Sodium phosphate is superior to polyethylene glycol in constipated patients undergoing colonoscopy: a systematic review and meta-analysis

Constipation and colonoscopy

Constipation is a significant sociomedical problem, which can be caused by various reasons. In the diagnostic approach to patients with constipation, the following data are usually sufficient: History, complete physical examination (including rectal examination), and additional diagnostic tests. A colonoscopy is not a necessary diagnostic method for all patients with constipation. However, if patients have alarm symptoms/signs, that suggest an organic reason for constipation, a colonoscopy is necessary. The most important alarm symptoms/signs are age > 50 years, gastrointestinal bleeding, new-onset constipation, a palpable mass in the abdomen and rectum, weight loss, anemia, inflammatory bowel disease, and family history positive for colorectal cancer. Most endoscopists do not like to deal with patients with constipation. There are two reasons for this, namely the difficulty of endoscopy and the adequacy of preparation. Both are adversely affected by constipation. To improve the quality of colonoscopy in these patients, good examination techniques and often more extensive preparation are necessary. Good colonoscopy technique implies adequate psychological preparation of the patient, careful insertion of the endoscope with minimal insufflation, and early detection and resolution of loops. Bowel preparation for colonoscopy often requires prolonged preparation and sometimes the addition of other laxatives.

Comparison of oral sodium phosphate tablets and polyethylene glycol lavage solution for colonoscopy preparation: a systematic review and meta-analysis of randomized clinical trials

Objective

To systematically compare the bowel cleaning ability, patient tolerance and safety of oral sodium phosphate tablets (NaPTab) and oral polyethylene glycol electrolyte lavage solution (PEGL) to inform clinical decision making.

Methods

PubMed, Embase, CBM, WanFang Data, CNKI, and VIP databases were searched for studies that used randomized controlled trials (RCTs) to compare the roles of NaPTab and PEGL in bowel preparation before colonoscopy. Two reviewers independently screened the studies, extracted data, and assessed the risk of bias in the included papers. A meta-analysis was performed using RevMan 5.3 software.

Results

A total of 13 RCTs were eligible for inclusion, including 2,773 patients (1,378 and 1,395 cases in the NaPTab and PEGL groups, respectively). Meta-analysis revealed no significant difference in the cleansing quality of the NaPTab and PEGL groups [RR 1.02, 95% CI (0.96-1.08), P = 0.46]. The incidence of nausea was lower in the NaPTab group than in the PEGL group [RR 0.67, 95% CI (0.58-0.76), p < 0.00001]. Patients rated the taste of NaPTab higher than PEGL [RR 1.33, 95% CI (1.26-1.40), P < 0.00001]. Willingness to repeat the treatment was also higher in the NaPTab group than in the PEGL group [RR 1.52, 95% CI (1.28-1.80), P < 0.00001]. Both serum potassium and serum calcium decreased in both groups after the preparation; however, meta-analysis revealed that both minerals decreased more in the NaPTab group than in the PEGL group [MD = 0.38, 95% CI (0.13-0.62), P = 0.006 for serum potassium and MD = 0.41, 95% CI (0.04-0.77), P = 0.03 for serum calcium]. Meanwhile, serum phosphorus increased in both groups after the preparation; however, levels increased more in the NaPTab group than in the PEGL group [MD 4.51, (95% CI 2.9-6.11), P < 0.00001].

Conclusions

While NaP tablets and PEGL were shown to have a similar cleaning effect before colonoscopy, NaP tablets had improved patient tolerance. However, NaP tablets had a strong effect on serum potassium, calcium, and phosphorus levels. For patients with low potassium, low calcium, and renal insufficiency, NaP tablets should be prescribed with caution. For those at high-risk for acute phosphate nephropathy, NaP tablets should be avoided. Given the low number and quality of included studies, these conclusions will require additional verification by large high-quality studies.

Systematic review registration

10.37766/inplasy2023.5.0013, identifier: NPLASY202350013.

Factors affecting the quality of bowel preparation for colonoscopy in hard-to-prepare patients: Evidence from the literature

Adequate bowel cleansing is critical for a high-quality colonoscopy because it affects diagnostic accuracy and adenoma detection. Nevertheless, almost a quarter of procedures are still carried out with suboptimal preparation, resulting in longer procedure times, higher risk of complications, and higher likelihood of missing lesions. Current guidelines recommend high-volume or low-volume polyethylene glycol (PEG)/non-PEG-based split-dose regimens. In patients who have had insufficient bowel cleansing, the colonoscopy should be repeated the same day or the next day with additional bowel cleansing as a salvage option. A strategy that includes a prolonged low-fiber diet, a split preparation regimen, and a colonoscopy within 5 h of the end of preparation may increase cleansing success rates in the elderly. Furthermore, even though no specific product is specifically recommended in the other cases for difficult-to-prepare patients, clinical evidence suggests that 1-L PEG plus ascorbic acid preparation are associated with higher cleansing success in hospitalized and inflammatory bowel disease patients. Patients with severe renal insufficiency (creatinine clearance < 30 mL/min) should be prepared with isotonic high volume PEG solutions. Few data on cirrhotic patients are currently available, and no trials have been conducted in this population. An accurate characterization of procedural and patient variables may lead to a more personalized approach to bowel preparation, especially in patients undergoing resection of left colon lesions, where intestinal preparation has a poor outcome. The purpose of this review was to summarize the evidence on the risk factors influencing the quality of bowel cleansing in difficult-to-prepare patients, as well as strategies to improve colonoscopy preparation in these patients.

Association between dietary phosphorus intake and chronic constipation in adults: evidence from the National Health and Nutrition Examination Survey

BACKGROUND

Several studies suggest a link between micronutrients and constipation. However, the relationship between constipation and phosphorus has rarely been examined. The main aim of this study was to investigate the association between changes in the prevalence of chronic constipation and dietary phosphorus intake among adult respondents of the National Health and Nutritional Examination Survey (NHANES).

METHODS

Data were extracted from the NHANES database for the years 2005-2010. A total of 13,948 people were included in the analysis. Dietary information was collected using the respondents' 24-h dietary records. We conducted multiple logistic regression analyses to examine the correlation between phosphorus intake and poor bowel movement. The primary and secondary outcomes was constipation defined by stool consistency and stool frequency, respectively.

RESULTS

Following multi-variate adjustment in model III, a significant association between chronic constipation and each additional 0.1-g intake of dietary phosphorus (odds ratio [OR], 0.97; 95% confidence interval [CI], 0.95, 1.00; P = 0.034 for stool consistency vs. OR, 0.94; 95% CI, 0.90, 0.99; P = 0.027 for stool frequency) was observed. Following multi-variate adjustment in model III, OR values and 95% CI from the second to fourth quartiles compared to the first quartile (reference group) were 0.92 (0.66, 1.27), 0.73 (0.47, 1.13), and 0.39 (0.20, 0.76), respectively, using the stool frequency definition.

CONCLUSIONS

This study revealed a negative correlation between phosphorus intake and chronic constipation. This may be due to the fact that dietary phosphorus intake is associated with softer stools and increased stool frequency. Further studies in different settings should be considered to verify these findings.

Factors Affecting the Quality of Bowel Preparation Before Colonoscopy in Outpatient: A Prospective Observational Study

Colonoscopy is an effective method for screening colorectal cancer and adenoma, but the adenoma detection rate depends on the quality of bowel preparation. Our study investigates the influencing factors of the quality of bowel preparation before colonoscopy in outpatients and the influence of the number of walking steps on the quality of bowel preparation. We prospectively collected the clinical data of 150 outpatients undergoing colonoscopy in our department in 2019. Ordinal logistic regression shows that the overweight, not drinking, the number of walking steps before colonoscopy, and the time interval between start PEG and colonoscopy (4-6 hours) were independent factors affecting bowel preparation quality. There was a curving relationship between the reciprocal of Ottawa score and the number of walking steps before colonoscopy, and the regression equation is 1/ Ottawa score = -0.198 + 0.062 × ln steps (p = .035), a minimum of 5,270 walking steps before a colonoscopy is required for a high quality of bowel preparation.

The Efficacy of Senna Bowel Preparation for Colonoscopy: A Systematic Review and Meta-analysis

The quality of bowel preparation is an extremely important determinant of colonoscopy results. However, the efficacy of senna regimens in improving bowel cleanliness is uncertain. We conducted a systematic review and meta-analysis to synthesize data on whether using a senna bowel preparation regimen enhances the bowel cleanliness. We searched Web of Science Core Collection, MEDLINE, PubMed, Embase, Cochrane Library, and Scopus databases (from the inception to August 2021). The primary efficacy outcome was bowel cleanliness. Secondary outcomes included patient compliance, tolerance, and adverse events. Eleven trials fulfilled the inclusion criteria (3,343 patients. Overall, we found no significant differences in bowel cleanliness between the senna regimen and other bowel preparation regimens (odds ratio [95% confidence interval]: 1.02 [0.63, 1.67], p = 0.93). There was significant difference in tolerance (odds ratio [95% confidence interval]: 1.66 [1.08, 2.54], p = .02) and compliance (odds ratio [95% confidence interval]: 3.05 [1.42, 6.55], p = .004). The senna regimen yielded a significantly greater proportion of no nausea (odds ratio [95% confidence interval]: 1.84 [1.45, 2.32]) and vomiting (odds ratio [95% confidence interval]: 1.65 [0.81, 3.35]). Compared with other bowel preparation regimens, the senna regimen may be effective and safe in bowel cleaning before colonoscopy, with superior compliance and tolerance.

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.

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.