The impact of diet liberalization on bowel preparation for colonoscopy

Unrestricted vs 3-day low-residue diet for colonoscopy preparation. Results of a feasibility randomized trial

AIM

To compare the impact of an unrestricted diet with a 3-day low-residue diet before colonoscopy on bowel preparation quality.

METHODS

A randomized, multicenter, researcher-blinded, parallel-group feasibility trial was conducted to assess the efficacy of an unrestricted diet versus a 3-day low-residue diet for colonoscopy preparation. Participants, aged 50 to 69, were enrolled in a colorectal cancer screening program with no factors linked to poor bowel cleansing. The Boston Bowel Preparation Scale was used to evaluate colon preparation during intubation and withdrawal. Secondary outcomes included bowel exploration time, adenoma and polyp detection rates, and preparation and diet tolerability. The trial is registered under Clinical Trials (NCT04664543).

RESULTS

One hundred and two individuals (mean age 59.3 ± 5.5 years, 40.1% female) were randomly assigned to each diet. All participants in both groups achieved adequate preparation (Boston scores ≥ 2 in each segment). Complete adherence to preparation was observed in the majority of participants in both groups. No significant differences were noted between groups in withdrawal or cecal intubation times, or in adenoma detection rates. The unrestricted diet was better tolerated than the 3-day low-residue diet (82.5% vs. 32.3%). Preparation assessed during intubation was adequate in 82.5% of the unrestricted diet group and in 90.3% of the 3-day low-residue diet group.

CONCLUSIONS

It is feasible to test the impact of an unrestricted diet for adequate bowel preparation. Comparable cleansing results were achieved, but the unrestricted diet showed better tolerability.

Prepackaged formula low-residue diet vs. self-prepared low-residue diet before colonoscopy: A multicenter randomized controlled trial

Background and aims

Compared with self-prepared LRD, a prepackaged low-residue diet (LRD) can improve patient compliance, but whether it can further improve the quality of bowel preparation is uncertain. The study aimed to compare the application of the prepackaged formula LRD with self-prepared LRD in bowel preparation for colonoscopy.

Methods

A multicenter randomized controlled trial was conducted in 15 centers. The eligible subjects were randomly assigned to one of two groups: the formula LRD group and the self-prepared LRD group. On the day before the colonoscopy, subjects in the self-prepared LRD group were instructed to consume a restricted LRD prepared by themselves, while subjects in the formula LRD group were given six bags of prepackaged formula LRD and instructed to consume them according to their individual need. The primary outcome was an adequate bowel preparation rate. Secondary outcomes mainly included Boston Bowel Preparation Scale (BBPS) scores, dietary restriction compliance rate, tolerance, satisfaction, adenoma detection rate (ADR), and adverse reactions. The trial was registered at ClinicalTrials.gov under the identifier NCT03943758.

Results

A total of 550 subjects were recruited. Compared with the self-prepared LRD group, the formula LRD group showed a higher adequate bowel preparation rate (94.5 vs. 80.4%; P < 0.01), BBPS scores (7.87 ± 1.13 vs. 6.75 ± 1.47; P < 0.01), dietary compliance rate (92.4 vs. 78.9%; P < 0.01), tolerance (P < 0.01 in degree of hunger, intensity of physical strength, and negative influence on daily activities), satisfaction (8.56 ± 1.61 vs. 7.20 ± 2.02; P < 0.01), and ADR (25.6 vs. 16.0%; P < 0.01). There was no significant difference in adverse reactions.

Conclusion

Compared with self-prepared LRD, the formula LRD showed similar safety and higher bowel preparation quality, compliance, and tolerance in bowel preparation. More formula LRDs could be designed according to different dietary habits and ethnic populations, and further researches are warranted to confirm their effect.

Clinical trial registration

https://register.clinicaltrials.gov, identifier: NCT03943758.

Efficacy and tolerability of a low-residue diet for bowel preparation: systematic review and meta-analysis

BACKGROUND

Colorectal cancer (CRC) contributes significantly to cancer mortality worldwide. In an effort to reduce the risk of death, detection of polyps through colonoscopy is crucial. The success of the colonoscopy depends on the diet administered the day before the test. Our aim was to evaluate the efficacy, tolerability, and adverse effects of bowel preparation when using a low-residual diet (LRD) compared to a clear-liquid diet (CLD) the day before a scheduled colonoscopy.

METHODS

PubMed/Medline, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL) and Scopus databases were searched. We included studies of patients undergoing a scheduled colonoscopy for CRC screening and surveillance or for diagnostic purposes that compared a LRD with a CLD the day before the colonoscopy. Efficacy, the primary outcome, was evaluated as the rate of adequate bowel preparation. Secondary outcomes were tolerability and adverse effects of bowel preparation.

RESULTS

Thirteen RCTs (N = 2587) were included. Patients receiving a LRD compared to a CLD showed no difference in adequate bowel preparations (RR 1.02; 95% CI 0.99-1.05; I² = 60%). However, the LRD improved patient tolerability (RR 1.17; 95% CI 1.12-1.23; I² = 66%) and had fewer adverse effects (RR 0.89; 95% CI 0.84-0.94; I² = 73%) compared to the CLD. Groups using a LRD with 4L of polyethylene glycol in a single dose or a LRD with < 2000 kcal < 32 g of fibres/day had better tolerability.

CONCLUSION

Based on these findings, our recommendation is strong in favour of a LRD for bowel preparation of patients undergoing a scheduled colonoscopy. This diet could also be useful as a preoperative colonic preparation, but this requires further research.

Polyethylene glycol combined with linaclotide is an effective and well-tolerated bowel preparation regimen for colonoscopy: an endoscopist-blinded, randomized, controlled trial

BACKGROUND AND AIM

Bowel preparation is an important determinant of the quality of colonoscopy. The traditional split-dose regimen of 4 L polyethylene glycol (PEG) solutions for bowel preparation is effective but poorly tolerated. The aim of this was to study the efficacy and tolerability of using linaclotide as an adjunctive agent with low-volume PEG for bowel preparation.

METHODS

This was an endoscopist-blinded, randomized, controlled trial of 432 patients randomly assigned to three groups: 2 L PEG, 4 L PEG and 2 L PEG + 290 µg linaclotide (2 L PEG + L group). The primary outcome measure was efficacy of bowel preparation according to the Boston Bowel Preparation Scale (BBPS), with secondary outcomes of patients' tolerance, defecating frequency, complications, sleeping quality, cecal intubation rate, preparation-to-colonoscopy interval, withdrawal time, cecal intubation time, and adenoma and polyp detection rates.

RESULTS

The percentage of adequate bowel preparation in the 2 L PEG + L group was higher than that of the 2 L PEG group (87.9% vs. 77.0%; P = 0.017), but not the 4 L PEG group (87.9% vs. 91.4%; P = 0.339). In terms of the mean (SD) BBPS score for the total and segmental colons, the bowel cleansing efficacy of 2 L PEG + L was superior to that of 2 L PEG and similar to that of 4 L PEG. Patient's tolerance (including complications, willingness to repeat and sleeping quality) were compatible between the 2 L and 2 L + L group, and the 4 L group was the worst among these three groups.

CONCLUSION

Two liters of PEG combined with 290 µg linaclotide was an effective and well-tolerated bowel preparation regimen.

A Systematic Review and Meta-Analysis of Low-Residue Diet Versus Clear Liquid Diet: Which Is Better for Bowel Preparation Before Colonoscopy?

The goal of this systematic review was to compare the clear liquid diet and the low-residue diet to determine which is better for bowel preparation before colonoscopy. A literature search for randomized controlled trials on the effects of employing the clear liquid diet and low-residue diets before colonoscopy was conducted in major online English databases (PubMed, Web of Science, and Ovid EMBASE). After the systematic review of all 16 studies, the outcomes including quality of bowel preparation, tolerance, willingness to repeat, and adverse effects were analyzed through meta-analysis. The statistical analysis was performed by using RevMan 5.3 software. No statistically significant difference was observed between the low-residue diet and clear liquid diet groups (odds ratio [95% confidence interval] = 1.19 [0.79, 1.81]; p = .41). There was no statistically significant difference between the Boston Bowel Preparation Scale (standard mean difference [95% confidence interval] =-0.04 [-0.21, -0.14]; p = .68) Ottawa Bowel Preparation Scale (standard mean difference [95% confidence interval] =-0.04 [-0.19, 0.11]; p = .59) scores of the two groups. The quality indicators for colonoscopy of the two groups were not statistically significant. However, patient tolerance to the low-residue diet was higher (odds ratio [95% confidence interval] = 1.86 [1.47, 2.36]; p < .01). More patients in the low-residue diet group were willing to repeat the low-residue diet for bowel preparation (odds ratio [95% confidence interval] = 2.34 [1.72, 3.17]; p < .01). More patients in the clear liquid diet group experienced hunger, nausea, and vomiting. People who employed the low-residue diet before colonoscopy had the same quality of bowel preparation as those with clear liquid diet. Meanwhile, the tolerance of people with low-residue diet was better than people with clear liquid diet, and these people were more willing to repeat the colonoscopy with less adverse events.

Comparable quality of bowel preparation with single-day versus three-day low-residue diet: Randomized controlled trial

BACKGROUND AND AIMS

There is controversy about the length of low-residue diet (LRD) for colonoscopy preparation. The aim of the study was to compare one-day vs. three-day LRD associated to standard laxative treatment for achieving an adequate colonoscopy preparation in average risk subjects with positive fecal immunochemical test undergoing screening colonoscopy.

METHODS

A non-inferiority, randomized, controlled, parallel-group clinical trial was performed in the setting of average risk colorectal cancer screening program. Participants were randomized to receive 1-day vs. 3-day LRD in addition to standard polyethilenglicol treatment. Adequacy of preparation was evaluated using the Boston Bowel Preparation Scale (BBPS). Primary outcome was achieving a BBPS ≥ 2 in all colon segments. Analysis was performed for a non-inferiority margin of 5%, a 95% statistical power and one-sided 0.05 significance level.

RESULTS

A total of 855 patients were randomized. Adequate bowel preparation was similar between groups: 97.9% of patients in the 1-day LRD group vs 96.9% in the 3-day LRD group achieved the primary outcome (P-value for non-inferiority < 0.001). The percentage of patients with BBPS scores ≥ 8 was superior in the 1-day LRD group (254 vs 221 in the 3-day LRD group, P = 0.032). The 1-day regimen was better tolerated than the 3-day diet. 47.7% (vs 28.7%, P < 0.05) of patients rated the 1-day LRD as very easy to follow.

CONCLUSION

The 1-day LRD is non-inferior to 3-day LRD for achieving an adequate colon cleansing before average risk screening colonoscopy and it is better tolerated.

Low-residue versus clear liquid diet before colonoscopy: An updated meta-analysis of randomized, controlled trials

Great value in the early identification and treatment of adenomatous polyps or early canceration using colonoscopy has been recognized. A clear colonoscopic vision brought by good intestinal preparation will become crucial. Several studies have completed using the low-residue diet (LRD) versus a clear liquid diet (CLD) the day before colonoscopy that presenting contradictory results. Therefore, a more comprehensive and updated meta-analysis is needed to summarize the findings on the effects of LRD and CLD on intestinal preparation and the quality of coloscopy.The comprehensive search was performed in PubMed/MEDLINE, Scopus, Cochrane databases (February 2020). LRD vs CLD before colonoscopy were included in this study. Mantel-Haenszel or DerSimonian and Laird models with the relative risk (RR) to evaluate differences in intestinal preparation, tolerance, readiness to repeat preparation, detected of a polyp, and overall adverse reactions.Total 16 studies (N = 3413) were eligible. Patients with LRD compared with CLD indicated significantly better of tolerability (RR 0.92;95% CI,0.85-0.99; P < .05) and willingness to repeat intestinal preparation (RR 0.86; 95% CI 0.79-0.93; P < .05), but no differences with adequate intestinal preparations, detected polyp or overall adverse reactions (all P > .05).Patients with LRD the day before colonoscopy show better tolerance and willingness to repeat intestinal preparation, and no difference with adequate intestinal preparations compared with CLD, but the recommended level of evidence is weak. However, in terms of the detection rate of intestinal adenomas, the LRD group is not weaker than the CLD group, for its evidence level is high, and can significantly reduce the hunger experience of patients.

Can a 1-day clear liquid diet with a split -dose polyethylene glycol overcome conventional practice patterns during the preparation for screening colonoscopy?

BACKGROUND/AIMS

A successful screening colonoscopy is closely linked to the quality of a bowel preparation. In this study, we aimed to determine the impact of a 1-day clear liquid diet (CLD) compared to a 3-day combined diet (CMD) accompanied by a split-dose regimen of polyethylene glycol and electrolyte lavage solution (PEG-ELS) for screening colonoscopy.

MATERIALS AND METHODS

This was a prospective, randomized, endoscopist-blinded study. Patients referred for screening colonoscopy were randomized to four groups as a 1-day CLD+PEG-ELS vs. a 1-day CLD+sulfate free (SF)-PEG-ELS and a 3-day CMD+PEG-ELS vs. a 3-day CMD+SF-PEG-ELS. An assessment of the quality of colon cleaning, tolerability to the preparation, and symptoms related to the preparation were recorded.

RESULTS

A total of 506 patients were enrolled in this study. The quality of bowel preparation was significantly inferior in the CMD+PEG-ELS group than CLD+PEG-ELS (p=0.004) and CMD+SF-PEG-ELS groups (p=0.007). There were no statistical differences among the groups in terms of the polyp detection rate. With respect to an easy rating of diet following and the consumption of laxative, there were no significant differences among the four groups. Gastric fullness and nausea/vomiting were pointed out much more, especially in the SF-PEG-ELS users (p=0.008 and p=0.004, respectively).

CONCLUSION

A 1-day CLD was not inferior to a 3-day CMD for colonoscopy preparation in terms of bowel cleaning, the polyp detection rate, and patient tolerance.

Comparison of Polyethylene Glycol versus Lactulose Oral Solution for Bowel Preparation prior to Colonoscopy

Objective

This study was conducted to compare a lactulose oral solution with a polyethylene glycol (PEG) formulation for colonoscopy preparation using the following metrics: quality of cleansing, colonoscopy outcomes, patient/physician satisfaction, and patient tolerability.

Methods

The enrolled patients were randomly divided into two groups and received a single 2 L dose of either PEG (PEG group) or lactulose (Lac group). The Boston Bowel Preparation Scale (BBPS) was used for assessing the cleansing quality of the bowel preparations. Patient tolerability and adverse events were obtained through the completion of questionnaires.

Results

The lactulose oral solution showed superior bowel cleansing compared to PEG, as evidenced by higher BBPS scores in the Lac group for all segments of the colon (P < 0.05). The detection rates of polyps and intestinal lesions in the Lac group (30.68% and 36.36%, respectively) were significantly higher than those in the PEG group (12.50% vs. 13.63%, respectively). For the degree of satisfaction, the Lac group had significantly higher scores compared to the PEG group, as evaluated by both the patients and endoscopist. PEG was associated with an increased incidence of nausea. There were no statistical differences between the groups in terms of vomiting, abdominal pain or fullness, dizziness, unfavorable palatability, dry mouth, palpitation, tinnitus, and tongue numbness.

Conclusion

A single 2 L dose of a lactulose oral solution had higher efficacy, improved tolerability, and acceptable safety for bowel preparation when compared to the same volume of PEG. Thus, a lactulose oral solution may be a potential bowel-cleansing option for colonoscopy preparation.

Randomized Clinical Trial: A Normocaloric Low-Fiber Diet the Day Before Colonoscopy Is the Most Effective Approach to Bowel Preparation in Colorectal Cancer Screening Colonoscopy

BACKGROUND

Clinical guidelines recommend either a clear-liquid diet or a low-fiber diet for colonoscopy preparation. Participants in a screening program are usually motivated healthy individuals in which a good tolerability is important to improve adherence to potential surveillance colonoscopies.

OBJECTIVE

Our aim was to assess whether or not a normocaloric low-fiber diet followed the day before a screening colonoscopy compromises the efficacy of bowel cleansing and may improve the tolerability of bowel preparation.

DESIGN

This is a randomized, endoscopist-blinded, noninferiority clinical trial.

SETTINGS

The study was conducted at a tertiary care center.

PATIENTS

A total of 276 consecutive participants of the Barcelona colorectal cancer screening program were included.

INTERVENTION

Participants were randomly assigned to a clear-liquid diet or a normocaloric low-fiber diet the day before the colonoscopy. Both groups received 4 L of polyethylene glycol in a split-dose regimen.

MAIN OUTCOME MEASURES

Primary outcome was the adequate bowel preparation rate measured with the Boston bowel preparation scale. Secondary outcomes included tolerability, fluid-intake perception, hunger, side effects, and acceptability.

RESULTS

Participants in both groups were similar in baseline characteristics. Adequate bowel preparation was achieved in 89.1% vs 95.7% in clear-liquid diet and low-fiber diet groups, showing not only noninferiority, but also superiority (p = 0.04). Low-fiber diet participants reported less fluid-intake perception (p = 0.04) and less hunger (p = 0.006), with no differences in bloating or nausea.

LIMITATIONS

The single-center design of the study could limit the external validity of the results. The present findings may not be comparable to other clinical settings.

CONCLUSION

A normocaloric low-fiber diet the day before a screening colonoscopy achieved better results than a clear-liquid diet in terms of adequate colon preparation. Moreover, it also improved the perception of hunger and excessive fluid intake. Registered at clinicaltrials.gov: NCT02401802. See Video Abstract at http://links.lww.com/DCR/A829.

Evaluation of the combined effect of factors influencing bowel preparation and adenoma detection rates in patients undergoing colonoscopy

Background

Colonoscopy is a commonly used modality for screening and surveillance of colorectal cancer (CRC). Therefore, it is essential to have adequate bowel preparation (prep) for the procedure which depends on type of bowel regimens, diet before colonoscopy and timing of the procedure.

Aims

The purpose of this study is to analyse the effect of multiple factors on adenoma detection rate (ADR) and prep quality of colonoscopy. This is the also the first study determining outcomes based on various combinations of diet, timing of the procedure and bowel prep regimens.

Methods

This is a retrospective single-centre observational study. Data about diet before procedure, bowel prepprep regimen and timing of the procedure was collected for patients coming for screening colonoscopy.

Results

Patients with split prep had higher good prep rates (73.8% vs 56.2%) and higher ADRs (34.2 % vs 29.9%) as compared with non-split prep. The good prep quality (65.8% vs 62.1%) and ADRs (31.9% vs 31.5%) were comparable in patients who received clear liquid diet as compared with low residue diet. The good results of bowel prep were obtained with split prep with either clear liquids or low residue diet irrespective of the timing of procedure. The poor prep was noticed in patients who underwent procedure in afternoon, with a low restrictive diet and non-split bowel regimen.

Conclusions

The current study adds to our knowledge about the combined effect of multiple variables affecting the bowel prep quality and ADR. It is imperative to opt for the best combination required for colonoscopy, as this will influence the effectiveness of colonoscopies regarding timely cancer detection and prevention.

Impact of diet restriction on bowel preparation for colonoscopy

Diet restriction is one of the difficult parts of bowel preparation for colonoscopy, and many patients do not follow instructions properly. Few studies have evaluated the impact of dietary restriction in real clinical setting. The aim of this study was to study the effect of diet control on bowel preparation with detailed investigation of unacceptable food list in order to reveal what kind of foods are most problematic in clinical practice.Prospective observational study was carried out at a university-affiliated hospital. Around 4 L polyethylene glycol solution was used for bowel preparation on the day of colonoscopy. Patients were allowed to have regular diet until lunch the day before colonoscopy and educated to control diet from 3 days before colonoscopy with information regarding an unacceptable foods list. Factors associated with inadequate bowel preparation were analyzed using univariate statistics and multivariate logistic regression analysis.Of the 245 patients included in the study, 68 patients (27.8%) followed the diet instructions. Fiber-rich vegetables were the most commonly taken unacceptable foods (N = 143, 58.4%). Inadequate bowel preparation (fair and poor by Aronchick scale) was 47.3%. In multivariate analysis, diabetes [odds ratio (OR) 2.878, 95% confidence interval (CI) 1.242-6.671], preparation to colonoscopy interval (OR 1.003, 95% CI 1.000-1.005) and consumption of foods disturbing bowel preparation (OR 2.142, 95% CI 1.108-4.140) were independent predictors of inadequate bowel preparation.We could identify substantially low compliance to diet instructions in real clinical practice. Consumption of any foods disturbing bowel preparation was significant factor predicting inadequate bowel preparation, even though we could not select specific food list compromising preparation significantly. Favorable bowel preparation was achieved in the subgroup compliant to diet restriction, suggesting that regular diet avoiding specific kinds of foods can be possible option for diet restriction before colonoscopy.