This transcript has been edited for clarity.
Hello. I’m Dr David Johnson, professor of medicine and chief of gastroenterology at Eastern Virginia Medical School and Old Dominion University in Norfolk, Virginia. Welcome back to another GI Common Concerns.
Today, I wanted to highlight important new consensus recommendations from the US Multi-Society Task Force on Colorectal Cancer around colonoscopy preparation. The message behind them is clear: Quality matters. The new threshold for the rate of adequate bowel preparation for both individual endoscopists and endoscopy units is now > 90%.
Having led the US Multi-Society Task Force in 2014, I feel particularly privileged to offer my comments and insights around this group’s latest brilliant work. So, let’s get into what they’ve recommended and provide you with some valuable take-home messages.
Bowel Prep Is Critical
When we talk about quality in colonoscopy, we’re referring to adenoma detection and sessile serrated lesion detection, along with the associated documentation that we perform.
In September 2024, the American College of Gastroenterology (ACG) and American Society for Gastrointestinal Endoscopy (ASGE) put out new recommendations on quality indicators for colonoscopy. In that, they explicitly recommend a performance target of ≥ 90% for adequacy of colon preparations.
Achieving that level of quality is not just about writing a prescription for the prep and instructing your patients to follow through with it. Rather, it means providing guidance around diet modification and medication management and explaining the importance of the prep and how it is integral to colonoscopy performance.
It’s a shared responsibility. You, as well as your staff, need to take the time to discuss it with your patients.
The adequacy of the preparation is central to achieving the best outcome. Our goal is to prevent cancer by detecting and removing polyps and/or finding high-risk lesions for diagnostic study.
Dosing and Diet
The standard of care for colonoscopy prep remains the same as in the prior recommendation: split dosing.
There’s one exception for same-day colonoscopy. If you have an afternoon colonoscopy, split dosing is fine, but a same-day regimen is an acceptable alternative. However, if you have a morning colonoscopy, the experts suggest that we stick to split dosing, as it remains the standard.
Prep volumes are becoming more central to ensuring patient compliance, as they’re more willing to take lower volumes. The task force separated volume into three different categories: high volume (≥ 4 L), low volume (2-4 L), or ultra-low volume (≤ 1 L). They noted that patients prefer the ease of taking a lower-volume prep. However, trial results around ultra-low-volume prep have shown a lot of heterogeneity, which is why it was not recommended by these experts.
Remind patients that “volume” refers to that of the prep itself and doesn’t include any additional liquids they need to consume to compensate. If they tell you they can’t drink that much, they still have to hit the target of the prep volume.
The use of patient navigation tools to help prepare patients for colonoscopy has expanded considerably since we published the last recommendations in 2014. There is now telephonic or automated electronic messaging as well as virtual navigation tools that we can use to improve our patients’ understanding and compliance, including with dietary measures. We should all be aware of these adjunctive tools, which the recommendations strongly suggest that we employ.
The recommendation to include low-residue or low-fiber foods the day of colonoscopy was put forward in 2014. I think it’s been misunderstood for a lot of reasons, one of which is a lack of standardization about what a low-residue diet means. Kudos to the authors of these consensus recommendations, who provided a table of low-residue foods and sample meals, which can easily be incorporated into your own electronic medical records or handouts.
If your patient doesn’t meet the criteria for predictors of inadequate prep, then they should be allowed to at least have some of these foods for breakfast and even for a noon meal. Your patients are perhaps best guided in these efforts by giving them this list of food options.
Additional Predictors of Inadequate Prep
Bowel prep recommendations should also consider discriminants, such as medical history, prior surgeries (especially colon surgery), age, and gender.
Medications are another consideration when you evaluate who might be at risk for an inadequate prep. They include narcotics and anticholinergics, as well as glucagon-like peptide 1 receptor agonists (GLP-1 RAs), which are rising in popularity.
A very interesting article on using artificial intelligence (AI) for improved colonoscopy was recently published, where a team of researchers developed a machine learning predictive model for inadequate bowel preparation.
The everyday use of such technology is still a bit down the road. However, we may soon get to a point where we don’t have to think this all through in our head and incorporate AI to help instead.
Redefining Adequacy
It’s important to understand the new definition of adequacy.
In the prior recommendations, we defined “adequacy” as achieving exclusion of polyps ≥ 6 mm. However, both these new US Multi-Society Task Force recommendations and those of the ACG/ASGE Task Force on Quality in Colonoscopy are starting to redefine adequacy. Adequacy now encompasses the detection of not only adenomas but also sessile serrated lesions, as well as other lesions that may be more complicated.
Adhering to the national standard recommendations requires meeting this new definition of adequacy, which means the exam preparation was sufficient for complying with standard screening and surveillance recommendations based on what you found. That’s really the new axiom.
In fact, compliance with the national standard recommendations is a quality metric in and of itself.
Adjunctive Simethicone
An important addition to these recommendations that I find particularly helpful is around the adjunctive use of simethicone.
Simethicone seems to work best at a dose ≥ 320 mg. It’s available in 80-mg dissolvable sublingual form, so you’d need four to achieve the recommended dose. Tablets come in a variety doses, from 100 mg to 200 mg. There are also liquid drops you can use. You’ll need to figure out the best configuration to meet the recommended dose.
The benefits associated with simethicone are about tolerance, not necessarily improved detection.
Adjunctive simethicone is recommended during the procedure in a very dilute solution. You may remember that simethicone created a lot of consternation when it was reported to be associated with biofilm accumulation of the biopsy channels. Therefore, its delivery during the procedure occurs through a channel that is regularly brushed for disinfection as part of standard cleaning.
Using the most dilute formulation seems to be the best. It gets very sticky at higher concentrations. Therefore, the recommendation is to use 0.5 mL simethicone per 99.5 mL of water.
Modifications After Previous Inadequate Prep
The recommendations surrounding the timing of screening and surveillance intervals following inadequate prep are incredibly important for you to understand.
In 2014, we recommended that patients with an inadequate prep are brought back for a colonoscopy within a year for screening and surveillance. However, we’re finding that that doesn’t happen nearly as often as we think.
In ongoing research we’re performing with Dr Aasma Shaukat, we’re analyzing nearly a million inadequate preparations from a database of approximately 20 million colonoscopies. We’ll provide the data later in the year. I think it will astound you in how starkly it reveals how many patients don’t return within that recommended timeframe. Even in cases where they do come back, it may be only within 5 years, outside of the range we’d consider for screening and surveillance. We may lose these patients forever, which is what we’re finding in a sizable number of cases.
The latest recommendations reiterate the need for patients to return within a year for screening or surveillance colonoscopies when the bowel preparation is deemed inadequate or if a higher-risk finding is detected during the procedure.
Additionally, it is recommended that patients return as soon as possible (generally within 3 months) if they have an abnormal noncolonoscopic colorectal cancer screening — that is, a positive fecal immunochemical test or a positive multitarget stool DNA test.
As the recommendations call for us to ramp up the adenoma detection rate, we need to get these patients to return sooner rather than later. It’s key that patients understand that too.
If a patient has had a previous inadequate bowel prep, the recommendations state that we should make several modifications for standard risk factors.
These modifications, which were given a strong recommendation, include restricting vegetables and legumes for 2-3 days prior to colonoscopy; allowing only clear liquids on the day before colonoscopy; addition of promotility agents, such as linaclotide; treatment of underlying constipation; temporary cessation of anticholinergic medications and GLP-1 RAs; and/or the use of high-volume preps.
High-volume preps should be ≥ 4 L. It is recommended to add 15 mg bisacodyl the afternoon before the colonoscopy.
A low-residue diet should be followed for 2-3 days prior to the procedure, changing to clear liquids the day before.
The same strategy applies to patients who have predictors of inadequate prep. Treat those patients as if they’re going to fail and use the high-volume prep, bisacodyl, and diet modification.
To reiterate, ensuring a quality prep is central to achieving our overall goals in colonoscopy and also in colorectal cancer prevention. Quality is what the patient should expect when a prep is prescribed. Referring physicians and healthcare providers should expect their patients to receive a high-quality colonoscopy prep. It’s our obligation as gastroenterologists to fulfill these expectations.
I’m Dr David Johnson. Thanks for listening.
David A. Johnson, MD, a regular contributor to Medscape, is professor of medicine and chief of gastroenterology at Eastern Virginia Medical School in Norfolk, Virginia, and a past president of the American College of Gastroenterology. His primary focus is the clinical practice of gastroenterology. He has published extensively in the internal medicine/gastroenterology literature, with principal research interests in esophageal and colon disease, and more recently in sleep and microbiome effects on gastrointestinal health and disease.
COMMENTARY
Bowel Prep for Colonoscopy: Quality Matters
DISCLOSURES
| March 27, 2025This transcript has been edited for clarity.
Hello. I’m Dr David Johnson, professor of medicine and chief of gastroenterology at Eastern Virginia Medical School and Old Dominion University in Norfolk, Virginia. Welcome back to another GI Common Concerns.
Today, I wanted to highlight important new consensus recommendations from the US Multi-Society Task Force on Colorectal Cancer around colonoscopy preparation. The message behind them is clear: Quality matters. The new threshold for the rate of adequate bowel preparation for both individual endoscopists and endoscopy units is now > 90%.
Having led the US Multi-Society Task Force in 2014, I feel particularly privileged to offer my comments and insights around this group’s latest brilliant work. So, let’s get into what they’ve recommended and provide you with some valuable take-home messages.
Bowel Prep Is Critical
When we talk about quality in colonoscopy, we’re referring to adenoma detection and sessile serrated lesion detection, along with the associated documentation that we perform.
In September 2024, the American College of Gastroenterology (ACG) and American Society for Gastrointestinal Endoscopy (ASGE) put out new recommendations on quality indicators for colonoscopy. In that, they explicitly recommend a performance target of ≥ 90% for adequacy of colon preparations.
Achieving that level of quality is not just about writing a prescription for the prep and instructing your patients to follow through with it. Rather, it means providing guidance around diet modification and medication management and explaining the importance of the prep and how it is integral to colonoscopy performance.
It’s a shared responsibility. You, as well as your staff, need to take the time to discuss it with your patients.
The adequacy of the preparation is central to achieving the best outcome. Our goal is to prevent cancer by detecting and removing polyps and/or finding high-risk lesions for diagnostic study.
Dosing and Diet
The standard of care for colonoscopy prep remains the same as in the prior recommendation: split dosing.
There’s one exception for same-day colonoscopy. If you have an afternoon colonoscopy, split dosing is fine, but a same-day regimen is an acceptable alternative. However, if you have a morning colonoscopy, the experts suggest that we stick to split dosing, as it remains the standard.
Prep volumes are becoming more central to ensuring patient compliance, as they’re more willing to take lower volumes. The task force separated volume into three different categories: high volume (≥ 4 L), low volume (2-4 L), or ultra-low volume (≤ 1 L). They noted that patients prefer the ease of taking a lower-volume prep. However, trial results around ultra-low-volume prep have shown a lot of heterogeneity, which is why it was not recommended by these experts.
Remind patients that “volume” refers to that of the prep itself and doesn’t include any additional liquids they need to consume to compensate. If they tell you they can’t drink that much, they still have to hit the target of the prep volume.
The use of patient navigation tools to help prepare patients for colonoscopy has expanded considerably since we published the last recommendations in 2014. There is now telephonic or automated electronic messaging as well as virtual navigation tools that we can use to improve our patients’ understanding and compliance, including with dietary measures. We should all be aware of these adjunctive tools, which the recommendations strongly suggest that we employ.
The recommendation to include low-residue or low-fiber foods the day of colonoscopy was put forward in 2014. I think it’s been misunderstood for a lot of reasons, one of which is a lack of standardization about what a low-residue diet means. Kudos to the authors of these consensus recommendations, who provided a table of low-residue foods and sample meals, which can easily be incorporated into your own electronic medical records or handouts.
If your patient doesn’t meet the criteria for predictors of inadequate prep, then they should be allowed to at least have some of these foods for breakfast and even for a noon meal. Your patients are perhaps best guided in these efforts by giving them this list of food options.
Additional Predictors of Inadequate Prep
Bowel prep recommendations should also consider discriminants, such as medical history, prior surgeries (especially colon surgery), age, and gender.
Medications are another consideration when you evaluate who might be at risk for an inadequate prep. They include narcotics and anticholinergics, as well as glucagon-like peptide 1 receptor agonists (GLP-1 RAs), which are rising in popularity.
A very interesting article on using artificial intelligence (AI) for improved colonoscopy was recently published, where a team of researchers developed a machine learning predictive model for inadequate bowel preparation.
The everyday use of such technology is still a bit down the road. However, we may soon get to a point where we don’t have to think this all through in our head and incorporate AI to help instead.
Redefining Adequacy
It’s important to understand the new definition of adequacy.
In the prior recommendations, we defined “adequacy” as achieving exclusion of polyps ≥ 6 mm. However, both these new US Multi-Society Task Force recommendations and those of the ACG/ASGE Task Force on Quality in Colonoscopy are starting to redefine adequacy. Adequacy now encompasses the detection of not only adenomas but also sessile serrated lesions, as well as other lesions that may be more complicated.
Adhering to the national standard recommendations requires meeting this new definition of adequacy, which means the exam preparation was sufficient for complying with standard screening and surveillance recommendations based on what you found. That’s really the new axiom.
In fact, compliance with the national standard recommendations is a quality metric in and of itself.
Adjunctive Simethicone
An important addition to these recommendations that I find particularly helpful is around the adjunctive use of simethicone.
Simethicone seems to work best at a dose ≥ 320 mg. It’s available in 80-mg dissolvable sublingual form, so you’d need four to achieve the recommended dose. Tablets come in a variety doses, from 100 mg to 200 mg. There are also liquid drops you can use. You’ll need to figure out the best configuration to meet the recommended dose.
The benefits associated with simethicone are about tolerance, not necessarily improved detection.
Adjunctive simethicone is recommended during the procedure in a very dilute solution. You may remember that simethicone created a lot of consternation when it was reported to be associated with biofilm accumulation of the biopsy channels. Therefore, its delivery during the procedure occurs through a channel that is regularly brushed for disinfection as part of standard cleaning.
Using the most dilute formulation seems to be the best. It gets very sticky at higher concentrations. Therefore, the recommendation is to use 0.5 mL simethicone per 99.5 mL of water.
Modifications After Previous Inadequate Prep
The recommendations surrounding the timing of screening and surveillance intervals following inadequate prep are incredibly important for you to understand.
In 2014, we recommended that patients with an inadequate prep are brought back for a colonoscopy within a year for screening and surveillance. However, we’re finding that that doesn’t happen nearly as often as we think.
In ongoing research we’re performing with Dr Aasma Shaukat, we’re analyzing nearly a million inadequate preparations from a database of approximately 20 million colonoscopies. We’ll provide the data later in the year. I think it will astound you in how starkly it reveals how many patients don’t return within that recommended timeframe. Even in cases where they do come back, it may be only within 5 years, outside of the range we’d consider for screening and surveillance. We may lose these patients forever, which is what we’re finding in a sizable number of cases.
The latest recommendations reiterate the need for patients to return within a year for screening or surveillance colonoscopies when the bowel preparation is deemed inadequate or if a higher-risk finding is detected during the procedure.
Additionally, it is recommended that patients return as soon as possible (generally within 3 months) if they have an abnormal noncolonoscopic colorectal cancer screening — that is, a positive fecal immunochemical test or a positive multitarget stool DNA test.
As the recommendations call for us to ramp up the adenoma detection rate, we need to get these patients to return sooner rather than later. It’s key that patients understand that too.
If a patient has had a previous inadequate bowel prep, the recommendations state that we should make several modifications for standard risk factors.
These modifications, which were given a strong recommendation, include restricting vegetables and legumes for 2-3 days prior to colonoscopy; allowing only clear liquids on the day before colonoscopy; addition of promotility agents, such as linaclotide; treatment of underlying constipation; temporary cessation of anticholinergic medications and GLP-1 RAs; and/or the use of high-volume preps.
High-volume preps should be ≥ 4 L. It is recommended to add 15 mg bisacodyl the afternoon before the colonoscopy.
A low-residue diet should be followed for 2-3 days prior to the procedure, changing to clear liquids the day before.
The same strategy applies to patients who have predictors of inadequate prep. Treat those patients as if they’re going to fail and use the high-volume prep, bisacodyl, and diet modification.
To reiterate, ensuring a quality prep is central to achieving our overall goals in colonoscopy and also in colorectal cancer prevention. Quality is what the patient should expect when a prep is prescribed. Referring physicians and healthcare providers should expect their patients to receive a high-quality colonoscopy prep. It’s our obligation as gastroenterologists to fulfill these expectations.
I’m Dr David Johnson. Thanks for listening.
David A. Johnson, MD, a regular contributor to Medscape, is professor of medicine and chief of gastroenterology at Eastern Virginia Medical School in Norfolk, Virginia, and a past president of the American College of Gastroenterology. His primary focus is the clinical practice of gastroenterology. He has published extensively in the internal medicine/gastroenterology literature, with principal research interests in esophageal and colon disease, and more recently in sleep and microbiome effects on gastrointestinal health and disease.
Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.
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