The cost of inadequate bowel prep for colonoscopy


Around 14 Million colonoscopies are performed every year in the United States (1). It is the most effective test for the detection and prevention of colorectal cancer, the second leading cause of cancer death in the United States (2). Aside from detection and prevention of colorectal cancer, colonoscopy is also performed for the detection and treatment of lower gastrointestinal tract diseases. All colonoscopies require bowel preparation to clean the colon wall, improve insertion of the colonoscope and allow thorough inspection during withdrawal. Two of the most important quality indicators in colonoscopy, adenoma detection rate and cecal intubation rate are influenced by the quality of the bowel preparation (3, 4, 5, 6). Inadequate bowel preparation is a risk factor for colon gas explosion during therapeutic colonoscopy (7, 8), fecal peritonitis (9), and post-polypectomy bleeding (10).

Inadequate bowel prep also represents a huge cost to the healthcare system. In one study, inadequate bowel preparation increased the direct cost of colonoscopy by 12%-22% depending on the practice setting (11). This cost is attributable to increased duration of the examination and the need for repeated procedures. This study did not include several costs including the indirect costs of inadequate bowel preparation for colonoscopy.

Despite the importance of good bowel preparation, up to 25% of all bowel preparations are considered inadequate (6). The recommended level of adequate bowel preparation is greater than 85% (12).

The Cost to the Individual

Inadequate bowel prep can be costly to the patients. Poor bowel preparation lowers the detection of colon polyps and colorectal cancers thereby increasing the risk of developing colorectal cancer especially if the patient fails to repeat the procedure in a timely fashion. The need for repeated procedures increases the risk of complications and its attendant costs. Often the cost of the purgative is borne by the patient. The cost of transportation is also borne by the patient. Patients are usually required to be accompanied by an adult. The wages of the patient and the accompanying adult is often lost for that day especially for low income hourly-paid workers.

The Cost to the Healthcare System

Inadequate bowel prep increases the time it takes to complete a colonoscopy due to time spent cleaning and suctioning the colon wall (11). This may lead to increased time spent by providers (gastroenterologists, nurses, technicians, anesthesiologists) on a procedure thereby reducing the overall number of colonoscopies performed during the work hours. This may also lead to increased need for medications used in sedation and their attendant costs.

The Cost to the Society

The societal cost of inadequate bowel prep is enormous. Inadequate bowel preparation can lead to increased morbidity and mortality from colorectal cancer as a result of aborted procedures, failure to reschedule, missed lesion and interval cancer. Repeat procedures increase the cost of colonoscopy. There is lost productivity associated with attendance at colonoscopy for the patient and the accompanying adult. Costs associated with inadequate bowel preparation represent opportunity cost for other essential healthcare needs and non-healthcare societal needs.

The Solution

A radical solution is to eliminate the need for bowel preparation for colonoscopy. Indeed, a technology is currently being developed to test this strategy (13). This technology is far from being available and even if developed, cannot provide the therapeutic capabilities of colonoscopy. The most effective solution to the problem of inadequate bowel preparation will likely involve multiple strategies. Since the risk factors for inadequate bowel preparation are known, solutions should be developed to mitigate these risk factors. Poor bowel preparation has been attributed to factors such as chronic constipation, use of constipating medications especially opioids and tricyclic antidepressants, diabetes mellitus, obesity, prior resection of the colon, prior inadequate prep for colonoscopy, Medicaid insurance status, lower educational level, English as a secondary language status, longer wait times, and low health literacy (14, 15, 16, 17, 18, 19, 20, 21,22, 23). Specific therapies can address these risk factors (Table 2).

The Purgative

Solutions to inadequate bowel prep can be approached from three perspectives: the purgative, the patient and the provider (3 P’s, Table 3). Improvements are needed in the agents used for bowel preparation. The purgative has to be effective, affordable and easy to use. The split dosing strategy has become an effective strategy to improve compliance especially when large volume purgatives are used.

The Provider

The provider should be able to identify patients at risk for inadequate bowel prep. Clinical decision tool to identify at risk population and recommend intensive bowel preparation regimen should be developed. The additional therapy may be in form of educational instructions or medication. The clinical decision tool may be embedded in the electronic medical records for easier use.

The Patient

The patient should be able to follow simple instructions regarding bowel preparation. Comprehension of a written colonoscopy preparation leaflet is low especially among patients with low health literacy (22). Bowel preparation instructions should be available in the primary language of the patient. If possible, the instructions should be available in written and video formats. Educational booklet, especially with cartoon visual aid as well as video has been shown to improve the quality of bowel preparation (24, 25, 26). A telephone reminder a day before the procedure has been shown to improve adequacy of bowel preparation (27).   To assure adequate bowel preparation before a patient shows up for colonoscopy, there must be a way for the patient to check their level of preparedness at home. Rectal effluent may predict adequacy of bowel preparation and may be used to guide further bowel preparation (28). Hydrogen breath test can also predict the quality of colonic preparation for colonoscopy though it is currently not being used in clinical practice (29, 30). The information from this bowel preparedness level must be actionable. Patients must be able to use this information to continue or escalate their bowel preparation.

Finally, in the event that inadequate bowel preparation is only identified during colonoscopy, salvage therapies should be available to improve bowel preparation if possible. Water flushes, enemas and additional use of purgative may be used.

Table 1. Cost of Inadequate Bowel Preparation

IndividualHealthcare SystemSociety
Lower detection of polyps

Lower detection of colon cancer

Need to repeat procedure

Increased exposure to risk of complications

Loss to follow-up before re-evaluation

Lost wage

Increased cost (co-pay, purgative, transportation,
Lost productivity (for patient and accompanying adult)
Longer time to achieve cecal intubation

Longer time to complete withdrawal

Increased use of resources (medication, personnel, equipment, materials)
Increased morbidity and mortality from colorectal cancer

Increased healthcare cost

Lost productivity

Opportunity cost

Table 2. Risk Factors for Inadequate Bowel Preparation and Solutions

Type of risk factorsList of risk factorsSolutions

  • Medical

  • Prior inadequate bowel prep

  • Chronic constipation

  • Use of constipating medications like psychotropics, opioid narcotics

  • Diabetes Mellitus

  • Obesity

  • Prior resection of the colon

  • Stroke

  • Dementia

  • Cirrhosis

  • Parkinson disease

  • ≥8 active prescription medications

  • Prior abdominal surgeries like
  • appendectomy, hysterectomy

  • Consider large volume agents alone OR

  • Consider use of large volume agents PLUS adjuncts like bisacodyl or magnesium citrate OR

  • Consider low volume agents PLUS adjuncts like bisacodyl or magnesium citrate

  • Consider intense diet restrictions prior to colonoscopy such as low fiber diet x 72hrs, clear liquid diet x 24hrs.

  • Consider intense educational and patient activation programs

  • Non-medical

  • Age > 60 years

  • Male gender

  • Single or widowed status

  • English as a 2nd language

  • Lower household income

  • Low patient activation

  • Low health literacy

  • Longer wait times

  • Medicaid insurance

  • In-patient status

  • Afternoon colonoscopies

  • Lower educational level, ≤ 12th grade education

  • Provide clear, understandable instructions.

  • Provide instructions in the patient’s language

  • Provide instructions in multiple formats (brochures, video).

  • Open communication channels.

  • Involve a family member or friend

  • Telephone re-education a day before colonoscopy.

  • Instruction reminders (stickers, alarm clocks, phone apps)

Table 3. The 3 P’S of Bowel Preparation

The PurgativeThe PatientThe Provider
(Low volume, acceptable taste)
Able to follow simple prep instructionsIdentify patients at risk for inadequate poor prep.
Effective by itself without an additional agentHave instructions in primary language of the patient. If possible, the instructions should be available in written and video formatsProvide additional therapies (educational or additional prep agents) depending on risk stratification
AffordableReview instructions on bowel prep a day before procedureProvide telephone reminder a day before the procedure
SafeCheck level of preparedness and escalate prep if necessaryHave salvage therapies available if necessary


Don’t be a poor prep


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