Low-residual diet versus clear-liquid diet for bowel preparation before colonoscopy: meta-analysis and trial sequential analysis of randomized controlled trials

Optimal bowel preparation for colonoscopy

There is robust evidence to indicate a strong correlation between the bowel preparation status and adenoma detection rate (ADR), which directly impacts the incidence and mortality rate of postcolonoscopy colorectal cancer. Therefore, improving bowel preparation has been of increasing interest. In Japan, commercially available bowel preparation agents include polyethylene glycol, oral sodium sulfate, sodium picosulfate-magnesium citrate, magnesium citrate, and oral sodium phosphate; each has its own strengths and limitations. The timing of administration can also influence the efficacy of bowel preparation and patient tolerability. Furthermore, meta-analyses have suggested predictive factors for inadequate bowel preparation. A detailed understanding of these factors could contribute to reducing the need for repeat colonoscopy within 1 year, as recommended for patients with inadequate bowel preparation. Recent advancements, such as oral sulfate tablets, present promising alternatives with higher patient satisfaction and ADRs than traditional methods. Achieving optimal bowel preparation requires enhanced instructions, individualized regimens, and a comprehensive understanding of patient backgrounds and the characteristics of various bowel preparation agents. This article provides a concise overview of the current status and advancements in bowel preparation for enhancing the quality and safety of colonoscopy.

One-day versus three-day low-residue diet bowel preparation regimens before colonoscopy: a meta-analysis of randomized controlled trials

BACKGROUND AND AIM

Although studies have shown that the quality of bowel preparation with low-residue diet (LRD) is as effective as that of clear fluid diet (CLD), there is currently no consensus on how long an LRD should last. The aim of this study was to compare a 1-day versus 3-day LRD on bowel preparation before colonoscopy.

METHODS

A systematic review search was conducted in MEDLINE/PubMed, EMBASE, Web of Science, and Cochrane database from inception to April 2023. We identified randomized controlled trials (RCTs) that compared 1-day with 3-day LRD bowel cleansing regiments for patients undergoing colonoscopy. The rate of adequate bowel preparation, polyp detection rate, adenoma detection rate, tolerability, willingness to repeat preparation, and adverse events were estimated using odds ratios (OR) and 95% confidence interval (CI). We also performed meta-analysis to identify risk factors and predictors of inadequate preparation.

RESULTS

Four studies published between 2019 and 2023 with 1927 participants were included. The present meta-analysis suggested that 1-day LRD was comparable with 3-day LRD for adequate bowel preparation (OR 0.89; 95% CI, 0.65-1.21; P = 0.45; I2 = 0%; P = 0.52). The polyp detection rate (OR 0.94; 95% CI, 0.77-1.14; P = 0.52; I2 = 23%; P = 0.27) and adenoma detection rate (OR 0.87; 95% CI, 0.71-1.08; P = 0.21; I2 = 0%; P = 0.52) were similar between the groups. There were significantly higher odds of tolerability in patients consuming 1-day LRD compared with 3-day LRD (OR 1.64; 95% CI, 1.13-2.39; P < 0.01; I2 = 47%; P = 0.15). In addition, constipation was identified as the independent predictor of inadequate preparation (OR 1.98; 95% CI, 1.27-3.11; P < 0.01; I2 = 0%; P = 0.46).

CONCLUSION

The present study demonstrated that a 1-day LRD was as effective as a 3-day CLD in the quality of bowel preparation before colonoscopy and significantly improved tolerability of patients. In addition, constipation is an independent risk factor of poor bowel preparation, and the duration of LRD in patients with constipation still needs further clinical trials.

Bowel preparation protocol for hospitalized patients ages 50 years or older: A randomized controlled trial

BACKGROUND

The incidence and mortality rate of colorectal cancer progressively increase with age and become particularly prominent after the age of 50 years. Therefore, the population that is ≥ 50 years in age requires long-term and regular colonoscopies. Uncomfortable bowel preparation is the main reason preventing patients from undergoing regular colonoscopies. The standard bowel preparation regimen of 4-L polyethylene glycol (PEG) is effective but poorly tolerated.

AIM

To investigate an effective and comfortable bowel preparation regimen for hospitalized patients ≥ 50 years in age.

METHODS

Patients were randomly assigned to group 1 (2-L PEG + 30-mL lactulose + a low-residue diet) or group 2 (4-L PEG). Adequate bowel preparation was defined as a Boston bowel preparation scale (BBPS) score of ≥ 6, with a score of ≥ 2 for each segment. Non-inferiority was prespecified with a margin of 10%. Additionally, the degree of comfort was assessed based on the comfort questionnaire.

RESULTS

The proportion of patients with a BBPS score of ≥ 6 in group 1 was not significantly different from that in group 2, as demonstrated by intention-to-treat (91.2% vs 91.0%, P = 0.953) and per-protocol (91.8% vs 91.0%, P = 0.802) analyses. Furthermore, in patients ≥ 75 years in age, the proportion of BBPS scores of ≥ 6 in group 1 was not significantly different from that in group 2 (90.9% vs 97.0%, P = 0.716). Group 1 had higher comfort scores (8.85 ± 1.162 vs 7.59 ± 1.735, P < 0.001), longer sleep duration (6.86 ± 1.204 h vs 5.80 ± 1.730 h, P < 0.001), and fewer awakenings (1.42 ± 1.183 vs 2.04 ± 1.835, P = 0.026) than group 2.

CONCLUSION

For hospitalized patients ≥ 50 years in age, the bowel preparation regimen comprising 2-L PEG + 30-mL lactulose + a low-residue diet produced a cleanse that was as effective as the 4-L PEG regimen and even provided better comfort.

One-Day versus Three-Day Low-Residue Diet and Bowel Preparation Quality before Colonoscopy: A Multicenter, Randomized, Controlled Trial

BACKGROUND

One-day low-residue diet (LRD) is recommended before colonoscopy, but only three single-center trials compared the 1-day versus 3-day LRD. The aim of this multicenter study was to compare the impact of a 3-day versus 1-day LRD on its ability to adequately and successfully prepare the bowel of outpatients that require a colonoscopy. The outpatients' tolerance and adherence to the LRD were also considered.

METHODS

Consecutive outpatients were randomized to 1-day versus 3-day LRD at three open-access endoscopy units. The primary endpoint consisted of the proportion of patients with a satisfactory degree of bowel cleanliness (Score 2-3 on the Boston Bowel Preparation Scale [BBPS] in each segment). Secondary endpoints were patients' tolerance and adherence to the prescribed diet evaluated by a standardized questionnaire.

RESULTS

289 patients were included in the study (1-day LRD arm = 143, 3-day LRD arm = 146). BBPS ≥2 was not significantly different in the two dietary regimens in any of the three colonic segments (71% vs. 72%, p = 0.9). The percentage of patients with incomplete preparation was similar in the two arms (9% vs. 9%; p = 1.0). No significant differences were found among colonoscopy findings in terms of abnormalities (81% vs. 84%, p = 0.8). Both groups scored similarly in overall tolerance to LRD (48% vs. 49%, p = 1.0) and also in whether they would have adopted a different dietary regimen (p = 0.3).

CONCLUSION

Our multicenter randomized study confirmed that optimal bowel cleansing is reached through a 1-day LRD.

Safe, efficient, and effective screening colonoscopy

PURPOSE OF REVIEW

Colorectal cancer continues to be one of the most common causes of cancer-related death. Widespread dissemination of screening colonoscopy in the United States has led to a significant reduction in the incidence and mortality. Here we review current literature with an aim to highlight recent improvements in the safety, efficiency, and effectiveness of screening colonoscopy.

RECENT FINDINGS

Colon capsule endoscopy is an emerging noninvasive method to capture images of colonic mucosa for select patients with appreciable sensitivity for polyp detection. Recent literature supports the use of the novel oral anticoagulant apixaban over other anticoagulants to reduce the risk of gastrointestinal bleeding related to colonoscopy. Cold snare polypectomy for smaller lesions and prophylactic clipping following resection of large polyps in the proximal colon may reduce the rate of delayed bleeding. Novel methods and devices for improving bowel preparation continue to emerge. Mechanical attachment devices and artificial intelligence represent recent innovations to improve polyp detection.

SUMMARY

Clinicians should be aware of relevant data and literature that continue to improve the quality and safety of screening colonoscopy and incorporate these findings into their clinical practice.

Effects of Different Intervention Methods on Intestinal Cleanliness in Children Undergoing Colonoscopy

Objective

To explore the effects of different intervention methods on intestinal cleanliness in children undergoing colonoscopy.

Methods

61 children who underwent colonoscopy in our hospital from May 2020 to May 2021 were randomly divided into group A (n = 21), group B (n = 30), and group C (n = 10). The children in the three groups were intervened in different ways before the colonoscopy. Group A received a long-handled Kaiselu +1 cathartic intervention, while group B received a long-handled Kaiselu +2 cathartic intervention, and group C received an enema plus one cathartic intervention. The patients in the three groups were given the same diet before the examination until the examination was completed. The time-related indexes, cleanliness, adverse reactions, tolerance, and adaptability of the three groups under different dietary interventions and cleaning methods were evaluated.

Results

The first defecation time in group C was lower than that in group A and group B, the hospital stay was longer than that in group A and group B (p > 0.05), and the colonoscopy time in group C was shorter than that in group A and group B (p < 0.05). The BBPS score of group C was (2.10 ± 0.32), which was significantly higher than that of group A (1.16 ± 0.19) and group B (1.77 ± 0.18) (p < 0.05). The BBPS scores of children with liquid food in the three groups were significantly higher than those of common food, and the BBPS scores of liquid food and common food in group C were significantly higher than those in group A and group B (p < 0.05). The incidence of adverse reactions in group C was 20.00%, which was significantly lower than 33.33% in group A and 23.33% in group B (p < 0.05). The proportion of grade I in group C was 50.00%, which was significantly higher than 38.10% in group A and 43.33% in group B (p < 0.05).

Conclusion

Children undergoing colonoscopy take preintestinal preparation under different diets and intervention methods. The cleanliness of liquid food and enema + one-time laxative one day before colonoscopy is the best, which can significantly reduce adverse reactions and increase the acceptability and adaptability of children. It is worthy of clinical application.

Novel frontiers of agents for bowel cleansing for colonoscopy

The incidence of colorectal cancer (CRC) is characterized by rapid declines in the wake of widespread screening. Colonoscopy is the gold standard for CRC screening, but its accuracy is related to high quality of bowel preparation (BP). In this review, we aimed to summarized the current strategy to increase bowel cleansing before colonoscopy. Newly bowel cleansing agents were developed with the same efficacy of previous agent but requiring less amount of liquid to improve patients’ acceptability. The role of the diet before colonoscopy was also changed, as well the contribution of educational intervention and the use of adjunctive drugs to improve patients’ tolerance and/or quality of BP. The review also described BP in special situations, as lower gastrointestinal bleeding, elderly people, patients with chronic kidney disease, patients with inflammatory bowel disease, patients with congestive heart failure, inpatient, patient with previous bowel resection, pregnant/lactating patients. The review underlined the quality of BP should be described using a validate scale in colonoscopy report and it explored the available scales. Finally, the review explored the possible contribution of bowel cleansing in post-colonoscopy syndrome that can be related by a transient alteration of gut microbiota. Moreover, the study underlined several points needed to further investigations.

Impact of Prepackaged Low-Residue Diet on Bowel Preparation for Colonoscopy: A Meta-analysis

This meta-analysis aimed to evaluate the impact of prepackaged low-residue diet (PLRD) on bowel preparation for colonoscopy. We searched PubMed, Web of Science, EMBASE, and Cochrane Library databases from inception to August 2020. Randomized controlled trials (RCTs) comparing PLRD with clear liquid diet (CLD) or self-prepared LRD were considered for inclusion. The analysis calculated the odds ratio (OR) for the rate of adequate bowel preparation, patient tolerance, willingness to repeat bowel preparation, tolerability of bowel preparation, and overall adverse effects. Five RCTs published between 2006 and 2019 (N = 561) were included in our meta-analysis. Compared with the traditional CLD or self-prepared LRD, PLRD showed significantly higher rates of adequate bowel preparation (OR, 2.16; 95% confidence interval [CI], 1.18-3.98; p = .01), patient tolerance (OR, 1.99; 95% CI, 1.30-3.07; p = .002), and willingness to repeat the bowel preparation (OR, 1.68; 95% CI, 1.05-2.70; p = .03), with no differences in adverse events (OR, 0.93; 95% CI, 0.59-1.46; p = .75). Prepackaged low-residue diet improved bowel preparation quality, patient tolerance, and willingness to repeat bowel preparations. Importantly, PLRD does not increase the incidence of adverse events. This suggests that it is effective and safe to use PLRD for bowel preparation before colonoscopy.