Optimizing Bowel Preparation Quality for Colonoscopy

The US multi-society task force on colorectal cancer (CRC) has updated its 2014 guidance for optimizing the adequacy of bowel preparation for colonoscopy.

The latest consensus recommendations emphasize the importance of verbal and written patient education, refine diet restrictions, update optimal purgative regimens, and advise tracking bowel prep adequacy rates at both the individual endoscopist and unit levels.

“Colorectal cancer remains the second most common cause of cancer death in the United States, and colonoscopy is considered the gold standard for evaluating the colon, including assessing causes of colon-related signs or symptoms and the detection of precancerous lesions. It is well recognized that the adequacy of bowel preparation is essential for optimal colonoscopy performance,” the task force wrote.

Choice of Prep, Dosing and Timing, and Dietary Restrictions 

When choosing bowel preparation regimens, the task force recommends considering the individual’s medical history, medications, and, when available, the adequacy of bowel preparation reported from prior colonoscopies. Other considerations include patient preference, associated additional costs to the patient, and ease in obtaining and consuming any purgatives or adjuncts.

In terms of timing and dose, the task force now “suggests that lower-volume bowel preparation regimens, such as those that rely on only 2 liters of fluid compared to the traditional 4L, are acceptable options for individuals considered unlikely to have an inadequate bowel preparation. This assumes that the purgative is taken in a split-dose fashion (half the evening prior to colonoscopy and half the morning of the colonoscopy),” co-lead author Brian C. Jacobson, MD, MPH, with Massachusetts General Hospital and Harvard Medical School, both in Boston, told Medscape Medical News.

The task force also states that a same-day bowel preparation regimen for afternoon, but not morning, colonoscopy is a “reasonable alternative to the now-common split-dose regimen,” Jacobson said.

The group did not find one bowel preparation purgative to be better than others, although table 7 in the document details characteristics of commonly used prep regimens including their side effects and contraindications.

Recommendations regarding dietary modifications depend upon the patient’s risk for inadequate bowel prep. For patients at low risk for inadequate bowel prep, the task force recommends limiting dietary restrictions to the day before a colonoscopy, relying on either clear liquids or low-fiber/low-residue diets for the early and midday meals. Table 5 in the document provides a list of low-residue foods and sample meals.

The task force also suggests the adjunctive use of oral simethicone (≥ 320 mg) to bowel prep as a way to potentially improve visualization, although they acknowledge that further research is needed.

How might these updated consensus recommendations change current clinical practice? 

Jacobson said, “Some physicians may try to identify individuals who will do just as well with a more patient-friendly, easily tolerated bowel preparation regimen, including less stringent dietary restrictions leading up to colonoscopy.” 

He noted that the task force prefers the term “guidance” to “guidelines.”

New Quality Benchmark 

The task force recommends documenting bowel prep quality in the endoscopy report after all washing and suctioning have been completed using reliably understood descriptors that communicate the adequacy of the preparation.

They recommend the term “adequate bowel preparation” be used to indicate that standard screening or surveillance intervals can be assigned based on the findings of the colonoscopy.

Additionally, the task force recommends that endoscopy units and individual endoscopists track and aim for ≥ 90% adequacy rates in bowel preparation — up from the 85% benchmark contained in the prior recommendations.

Jacobson told Medscape Medical News it’s “currently unknown” how many individual endoscopists and endoscopy units track and meet the 90% benchmark at present.

David Johnson, MD, professor of medicine and chief of gastroenterology at Eastern Virginia Medical School in Norfolk, Virginia, who wasn’t on the task force, said endoscopy units and providers “need to be accountable and should be tracking this quality metric.”

Johnson noted that bowel prep inadequacy has “intrinsic costs,” impacting lesion detection, CRC incidence, and patient outcomes. Inadequate prep leads to “increased risk for morbidity, mortality, longer appointment and wait times for rescheduling, and negative connotations that may deter patients from returning.”

Brian Sullivan, MD, MHS, assistant professor of medicine, Division of Gastroenterology, Duke University School of Medicine, Durham, North Carolina, who wasn’t on the task force, said the recommendation to target a 90% or higher bowel preparation adequacy rate is “appreciated.”

“This benchmark encourages practices to standardize measurement, tracking, and reporting of preparation quality at both the individual and unit levels. Specifically, it should motivate providers to critically evaluate their interpretation of preparation quality and ensure adequate cleansing before making determinations,” Sullivan told Medscape Medical News.

“At the unit level, this metric can identify whether there are opportunities for quality improvement, such as by implementing evidence-based initiatives (provided in the guidance) to enhance outpatient preparation processes,” Sullivan noted.

The task force emphasized that the majority of consensus recommendations focus on individuals at average risk for inadequate bowel prep. Patients at high risk for inadequate bowel prep (eg, diabetes, constipation, opioid use) should receive tailored instructions, including a more extended dietary prep and high-volume purgatives.

‘Timely and Important’ Updates

Sullivan said the updated consensus recommendations on optimizing bowel preparation quality for colonoscopy are both “timely and important.” 

“Clear guidance facilitates dissemination and adoption, promoting flexible yet evidence-based approaches that enhance patient and provider satisfaction while potentially improving CRC prevention outcomes. For instance, surveys reveal that some practices still do not utilize split-dose bowel preparation, which is proven to improve preparation quality, particularly for the right-side of the colon. This gap underscores the need for standardized guidance to ensure high-quality colonoscopy and effective CRC screening,” Sullivan told Medscape Medical News.

He also noted that the inclusion of lower-volume bowel prep regimens and less intensive dietary modifications for selected patients is a “welcome update.”

“These options can improve patient adherence and satisfaction, which are critical not only for the quality of the index exam but also for ensuring patients return for future screenings, thereby supporting long-term CRC prevention efforts,” Sullivan said.

The task force includes representatives from the American Gastroenterological Associationthe American College of Gastroenterology (ACG), and the American Society for Gastrointestinal Endoscopy.

The consensus document was published online in the three societies’ respective scientific journals — Gastroenterology, the American Journal of Gastroenterology, and Gastrointestinal Endsocopy.

This research had no financial support. Jaco bson is a consultant for Curis and Guardant Health. Sullivan had no disclosures. Johnson is an advisor to ISOThrive; a regular contributor to Medscape; and a past president of the ACG.