Judgement of the quality of bowel preparation at screening flexible sigmoidoscopy is associated with variability in adenoma detection rates

The Boston bowel preparation scale: a valid and reliable instrument for colonoscopy-oriented research

BACKGROUND

Few bowel-preparation rating scales have been validated. Most scales were intended for comparing oral purgatives and fail to account for washing and/or suctioning by the endoscopist. This limits their utility in studies of colonoscopy outcomes, such as polyp-detection rates.

OBJECTIVE

To develop a valid and reliable scale for use in colonoscopy outcomes research.

SETTING

Academic medical center.

METHODS

We developed the Boston bowel preparation scale (BBPS), a 10-point scale that assesses bowel preparation after all cleansing maneuvers are completed by the endoscopist. We assessed interobserver and intraobserver reliability by using video footage of colonoscopies viewed on 2 separate occasions by 22 clinicians. We then applied the BBPS prospectively during screening colonoscopies and compared BBPS scores with clinically meaningful outcomes, including polyp-detection rates and procedure times.

RESULTS

The intraclass correlation coefficient (a measure of interobserver reliability) for BBPS scores was 0.74. The weighted kappa (a measure of intraobserver reliability) for scores was 0.77 (95% CI, 0.66-0.87). During 633 screening colonoscopies, the mean (SD) BBPS score was 6.0 +/- 1.6. Higher BBPS scores (> or =5 vs <5) were associated with a higher polyp-detection rate (40% vs 24%, P < .02). BBPS scores were inversely correlated with colonoscope insertion (r = -0.16, P < .003) and withdrawal (r = -0.23, P < .001) times.

LIMITATIONS

Single-center study.

CONCLUSIONS

The BBPS is a valid and reliable measure of bowel preparation. It may be well suited to colonoscopy outcomes research because it reflects the colon's cleanliness during the inspection phase of the procedure.

Bowel preparation before colonoscopy in the era of mass screening for colo-rectal cancer: a practical approach

Colonoscopy constitutes the principal investigation for colo-rectal neoplasms due to its ability to detect and remove most of precancerous lesions; due to the ongoing or planned colon cancer screening programs in many European countries we should expect an enormous increase in colonoscopic demand over the next few years. Diagnostic accuracy and therapeutic safety of colonoscopy strictly depends upon the quality of bowel cleansing which is often perceived as the most unpleasant part of the procedure in individuals undergoing this examination. The ideal preparation for colonoscopy should reliably empty the colon from all faecal material allowing the optimal visualization of the entire colonic mucosa without causing great patient's discomfort nor significant shifts in fluids or electrolytes. Standard PEG solutions and sodium phosphate (NaP) compounds are the most frequently used preparations; both are accepted and relatively well tolerated by the majority of patients undergoing colonoscopy; however, NaP compounds should be avoided in elderly subjects as well as in those with congestive heart failure, renal and hepatic insufficiency or taking diuretics, ACE inhibitors or angiotensin receptor blockers, since they can induce severe electrolyte and/or fluid disturbances. Standard PEG solutions are often taken incompletely due to the low palatability and the high volume of liquids required which induce nausea and vomiting with negative consequences in terms of colon cleansing. Reduced volume and better palatability of PEG solutions, such as those obtained with the newest PEG formulations, as well as improved patient education concerning the importance of bowel cleansing could undoubtedly increase compliance with oral bowel preparations and promote adherence to colo-rectal cancer screening programs.

Colonic lavage with two polyethylene glycol solutions prior to colonoscopy makes no difference: a prospective randomized controlled trial

OBJECTIVE

It is suggested that bowel preparations for colonoscopy are easier to tolerate when a smaller volume of solution with a more pleasant taste is used. The aim of this study was to establish equivalence between a 3-l sulphate-free polyethylene glycol solution (SF-PEG) and a 4-l PEG solution in effectiveness, patients' acceptability and tolerability.

MATERIAL AND METHODS

The study comprised 110 patients scheduled for elective colonoscopy and randomized to receive either SF-PEG or PEG. Before colonoscopy, the patients completed a questionnaire on stool frequency, medication, concomitant diseases, the amount of solution ingested, willingness to re-take it, volume of other fluid taken and tolerance of bowel preparation, taste of the laxative and occurrence of abdominal cramps. Three experienced endoscopists, blinded to the type of preparation, assigned bowel-cleansing scores using a validated 5-point scale to assess cleansing effect.

RESULTS

Data were available for 102 patients (44 M (40%), mean age 53 years, range 23-83 years). No significant differences were found in cleansing the rectosigmoid (p = 0.71) or complete colon (p = 0.79). Diverticulosis, constipation, gender and body mass index (BMI) did not influence cleansing. There was no significant difference in compliance between the two groups (p = 0.61). No differences were found for tolerance, taste and abdominal cramps. Patients who received SF-PEG had a preference for the same preparation next time in comparison with patients who had PEG cleansing (17 (33%) versus 4 (8%), respectively) (p = 0.03).

CONCLUSIONS

Both preparations are comparable in their cleansing effect and toleration. However, patients prefer cleansing with a smaller volume of solution. Improving the acceptability of colonic preparation could improve willingness to undergo colonoscopies in the future.

A motor-driven single-use colonoscope controlled with a hand-held device: a feasibility study in volunteers

BACKGROUND

Several new instruments have been developed in the effort to improve the acceptance of colonoscopy for colorectal cancer screening. A new colonoscope, the Invendoscope, is presented here. It consists of an endoscopic sheath with an inverted sleeve, instrument channel, and an electrohydraulic deflecting tip. The instrument is steered by a hand-held device and propelled by a motorized drive unit.

OBJECTIVE

Our purpose was to evaluate the feasibility of the new Invendoscope SC40.

DESIGN

Prospective single-arm pilot study over 2 time periods using 2 different instrument prototypes (170 and 180/200 cm).

PATIENTS

Thirty-four healthy volunteers (19 men, mean age 49.7 years). Technical instrument defects led to premature termination in 5 additional volunteers during the 2 study periods (4 in phase 1, 1 in phase 2), who were excluded from further analysis.

INTERVENTIONS

Total colonoscopy was attempted, with all procedures being performed without sedation.

MAIN OUTCOME MEASUREMENTS

Cecal intubation rate.

RESULTS

The cecum was reached in 82% of the 34 cases (95% CI, 66%-92%), with better results in period 2 than in period 1 (90% vs 79%); of the 6 incomplete examinations, 4 reached the mid transverse colon or beyond and 2 were stopped in the sigmoid colon because of pain. The volunteer rating showed a mean score of 1.96 (range 1-6; 1 = no discomfort). No complications were encountered.

LIMITATIONS

No data regarding diagnostic accuracy and no data comparing the instrument with conventional colonoscopy are available as yet.

CONCLUSIONS

This pilot proof-of-principle study of a new motor-driven colonoscope showed promising cecal intubation rates and an absence of pain in 92% of cases. Further clinical and comparative studies are warranted.

Adenoma detection rate and the quality of colonoscopy: the sword has two edges

With the increasing demand for colonoscopy for colorectal cancer screening and surveillance of colorectal adenomas and carcinomas, there has been an increasing emphasis on the quality of colonoscopy. Few publications have considered the full implications of pushing the adenoma detection rate as a prime quality indicator. In this article, some of the potential problems with this course are discussed and an alternative approach is suggested. Although defining and measuring quality in colonoscopy is important, further work needs to be done to arrive at a practical, clinically meaningful way of quality assessment.

The impact of colon cleanliness assessment on endoscopists' recommendations for follow-up colonoscopy

OBJECTIVE

Repeat colonoscopy is advocated for low-quality preparations. However, there are few data on how endoscopists assess the quality of bowel preparation. We aimed to investigate, in a visually reproducible manner, endoscopists' assessment of colon cleanliness, as reflected by their subsequent recommendations for follow-up.

METHODS

Gastroenterologists attending the Israeli Gastroenterology Association meeting were presented with photographs depicting varying degrees of colon cleanliness at a hypothetical screening colonoscopy. Endoscopists were requested to denote their recommendation for the timing of a follow-up procedure for each of the different preparations, both when no polyps were detected and when two small adenomas were found.

RESULTS

Seventy-eight gastroenterologists were included. There was considerable interobserver variability in endoscopists' assessment of preparation adequacy, and recommended follow-up timing ranged from more than 5 yr to immediate repeat colonoscopy for identical preparations. Interestingly, even when repeat colonoscopy was not considered necessary, most endoscopists recommended progressively shorter follow-up intervals in line with reduced preparation quality (mean interval dropping from 9.2+/-1.7 to 6.3+/-2.8 to 2.5+/-2 yr, P<0.001 for trend). Similar findings were observed when two adenomas were hypothetically found on the index procedure, although follow-up intervals were shorter. No correlation was found between endoscopists' clinical experience or acquaintance with clinical guidelines and their actual recommendation.

CONCLUSIONS

Clinical decisions derived from colon cleanliness assessment vary considerably among endoscopists, and there is little agreement on what constitutes a disqualifying preparation. Moreover, when confronted with an intermediate-quality preparation, most gastroenterologists recommend a shorter follow-up interval, rather than repeating the procedure. Further studies are required to validate this management approach and to standardize the assessment of preparation quality.

Systematic review: oral bowel preparation for colonoscopy

BACKGROUND

There are many published trials of colon cleansing regimens for colonoscopy but no clear consensus regarding relative performance.

AIM

To identify high quality controlled trials comparing two or more bowel preparation regimens and to compare efficacy and tolerability.

METHODS

A comprehensive systematic review was carried out to identify candidate studies. Quality appraisal was carried out on all identified studies. Results were meta-analysed where possible and qualitatively compared if not.

RESULTS

Eighty-two studies qualified for analysis. Polyethylene glycol and sodium phosphate were the most frequently investigated preparations. There was no significant efficacy difference between the two, but sodium phosphate was better tolerated. Sodium picosulphate/magnesium citrate, a commonly prescribed preparation, was investigated in four studies, with no clear benefit over other regimens demonstrated. Safety was not recognized as a problem in the randomized controlled trials. Published case series demonstrate that sodium phosphate is associated with the highest risk of clinically significant electrolyte disturbances.

CONCLUSION

Shortcomings in study design limit the value of many of the studies. Based on these results, no single bowel preparation emerges as consistently superior. New preparations are required that combine better efficacy and tolerability, in addition to rigorous new validated study designs, allowing unequivocal comparisons to be made.

Results of a prospective randomised multicentre controlled trial comparing a new 2-L ascorbic acid plus polyethylene glycol and electrolyte solution vs. sodium phosphate solution in patients undergoing elective colonoscopy

BACKGROUND

Elective colonoscopy is used increasingly to screen at risk patients for colonic malignancy. Bowel preparation quality is a critical factor for successful screening. Preparations used include high doses of potent laxatives, e.g. sodium phosphate solution or high volume polyethylene glycol. Because of constraints and limited patient acceptability, there remains a need for a more acceptable bowel preparation with at least equivalent cleansing to existing preparations.

AIM

To determine if a 2-L polyethylene glycol solution with electrolytes and ascorbic acid (polyethylene glycol + ascorbic acid) produces equivalent bowel cleansing to sodium phosphate solution, and is acceptable to patients and well tolerated.

METHODS

This was a single blind, parallel group, equivalence study comparing polyethylene glycol + ascorbic acid with sodium phosphate solution in 352 patients undergoing elective colonoscopy. A blinded, independent expert scored a video recording of each colonoscopy. Patients completed a questionnaire reporting acceptability of the bowel preparation process.

RESULTS

Clinically successful bowel preparation was reported in 72.5% of cases prepared using polyethylene glycol + ascorbic acid and in 63.9% of cases prepared using sodium phosphate solution (treatment difference +8.6%, 95% confidence interval -2.3%, +19.4%). The new solution was well accepted and better tolerated than sodium phosphate solution.

CONCLUSIONS

The new 2-L solution of polyethylene glycol + ascorbic acid was at least as efficacious as sodium phosphate solution with comparable efficacy and a better tolerability profile.