Optimal Bowel Cleansing for Colonoscopy in the Elderly Patient (2024)

Abstract

Colonoscopy is an important diagnostic and screening tool for colorectalcancer detection and prevention, and adequate bowel preparation is critical forsuccessful colonoscopy. Complications related to colonoscopy are increased inelderly patients, either directly or indirectly related to the procedure, andthe risks and benefits of colonoscopy procedures need to be carefully consideredin these patients. Recent studies have shown that the 4 liter polyethyleneglycol with a split preparation is safe and effective for elderly patients, andis the preferred preparation for patients with medical comorbidites.Preparations containing sodium phosphate are generally not recommended for theelderly due to increased renal complications. In addition, a low residue dietmay aid in tolerance and willingness to undergo the procedure compared with aclear liquid diet, with comparable bowel preparation adequacy. Risk factors forinadequate bowel preparations include poor adherence to split preparationinstructions or volume of solution ingested, and certain patient relatedmedications and comorbidities, such as diabetes, elevated body mass index, andantidepressant or narcotic use. Methods for achieving safe and adequate bowelpreparations in the elderly include clear instructions, reminder calls, and casemanagement for potential confounding patient related factors.

Keywords: colonoscopy, bowel preparation, colon cancer screening

1. Introduction

Colorectal cancer is the third most common cancer diagnosed in both men andwomen within the United States. In 2016 it is estimated that there will be 95,270new cases of colon cancer and 39,220 new cases of rectal cancer ¹. Colonoscopy is an important diagnostic andscreening tool for colorectal cancer detection and prevention, and adequate bowelpreparation is critical for successful colonoscopy. Previous studies have shown thatinadequate bowel preparation affects as many as 30% of all colonoscopyprocedures in many U.S. facilities ^2–4. Theconsequences of poor bowel preparation include reduced polyp detection rates, highersurgical complication rates, and procedure cancellations ⁵. Poor bowel preparation presents a costly andunnecessary burden upon our health care system.

Elderly patients (>age 65 years) deserve special consideration whenplanning a colonoscopy procedure. Complications related to colonoscopy are increasedin elderly patients, either directly or indirectly related to the procedure.Complications related to bowel preparation regimens may also be increased in theelderly, due to increased incidence of comorbidities such as diabetes, congestiveheart failure, and renal failure. Finally, the benefit of purely screeningcolonoscopy procedures is reduced in elderly patients and careful consideration ofthe risks and benefits is required prior to recommending colonoscopy. In this paperwe will discuss issues specific to the elderly related to colonoscopy procedures,define optimal bowel cleansing, discuss the currently available preparationssuitable for use in the elderly, and methods for improving adherence and outcomes inthis patient group.

We searched the PubMed database between the dates of January 1, 2011 andDecember 1, 2016 for articles related to bowel preparation for colonoscopy with anemphasis on identifying review articles, practice guidelines, and key comparisonstudies. The keywords for the search were: colonoscopy, colon cancer screening,bowel preparation, split-dose, elderly patients, and polyethylene glycol. We alsoexamined the literature referenced that was utilized for review articles. Thepurpose of this survey was to summarize the options available for patients today andthe implications for elderly patients, rather than a systematic review of theprimary literature.

2. Colonoscopy and the elderly patient

While the incidence of colorectal cancer increases with age, the benefits ofscreening are reduced after age 75 by competing morbidities. The current USPreventive Services Task Force (USPSTF) does not recommend routine colon cancerscreening for all patients over the age of 75, but rather that “the decisionto screen for colorectal cancer is an individual one,” and to evaluate theneed for screening based on the patients overall health and risk factors. The USPSTFdid not recommend any routine colorectal cancer screening for patients age 86 andabove ⁶. Elderly patients with aprior history of colorectal neoplasia who are undergoing surveillance colonoscopiesalso have competing comorbidities that need to be taken into consideration whenmaking decisions of whether to repeat these procedures. Tran, et al. performed aretrospective cohort study of 4834 elderly patients (age>75 years; 55.8%male)(median surveillance age, 79 years) and 22,929 individuals in the referencegroup (age 50–74 years; 57.7% male) (median surveillance age, 63years) undergoing surveillance colonoscopy. They found that surveillance in theelderly was associated with a low incidence of CRC (0.24 per 1000 person-years vs3.61 per 1000 person-years in the reference population (P <.001). After adjusting for comorbid illness, the elderly were found to haveincreased post procedure hospitalizations (OR 1.28 [95%CI,1.07–1.53]; P = .006) ⁷. A Charlson score of 2 was also found to beindependently associated with increased risk of post-procedure hospitalization. Theynoted that procedure related complications comprised only 13% ofpost-procedure hospitalizations, and exacerbation of underlying comorbid illness wasa major indication for unplanned admissions (63.1%). These were not directlyrelated to the procedure; however it is possible that exacerbation of underlyingcomorbidities was an indirect consequence of the invasive procedure. These data aresimilar to others who have noted increase risks related to colonoscopy procedures inthe elderly. Kahi, et al. found in a cohort of US veteran patients thatpost-procedure mortality was increased among patients older than 75 years andincreasing Charlson score. Among patients age ≥80 years, the median survivalwas <5 years regardless of Charlson score ⁸. Day, et al. reported a meta-analysis of 20 studies andfound higher rates of cumulative gastrointestinal adverse events in patients≤80 years (incidence rate ratio 1.7; 95% CI, 1.5–1.9)compared with patients less than 80 years ⁹. Warren, et al, reported on a large cohort of elderlyMedicare patients, and found that risks for adverse events after outpatientcolonoscopy were low; however, they increased with age with specific comorbidconditions and depending on whether polypectomy was done ¹⁰. They found that patients with a history ofstroke, chronic obstructive pulmonary disease, atrial fibrillation, or congestiveheart failure had significantly higher risk for serious gastrointestinal eventsfollowing colonoscopy. Finally, a recent large population based prospective study ofMedicare beneficiaries (n=1,355,692) at average risk for colorectal cancerfound that the 8-year risk for colorectal cancer in 70–74 year old subjectswas 2.19% in those who received colonoscopy and 2.62% in those whodid not receive colonoscopy (absolute risk difference, −0.42%[CI, −0.24% to −0.63%]) ¹¹. In subjects aged 75–79years the risk was 2.84% and 2.97%, respectively (risk difference,−0.14% [CI, −0.41 to 0.16]). They also foundthat the excess 30-day risk for any adverse events in the colonoscopy group was 5.6events per 1000 individuals aged 70–74 and 10.3 events per 1000 individualsaged 75–79 years. Taken together, these studies support the recommendationsof the US Preventive Services Task Force to stop colon cancer screening at age 75,and should be used to discuss the risks and benefits of any colonoscopy procedure inelderly patients, especially in those with comorbidities.

3. Definition of optimal bowel cleansing

Several rating systems are used by endoscopists to describe the quality ofthe bowel preparation achieved at the end of the procedure (Table 1). A widely used rating system is the AronchickBowel Preparation Scale because of the simplicity. The rating categories include:Excellent, Good, Fair, Inadequate, and Poor. Inadequate and poor ratings aregenerally equivalent and indicate that the colonoscopy was not successful. Otherwidely used and validated rating systems include the Boston Bowel Preparation Scale(BBPS), which rates the right and the left colon separately, The Ottawa BowelPreparation Quality Scale, Chicago Bowel Preparation Scale, and the HarefieldCleansing Scale (HCS). Details pertaining to the scoring systems used in thesescales are shown in Table 1. Parmar, et al.systematically reviewed the validity and reliability of 5 published and 2preliminary bowel preparation scales and concluded that all the scales demonstrateda range of inter-observer reliability from fair to excellent, however the BBPS wasthe most thoroughly validated scale. In addition, the BBPS is recommended over theAronchick and Ottawa classifications because it does not score for retained fluidand explicitly reflects the quality of the preparation after cleansing andsuctioning efforts. Studies to date have demonstrated that high BBPS measurementshave been associated with greater polyp detection, less repeat colonoscopies, andshorter insertion and withdrawal times ¹².

An adequate bowel preparation is considered to be present if fine mucosaldetail is visible in all portions of the colon such that the endoscopist isconfident that small and flat polyps are detectable, and then recommends thestandard screening or surveillance interval for a follow up procedure. The USMulti-Society Task Force on Colorectal Cancer and American Society ofGastrointestinal Endoscopy has recommended that a preparation is adequate if aftersuctioning and washing the mucosa during the procedure it was deemed adequate forthe detection of lesions greater than 5 mm in size ¹³. Current practice suggests that anyprocedure with a preparation rating of less than excellent or good be accompanied bya recommendation for a shortened follow up interval ¹⁴. There is no data currently available tosuggest that a specific bowel preparation score is considered adequate, however aBBSP score of greater than 5 has been associated with a very low rate (2%)of shortened follow up intervals ¹⁵.

4. Currently available bowel preparations

The currently available bowel preparations are listed in Table 2, along with representative comparison studiesand their outcomes ^16–22. Each preparation has its ownrisks and benefits ¹⁵. The mostcommon preparations include Polyethylene glycol (PEG) electrolyte lavage solution,which come as a 4 liter solution or a 2 liter solution that requires adjuvanttreatments, or sodium phosphate (NaP) type laxatives. Concentrated preparationstypically have a reduced volume allowing for improved compliance and readiness torepeat the procedure ²³. The majordrawback of the larger volume preparations is the volume required and the taste,however these are safer in regards to causing dehydration or electrolyteabnormalities (for a complete summary of the toxicities of all bowel preparationssee Adamcewicz M, et al ²⁴). Ingeneral, studies comparing different bowel preparations did not report differencesin adenoma detection rates, and generally lacked the statistical power to make sucha comparison.

Numerous physiologic changes are common in elderly patients, includingdecrements in renal function, reduced intestinal motility, along with the potentialadverse effects of accumulating cardiovascular, neurologic, and other comorbiditieswith their need for concurrent medications ^{25, 26}. For thesereasons magnesium citrate should also be used with caution in the elderly, and hasbeen associated with age-related increases in serum sodium, potassium, and urea,along with an increased risk for hypermagnesemia, with its resulting cardiac andneurologic complications ^{24, 27}. In addition, elderly patientswith cardiovascular disease may be predisposed to ischemic colitis, which is areported rare complication of bisacodyl use ²⁸. NaP regimens have been associated with renal damage fromtubular toxicity from calcium phosphate. In general the use of NaP or other hyper orhypo-osmotic regimens in elderly patients with reduced renal function should beavoided. Current ASGE guidelines state that “there is insufficient evidenceto recommend specific bowel preparation regimens for elderly persons; however, werecommend that NaP preparations be avoided in this population ¹⁵.”

5. Factors associated with poor bowel preparation

Table 3 summarizes risk factorsassociated with inadequate preparation from various multivariate analyses. Dik, etal. recently described an analysis of 1331 consecutive colonoscopy procedures at 4centers, of which 172 (12.9%) had inadequate bowel preparations ³⁸. The bowel preparation regimens inthis study included split preparations using 4 liter PEG, 2 liter PEG +ascorbic acid, sodium picosulfate + magnesium citrate, or sodium phosphate.In a multivariate analysis the independent factors related to inadequate preparationthe American Society of Anesthesiologists Physical Status Classification Systemscore ≥3, use of tricyclic antidepressants, use of opioids, diabetes,chronic constipation, history of abdominal and/or pelvic surgery, history ofinadequate bowel preparation, and current hospitalization. In this study increasingage, body weight, multiple medications, neurologic disease and cirrhosis were notassociated with bowel preparation adequacy. Other studies have described otherindependent factors associated with inadequate bowel preparations, includingelevated body mass index, older age, diabetes, Parkinson’s disease, use ofnarcotics or antidepressants, hypertension, dementia, among others^{3, 4,39–43} (Table3). Further randomized studies are needed to study interventions that mayimprove upon current bowel preparation regimens in patients with characteristicsindicating they are at high risk for inadequate preparations.

Many of the prior studies of patient-related risk factors for inadequatebowel preparations failed to take into account patient self-report of compliancewith either splitting the preparation or the amount ingested. We recently used aprospective questionnaire given to patients presenting for a colonoscopy procedureto determine factors that correlated with inadequate bowel preparations ⁴⁴. Data from the survey includedpatient compliance with the volume consumed (non-compliance defined as failure tocomplete at least 95% of the PEG solution), patient compliance withinstructions adhere to the timing of the split preparation, self-reported difficultylevel of the preparation, and the highest education level achieved by the patient.These data were supplemented by medical record data regarding gender, age, body massindex, distance from the medical clinic, current medications, mental healthdiagnoses, and other medical diagnoses. Of 500 consecutive patients, 87% (n= 435) had an adequate bowel preparation rating on their colonoscopies while13% (n = 65) had an inadequate bowel preparation rating. Inmultivariate analysis, the most significant factor associated with inadequate bowelpreparation was noncompliance with adherence to splitting the preparation[OR=2.99, 95% CI= (1.35, 6.63),p=0.01]. Ness et al ⁴³, and Chan et al ⁴⁰, also reported that non-adherence with instructions were highlyrelated to inadequate preparations. These data indicate that patient education andinstruction materials are of critical importance.

6. Methods for improving compliance and outcomes

Practice guidelines related to colonoscopy bowel preparations have beenpublished by the US Multi-Society Task Force on Colorectal Cancer ¹⁵. Full compliance to theinstructions of the split-preparation plan has been shown to be a very importantfactor related to adequate bowel preparation. This has been observed in a multitudeof prior bowel preparation studies that directly compared split preps with prepswithout split timing of ingestion. Therefore, methods that emphasize the importanceof compliance with both the timing of ingestion of the preparation in addition tothe entire volume of the preparation are important. This could be achieved byproviding clear instructions and more education to the patients about theirpreparation as well as having health care professionals attentively follow-up on thepatients to verify their understanding of the preparation process by performingpre-procedure calls. The use of patient navigators and enlisting the assistance offamily members can be especially helpful in improving compliance in elderlypatients. In addition, identification of patients who have failed previous bowelpreparations is important in order to identify compliance issues and/or recommend apreparation with increased intensity. Table 4lists specific evidence-based actions that can improve bowel preparation compliance⁴⁵, and we have made aneffort to implement all of these at our institution. MacArther et al. haveemphasized that there is no single intervention that is proven to be the mostimportant for improving compliance, but rather practices should consider a number ofdifferent interventions that combined may be the most effective ⁴⁶.

7. Conclusions

The quality of colonoscopy examinations is a crucial issue for anyendoscopic procedure unit and health care system engaged in colon cancer screeningprograms. It is important to recognize that elderly patients have increased risksfor complications from both colonoscopy bowel preparations and procedures, and therisk-benefit balance for colonoscopy in elderly patients needs to be carefullyconsidered. Overall a split 4 liter PEG split preparation is effective and preferredfor elderly patients with comorbidities. We have provided recommendations forcurrently available bowel preparations and methods to improve the adherence andquality of the preparations. All centers should be engaged in continuous qualityimprovement efforts to improve bowel preparations, reduce the need for repeatedprocedures, and to minimize potential complications.

Acknowledgments

Grant Support: VA San Diego Healthcare System Research Service and NIH UO1 HX001574.

Footnotes

References