence is insufficient to allow recommendation of specific bowel-preparation regimens for special patient populations such as the elderly, children and adolescents, people with inflammatory bowel disease, patients who have undergone bariatric surgery, and people with spinal cord injury. However, sodium phosphate preparations should be avoided in the elderly, children, and people with IBD. Additional bowel purgatives can be considered for patients at risk for inadequate preparation, such as those with a history of constipation, those using opioids or other constipating medications, those who have undergone previous colon resection, and those with spinal cord injury.
The report also includes recommendations concerning patient education, the risk factors for inadequate bowel preparation, assessing the adequacy of bowel preparation before and during the procedure, and salvage options for cases in which preparation is inadequate. It is available at http://dx.doi.org/10.1053/j.gastro.2014.07.002.