Oral sodium phosphate solution is a superior colonoscopy preparation to polyethylene glycol with bisacodyl

Predictors and colonoscopy outcomes of inadequate bowel cleansing: a 10-year experience in 28,725 patients

BACKGROUND

Inadequate bowel preparation is still the main obstacle to a complete colonoscopy in many patients and necessitates many repeated procedures. We aimed to identify risk factors associated with inadequate bowel preparation and to better characterize these patients.

METHODS

This was a retrospective study that reviewed electronic reports of colonoscopy procedures over a 10-year period. Patients were divided into 2 groups: adequate vs. non-adequate bowel preparation. A multivariate analysis was performed to identify variables associated with inadequate bowel preparation, including age, sex, setting (inpatient/outpatient), preparation regimen and procedures' indications. We examined the effect of inadequate preparation on colonoscopy quality indicators.

RESULTS

Of the 28,725 patients included in the study, 6,702 (23.3%) had inadequate bowel preparation. In the multivariate analysis, advanced age (odds ratio [OR] 1.015, 95% confidence interval [CI] 1.013-1.017; P<0.01), male sex (OR 1.353, 95%CI 1.286-1.423; P<0.01) and a minority population (OR 1.635, 95%CI 1.531-1.746; P<0.01) were significantly associated with inadequate bowel preparation. The inpatient setting was among the most prominent factors associated with inadequate bowel preparation (OR 2.018, 95%CI 1.884-2.163; P<0.01). Adequate bowel preparation was associated with a higher polyp detection rate (26.8% vs. 23.6%; OR 1.22, 95%CI 1.109-1.347; P<0.01) and colorectal cancer (2.8% vs. 2.4%; OR 1.402, 95%CI 1.146-1.716; P<0.01), and higher frequencies of cecal (96.4% vs. 73.5%; OR 2.243, 95%CI 2.095-2.403; P<0.01) and terminal ileum intubation (8.1% vs. 5.4%; OR 1.243, 95%CI 1.088-1.434; P<0.01).

CONCLUSION

We outlined various factors associated with inadequate bowel preparation and confirmed its adverse effect on colonoscopy quality indicators.

Mechanical colon cleansing for screening colonoscopy: A randomized controlled trial

OBJECTIVE

Effective screening colonoscopy depends on the quality of colon preparation. This study aimed to compare pulsed irrigation evacuation (PIE), polyethylene glycol (PEG) and sodium phosphate colon preparations.

METHODS

Outpatients at a VA hospital were randomized using sealed envelopes. Preparations consisted of polyethylene glycol 4L, Fleet sodium phosphate 90 mL with four to six glasses water twice daily and 296 mL of magnesium citrate in the evening with PIE prior to colonoscopy. Colon cleansing was assessed blindly using a five-point scale: 0 (very poor) to 4 (excellent).

RESULTS

Altogether 391 patients participated in the study (129 in the PEG group, 127 in the sodium phosphate and 135 in the PIE group), with a mean age of 62 years, of whom 75% were men. PIE and sodium phosphate were superior to PEG: median cleansing scored 4 (excellent) versus 3 with PEG (P < 0.01). Inadequate preparations were more common with PEG than PIE (18% vs 5%) (P < 0.01). Side-effects included vomiting: 37% in the sodium phosphate group versus 5% in the PEG and 2% in the PIE groups (P < 0.01). The three preparations were judged intolerable in ≤ 5%.

CONCLUSIONS

PIE and sodium phosphate are superior to PEG for colon preparations. PIE is the preferred preparation for those at high risk of unsatisfactory preparations or with unsatisfactory traditional preparations.

Phase II Randomized Controlled Trial of Combined Oral laxatives Medication for BOwel PREParation (COMBO-PREP study)

The combination of different laxatives at reduced volumes may benefit patients by enhancing efficacy for bowel cleansing and increasing tolerability. However, evidence regarding combined preparations is scarce. This study evaluated whether the combined preparations are associated with enhanced efficacy and tolerability. This randomized phase II study had a single-blind, parallel-arm design. Between December 2013 and September 2014, consecutive patients aged between 20 and 65 years and who required diagnostic colonoscopies were considered for inclusion. Patients were randomly allocated into 4 arms: sodium picosulfate and magnesium citrate (PMC) and polyethylene glycol (PEG) with ascorbic acid in a day-prior (PMC-PEG-DP), PMC and oral sodium phosphate (NaP) in a day-prior (PMC-NaP-DP), PMC and PEG with ascorbic acid in a split-dose (PMC-PEG-SD), and PMC and oral NaP in a split-dose (PMC-NaP-SD). Primary endpoint was the Aronchick scale, and Ottawa scale results by colon segment, patients' adverse gastrointestinal symptoms, and willingness to reuse the same agents were also recorded. Successful bowel preparation was defined as an "excellent" or "good" score on the Aronchick scale. A total of 236 patients were randomized and 229 patients received the planned colonoscopy. The rates of successful bowel preparation in the PMC-PEG-DP, PMC-NaP-DP, PMC-PEG-SD, and PMC-NaP-SD were 82.5%, 64.4%, 100%, and 100%, respectively. Excluding the failed PMC-NaP-DP group, all groups showed satisfactory rates of successful bowel preparation, and the mean Ottawa scores were significantly better in the PMC-PEG-SD and PMC-NaP-SD groups than in the PMC-PEG-DP group (P < 0.0001). The PMC-PEG-DP, PMC-NaP-DP, PMC-PEG-SD, and PMC-NaP-SD groups were similar in terms of rates of adverse gastrointestinal symptoms reported on a 5-point scale (P = 0.40) and willingness to reuse the same combined preparations (P = 0.55). PMC-PEG in a day-prior or split-dose and PMC-NaP in a split-dose were efficient and tolerable bowel preparations for colonoscopy.

Comparison between pulsed irrigation enhanced evacuation and polyethylene glycol-electrolyte lavage solution for bowel preparation prior to elective colonoscopy in veterans with spinal cord injury

BACKGROUND

Poor preparation for elective colonoscopy is common in persons with spinal cord injury (SCI). This unsatisfactory outcome is likely due to long-standing difficulty with evacuation and decreased colonic motility. Our objective was to determine the most effective preparation for elective colonoscopy applying a novel and traditional approach to bowel cleansing.

METHODS

Twenty-four subjects with SCI were consented and scheduled to receive one of the two possible arms: pulsed irrigation enhanced evacuation (PIEE) or polyethylene glycol-electrolyte lavage solution (PEG; CoLyte(®)). The quality of the preparation was scored during the colonoscopy by applying the Ottawa scoring system.

RESULTS

Patients with SCI who received PIEE tended to have lower Ottawa scores and a higher percentage of acceptable preparations than did those who received PEG; however, the results were not statistically different.

CONCLUSION

In this preliminary study in subjects with SCI, neither PIEE nor PEG produced acceptable bowel preparation for elective colonoscopy. Future studies should confirm our findings and consider studying alternative, more efficacious approaches to bowel cleansing prior to colonoscopic procedures in patients with SCI, which should provide better outcomes. Registration number for clinicaltrials.gov: NCT00745095.

Neostigmine Administered With MoviPrep Improves Bowel Preparation for Elective Colonoscopy in Patients With Spinal Cord Injury: A Randomized Study

BACKGROUND

Poor preparation for elective colonoscopy is exceedingly common in persons with spinal cord injury (SCI). This unsatisfactory outcome is likely due to long-standing difficulty with evacuation and decreased colonic motility, which may result in inadequate responses to conventional bowel preparation regimens. We determined whether the addition of neostigmine to MoviPrep before elective colonoscopy produced a higher percentage of acceptable bowel preparations in patients with SCI.

METHODS

Twenty-seven SCI subjects were prospectively randomized to 1 of 2 arms: low-volume polyethylene glycol-electrolyte lavage with ascorbic acid (MoviPrep) or MoviPrep plus neostigmine methylsulfate and glycopyrrolate (MoviPrep+NG); 28 able-bodied subjects received MoviPrep alone. The quality of the cleansing preparation for colonoscopy was determined by gastroenterologists "calibrated" to use the Ottawa Scoring System, with an acceptable Ottawa Score (OS) considered to be ≤3.

RESULTS

The administration of MoviPrep alone resulted in suboptimal bowel cleansing in the SCI group compared with the able-bodied group (50% vs. 89% of subjects had an acceptable OS; χ=7.94, P=0.05). However, when NG was added to MoviPrep in the SCI group, it markedly improved the quality of the bowel preparation, with 85% of patients then having an acceptable OS. The use of NG resulted in minimal bloating and distention before bowel evacuation (P=0.0005), and eye and muscle twitching; these were resolved within 1 hour after NG administration. No significant differences were noted among the preparation groups for adenoma detection rate (P=0.41).

CONCLUSIONS

The combination of MoviPrep+NG was safe, well tolerated, and an effective approach to prepare the bowel for elective colonoscopy in patients with SCI. The side effects of this preparation were significant compared with the other treatment groups but were considered mild and anticipated.

Split-Dose Preparations Are Superior to Day-Before Bowel Cleansing Regimens: A Meta-analysis

BACKGROUND & AIMS

There are different regimens of preparing the colon for colonoscopy, including polyethylene glycol (PEG), sodium phosphate, picosulfate, or oral sulfate solutions. We performed a meta-analysis to determine the efficacy of split-dose vs other colon preparation regimens, the optimal products for use, and the most effective preparation volumes.

METHODS

We performed systematic searches of MEDLINE, EMBASE, Scopus, CENTRAL, and ISI Web of knowledge databases, from January 1980 to March 2014, for published results from randomized trials that assessed split-dose regimens vs day-before colonoscopy preparation. We excluded studies that included pediatric or hospitalized patients, or patients with inflammatory bowel disease. The primary outcome was efficacy of bowel cleansing. Secondary outcomes included side effects or complications, outcomes of procedures, patients' willingness to repeat the procedure, and the amount of time required for patients to resume daily activities.

RESULTS

We identified 47 trials that fulfilled our inclusion criteria (n = 13,487 patients). Split-dose preparations provided significantly better colon cleansing than day-before preparations (odds ratio [OR], 2.51; 95% confidence interval, 1.86-3.39), as well as day-before preparations with PEG (OR, 2.60; 95% confidence interval, 1.46-4.63), sodium phosphate (OR, 9.34; 95% confidence interval, 2.12-41.11), or picosulfate (OR, 3.54; 95% confidence interval, 1.95-6.45). PEG split-dose preparations of 3 L or more yielded greater bowel cleanliness than lower-volume split-dose regimens (OR, 1.89; 95% confidence interval, 1.01-3.46), but only in intention-to-treat analysis. A higher proportion of patients were willing to repeat split-dose vs day-before cleansing (OR, 1.90; 95% confidence interval, 1.05-3.46), and low-volume split-dose preparations vs high-volume split-dose preparation (OR, 4.95; 95% confidence interval, 2.21-11.10). There were no differences between preparations in other secondary outcome measures. However, there was variation among studies in definitions and main and secondary outcomes.

CONCLUSIONS

Based on meta-analysis, split-dose regimens increase the quality of colon cleansing and are preferred by patients compared with day-before preparations. Additional research is required to evaluate oral sulfate solution-based and PEG low-volume regimens further.

Optimal bowel cleansing for colonoscopy: split the dose! A series of meta-analyses of controlled studies

BACKGROUND

Colonoscopy is considered the criterion standard for detecting colorectal cancer; adequate preparation is crucial for an effective colonoscopy, but definitive data on the optimal preparation are lacking.

OBJECTIVE

Our aim was to assess the efficacy of split-dose versus non-split-dose preparations, the rate of adequate preparation according to type and dose of laxatives, the role of "runway time" (the interval time between the last drink of purgative and the beginning of colonoscopy), and to evaluate compliance as an additive risk factor for colon cleansing.

DESIGN

A series of meta-analyses of controlled studies.

SETTING

Randomized clinical trial of split dose regimen versus entire dose taken on the day preceding colonoscopy.

PATIENTS

Published trials (1960-2013) comparing split-dose versus non-split-dose preparations in adults undergoing colonoscopy were selected by using MEDLINE, the Cochrane Central Register of Controlled Trials, clinicaltrial.gov, ISI Web of Science, and Scopus.

INTERVENTIONS

Colonoscopy.

MAIN OUTCOME MEASUREMENTS

Rate difference of the degree of colon cleansing between split dose and whole dose was the primary measure of treatment effect.

RESULTS

We included 29 studies. Overall, an adequate preparation was obtained in 85% of patients in the split-dose group and in 63% of the non-split-dose group (rate difference 22%). The heterogeneity was caused by 5 factors: the runway time (the longer, the worse the cleansing), type of diet, male sex, use of polyethylene glycol 4 L, and the Jadad score. Compliance was significantly higher in the split-dose group.

LIMITATIONS

Average quality of the included studies and publication bias.

CONCLUSION

We provided further evidence of the superiority of a split-dose regimen over a non-split-dose regimen and showed that, regardless of type and dose, the superiority of split-dose regimens remains valid if the "golden 5 hours" rule is preserved.

A meta-analysis of randomized controlled trials of low-volume polyethylene glycol plus ascorbic acid versus standard-volume polyethylene glycol solution as bowel preparations for colonoscopy

BACKGROUND

Standard-volume polyethylene glycol (PEG) gut lavage solutions are safe and effective, but they require the consumption of large volumes of fluid. A new lower-volume solution of PEG plus ascorbic acid has been used recently as a preparation for colonoscopy.

AIM

A meta-analysis was performed to compare the performance of low-volume PEG plus ascorbic acid with standard-volume PEG as bowel preparation for colonoscopy.

STUDY

Electronic and manual searches were performed to identify randomized controlled trials (RCTs) that compared the performance of low-volume PEG plus ascorbic acid with standard-volume PEG as bowel preparation for colonoscopy. After a methodological quality assessment and data extraction, the pooled estimates of bowel preparation efficacy during bowel cleansing, compliance with preparation, willingness to repeat the same preparation, and the side effects were calculated. We calculated pooled estimates of odds ratios (OR) by fixed- and/or random-effects models. We also assessed heterogeneity among studies and the publication bias.

RESULTS

Eleven RCTs were identified for analysis. The pooled OR for preparation efficacy during bowel cleansing and for compliance with preparation for low-volume PEG plus ascorbic acid were 1.08 (95% CI = 0.98-1.28, P = 0.34) and 2.23 (95% CI = 1.67-2.98, P<0.00001), respectively, compared with those for standard-volume PEG. The side effects of vomiting and nausea for low-volume PEG plus ascorbic acid were reduced relative to standard-volume PEG. There was no significant publication bias, according to a funnel plot.

CONCLUSIONS

Low-volume PEG plus ascorbic acid gut lavage achieved non-inferior efficacy for bowel cleansing, is more acceptable to patients, and has fewer side effects than standard-volume PEG as a bowel preparation method for colonoscopy.

Effects of the addition of high-dose vitamin C to polyethylene glycol solution for colonic cleansing: A pilot study in healthy volunteers

BACKGROUND

Polyethylene glycol (PEG) solutions, with or without osmotic agents, are used to empty the large intestine before procedures such as colonoscopy or colonic surgery. Data concerning the effectiveness of vitamin C as an ingredient in colonic preparations are scant.

OBJECTIVE

The aim of this article was to assess the effectiveness, acceptability, and tolerability of 6 preparations of a standard PEG electrolyte solution containing different doses of PEG, vitamin C (as an osmotic agent), and sodium sulfate in colonic cleansing.

METHODS

This double-blind, randomized, 2-period crossover study was conducted at the Lariboisière Hospital, Paris, France. Healthy adult volunteers were randomly assigned to receive 2 of 6 colonic cleansing preparations, each containing different doses of PEG (100 or 125 g/L), vitamin C (0, 5, or 10 g/L, in the form of sodium ascorbate, ascorbic acid, or a mixture of both), and sodium sulfate (5 or 7.5 g/L), diluted in water to a volume of 2 L. Study drug administration was separated by a washout period of 7 to 15 days, after which the volunteers received an alternate preparation. Stools were collected for 10 hours after the start of solution ingestion. The primary efficacy end point was stool volume. Secondary end points included acceptability of taste, assessed using a 100-mm visual analog scale (VAS) (0 = excellent to 100 = execrable), taste criteria (saltiness, acidity, and sweetness, assessed on a 4-point Likert-type scale [0 = very pleasant to 3 = intolerable]) and tolerability (clinical effects [changes in body weight, blood pressure, heart rate, and nausea and vomiting] and biologic effects [changes in serum electrolytes, creatinine, hematocrit, and ascorbic acid]).

RESULTS

Thirty volunteers (15 men, 15 women; mean [SD] age, 29.8 [8.2] years [range, 20-45 years]) were enrolled and completed the study. Mean (SD) stool volume obtained with preparations containing 10 g/L of vitamin C did not differ significantly from the volume obtained without vitamin C (2.54 [0.54] L vs 1.93 [0.62] L; 95% CI, -0.13 to 1.47). Mean (SD) VAS scores for acceptability of taste ranged from 54.4 (25.0) (preparation E) to 74.4 (20.1) (preparation C) (P = 0.03 preparation E vs all other preparations). The only significant difference in taste criteria was in acidity, with preparation A being the least acidic according to patients' ratings on the VAS (1.4 [0.7] vs 1.8 [0.4] [mean of the other 5 preparations combined]; P = 0.04 preparation A vs all other preparations). Mild dehydration occurred in 6 subjects (1 for each preparation). No clinical or biological adverse effects were found.

CONCLUSIONS

In this study of 6 colonic cleansing preparations in healthy volunteers, the use of high-dose vitamin C as an osmotic agent in addition to PEG did not significantly increase stool output. All 6 preparations were well tolerated.

2 L PEG plus ascorbic acid versus 4 L PEG plus simethicon for colonoscopy preparation: a randomized single-blind clinical trial

BACKGROUND

The 2 L polyethylene glycol (PEG) lavage solution has been proved to be similarly safe and effective as 4 L PEG formulations, in spite of the reduced volume.

OBJECTIVE

To compare low-volume PEG-based solution combined with ascorbic acid with high-volume PEG-based solution combined with simethicon in terms of efficacy and patient tolerability.

METHODS

This was a single-blind prospective randomized trial. Patients were randomized to receive either 2 L PEG plus ascorbic acid (PEG+Asc) or 4 L PEG plus simethicon (PEG+Sim). The primary endpoint was overall colon cleansing evaluation, assessed by blinded investigators using Aronchick score. Secondary end points included patient compliance and tolerability and adverse events.

RESULTS

Sixty patients received PEG+Asc and 60 received PEG+Sim. Overall bowel cleansing score was considered adequate in 81.67% of the PEG+Asc and 80% of the PEG+Sim groups, respectively. Excellent and good ratings were recorded in 11.6% and 38.3% receiving PEG+Asc as compared with 26.6% and 23.3% of patients receiving PEG+Sim. Patient tolerability and safety were similar with both the preparations.

CONCLUSIONS

According to our data, low-volume PEG+Asc has comparable efficacy, safety, and tolerability as high-volume PEG+Sim; therefore, it can be considered as a good alternative solution for bowel preparation. More improvements are necessary to achieve the target of a perfect preparation.

Sugar-free menthol candy drops improve the palatability and bowel cleansing effect of polyethylene glycol electrolyte solution

BACKGROUND

Colon preparations are generally poorly tolerated.

OBJECTIVE

To study the efficacy of sugar-free candy drops in improving palatability and tolerability of polyethylene glycol electrolyte solution (PEG-E).

DESIGN

Single-blind, randomized, controlled trial.

SETTING

University medical center.

PATIENTS

Ambulatory patients scheduled for elective colonoscopy.

INTERVENTION

Menthol candy drops. Patients were randomly assigned to split-dose, 4-L, PEG-E ± cough drops. Palatability was assessed on a linear scale of 1 to 5 (1 = disgusting; 5 = tasty). Quality of preparation, remaining unconsumed volume, and side effects were secondary outcomes.

MAIN OUTCOME MEASUREMENTS

Palatability and tolerability of PEG-E.

RESULTS

A total of 99 patients were enrolled (50 control group, 49 candy drops-added group). The mean (± standard deviation) palatability score was significantly better in candy drop users versus controls (3.9 ± 0.7 vs 2.8 ± 1.2, respectively; P < .001) as were the preparations scored as excellent (63.3% vs 34% of controls; P = .004). Side effects were similar except for nausea (24.5% candy drops vs 44% controls; P = .04). The amount of unconsumed PEG-E was not different between candy drop and control groups (128 [± 361 mL] versus 69 [± 194 mL], respectively; P = .32) but was significantly lower in excellent grade preparations versus other grades (31 [± 103 mL] versus 162 [± 384 mL], respectively; P = .024). On multivariate logistic regression, an excellent preparation was associated with candy drops (odds ratio [OR] 3.3, 95% confidence interval [CI], 1.4-7.8; P = .006) and smaller unconsumed volume of same-day PEG-E [OR 0.996, 95% CI, 0.992-1.000; P = .044).

LIMITATIONS

Single-center study.

CONCLUSION

Sugar-free menthol candy drops are a safe and effective addition to split-dose PEG-E, resulting in improved tolerability and patient compliance, which appears to translate into improved bowel cleansing. (

CLINICAL TRIAL REGISTRATION NUMBER

NCT01541683.).

The modern bowel preparation in colonoscopy

Adequate bowel preparation is essential for optimal colonoscopy. Suboptimal bowel preparation occurs in 25% to 40% of cases and is associated with canceled procedures, prolonged procedure time, incomplete examination, increased cost, and missed pathology. There are several effective formulations for colon cleansing with a good safety profile. Split dosing should be implemented whenever possible in an effort to enhance tolerance and adherence, and improve mucosal visibility and overall quality of the examination. In this review, modern bowel preparations are discussed including their mechanism of action, mode of use, safety, and how to optimize outcomes.

[Comparison among conventional 4 L polyethylene glycol, split method of 4 L polyethylene glycol and combination of 2 L polyethylene glycol and sodium phosphate solution for colonoscopy preparation]

BACKGROUND/AIMS

The aim of this study was to compare polyethylene glycol (PEG) 4 L, split method of PEG 4 L and PEG 2 L plus sodium phosphate (NaP) in the aspect of bowel preparation quality, safety, patients' compliance and preference.

METHODS

Total 249 subjects were prospectively enrolled and received bowel preparation for colonoscopy from August to October in 2010; PEG 4 L (93 subjects), split method of 4 L PEG (74 subjects) and PEG 2 L plus NaP 90 mL group (82 subjects). To investigate the completion, preference for bowel preparation and safety, a questionnaire survey was conducted before colonoscopy.

RESULTS

There were no significant intergroup differences in the aspect of completion of preparation, cecal intubation time and success rate. Satisfaction and preference were higher in PEG 2 L plus NaP 90 mL and split method of 4 L PEG compared with PEG 4 L. In the aspect of the bowel preparation quality PEG 4 L showed significantly higher quality in the morning colonoscopy (p<0.001). However, in the afternoon colonoscopy PEG 2 L plus NaP 90 mL showed better result than PEG 4 L (p=0.009). Hyperphosphatemia was most frequently observed in PEG 2 L plus NaP 90 mL, but no severe adverse events occurred (p<0.001).

CONCLUSIONS

PEG 4 L showed better result than split method of 4 L PEG or PEG 2 L plus NaP 90 mL in the aspect of bowel preparation quality and safety.

Meta-analysis: the relative efficacy of oral bowel preparations for colonoscopy 1985-2010

BACKGROUND

Previous reviews of bowel preparation for colonoscopy have given contradictory answers.

AIM

To provide a definitive insight, using PRISMA-compliant methodology.

METHODS

A comprehensive literature review identified randomised controlled trials comparing bowel preparation regimens. Data for quality of bowel preparation were pooled in multiple meta-analyses exploring a range of inclusion criteria.

RESULTS

A total of 104 qualifying studies were identified, the majority of which involved comparisons of sodium phosphate (NaP) or polyethylene glycol (PEG). There was no significant difference demonstrated between NaP and PEG overall (OR = 0.82; 95% CI = 0.56-1.21; P = 0.36). Cumulative meta-analysis demonstrated that this conclusion has been qualitatively similar since the mid 1990s, with little quantitative change for the past 10 years. Amongst studies with previous day dosing in both study arms there was a significant advantage in favour of PEG (OR = 1.78; 95% CI = 1.13-2.81; P = 0.006). Studies focussing on results in the proximal colon also favoured PEG (OR = 2.36; 95% CI = 1.16-4.77; P = 0.012). PEG was also significantly more effective than non-NaP bowel preparation regimens (OR = 2.02; 95% CI = 1.08-3.78; P = 0.03). Other comparisons showed no significant difference between regimens.

CONCLUSIONS

Although there is no compelling evidence favouring either of the two most commonly used bowel preparation regimens, this may reflect shortcomings in study design. Where studies have ensured comparable dosage, or the clinically relevant outcome of proximal bowel clearance is considered, PEG-based regimens offer the most effective option.

Low-volume plus ascorbic acid vs high-volume plus simethicone bowel preparation before colonoscopy

AIM: To investigate the effectiveness of low-volume plus ascorbic acid [polyethylene glycol plus ascorbic acid (PEG + Asc)] and high-volume plus simethicone [polyethylene glycol plus simethicone (PEG + Sim)] bowel preparations.

METHODS: A total of one hundred and forty-four outpatients (76 males), aged from 20 to 84 years (median age 59.5 years), who attended our Department, were divided into two groups, age and sex matched, and underwent colonoscopy. Two questionnaires, one for patients reporting acceptability and the other for endoscopists evaluating bowel cleansing effectiveness according to validated scales, were completed. Indications, timing of examination and endoscopical findings were recorded. Biopsy forceps were used as a measuring tool in order to determine polyp endoscopic size estimation. Difficulty in completing the preparation was rated in a 5-point Likert scale (1 = easy to 5 = unable). Adverse experiences (fullness, cramps, nausea, vomiting, abdominal pain, headache and insomnia), number of evacuations and types of activities performed during preparation (walking or resting in bed) were also investigated.

RESULTS: Seventy-two patients were selected for each group. The two groups were age and sex matched as well as being comparable in terms of medical history and drug therapies taken. Fourteen patients dropped out from the trial because they did not complete the preparation procedure. Ratings of global bowel cleansing examinations were considered to be adequate in 91% of PEG + Asc and 88% of PEG + Sim patients. Residual Stool Score indicated similar levels of amount and consistency of residual stool; there was a significant difference in the percentage of bowel wall visualization in favour of PEG + Sim patients. In the PEG + Sim group, 12 adenomas ≤ 10 mm diameter (5/left colon + 7/right colon) vs 9 (8/left colon + 1/right colon) in the PEG + Asc group were diagnosed. Visualization of small lesions seems to be one of the primary advantages of the PEG + Sim preparation.

CONCLUSION: PEG + Asc is a good alternative solution as a bowel preparation but more improvements are necessary in order to achieve the target of a perfect preparation.

Efficacy and tolerability of split-dose PEG compared with split-dose aqueous sodium phosphate for outpatient colonoscopy: a randomized, controlled trial

BACKGROUND AND AIMS

Adequate bowel cleansing is essential for a high-quality, effective, and safe colonoscopy. The aims of this study were to compare the efficacy and tolerability of split-dose polyethylene glycol with aqueous sodium phosphate for outpatients who underwent scheduled colonoscopy.

METHODS

In this prospective trial, 207 outpatients (aged between 18 and 65 years, with normal renal function, at low risk for renal damage) were randomized to receive split-dose preparation of PEG (2 L/2 L) (N = 103) or NaP (45 mL/45 mL, 12 h apart) (N = 104) without strict diet restriction the day before colonoscopy. The bowel cleansing efficacy of preparations was rated according to the Ottawa scale and the patient tolerability was assessed using a patient questionnaire.

RESULTS

There was no significant difference between the two groups for the mean total score using the Ottawa bowel preparation scale (P = 0.181). Significantly greater residual colonic fluid was observed in the split-dose PEG group (1.24 ± 0.49) than in the NaP group (1.04 ± 0.53) (P = 0.007). Patient compliance, preference, and acceptance of a two preparation regimen were similar with no significant differences (P = 0.095, P = 0.280 and P = 0.408, respectively). The overall incidence of adverse events was not significantly different between the two groups; however, the split-dose PEG group tended to have fewer adverse events (52/103 [50.5%], 66/104 [63.5%], P = 0.059) and had significantly less nausea and vomiting (P = 0.036).

CONCLUSIONS

Split-dose PEG, compared with split-dose NaP, is associated with more residual colonic fluid, but produces equivalent colon cleansing efficacy and results in less nausea and vomiting, which might improve patient tolerability (clinical trial registration number NCT01229800).

Bowel Preparation for Colonoscopy with Sodium Phosphate Solution versus Polyethylene Glycol-Based Lavage: A Multicenter Trial

BACKGROUND

Adequate bowel preparation is essential for accurate colonoscopy. Both oral sodium phosphate (NaP) and polyethylene glycol-based lavage (PEG-ELS) are used predominantly as bowel cleansing modalities. NaP has gained popularity due to low drinking volume and lower costs. The purpose of this randomized multicenter observer blinded study was to compare three groups of cleansing (NaP, NaP + sennosides, PEG-ELS + sennosides) in reference to tolerability, acceptance, and cleanliness.

PATIENT AND METHODS

355 outpatients between 18 and 75 years were randomized into three groups (A, B, C) receiving NaP = A, NaP, and sennosides = B or PEG-ELS and sennosides = C. Gastroenterologists performing colonoscopies were blinded to the type of preparation. All patients documented tolerance and adverse events. Vital signs, premedication, completeness, discomfort, and complications were recorded. A quality score (0-4) of cleanliness was generated.

RESULTS

The three groups were similar with regard to age, sex, BMI, indication for colonoscopy, and comorbidity. Drinking volumes (L) (A = 4.33 + 1.2, B = 4.56 + 1.18, C = 4.93 + 1.71) were in favor of NaP (P = .005). Discomfort from ingested fluid was recorded in A = 39.8% (versus C: P = .015), B = 46.6% (versus C: P = .147), and C = 54.6%. Differences in tolerability and acceptance between the three groups were statistically not significant. No differences in adverse events and the cleanliness effects occurred in the three groups (P = .113). The cleanliness quality scores 0-2 were calculated in A: 77.7%, B: 86.7%, and C: 85.2%.

CONCLUSIONS

These data fail to demonstrate significant differences in tolerability, acceptance, and preparation quality between the three types of bowel preparation for colonoscopy. Cleansing with NaP was not superior to PEG-ELS.

Polyethylene glycol vs. sodium phosphate for bowel preparation: a treatment arm meta-analysis of randomized controlled trials

Background

Results of meta-analyses of randomized trials comparing PEG and NaP are inconsistent and have not included trials comparing either or both preps to less traditional ones.

AIM: To perform a meta-analysis by treatment arm.

Methods

Using MEDLINE and EMBASE, we identified English-language trials published from 1990 to 2008 that included PEG and/or NaP, and aggregated them by treatment arm into: 4 liter (L) PEG; 2 L PEG; split-dose PEG; two 45 ml doses of NaP +/- adjunctive medication; and NaP tablets. We compared prep quality and the proportion completing the prep.

Results

Among 71 trials (patient N = 10,201), excellent prep quality was present in 34% (CI, 26-41%) for 4 L PEG alone; 39% (CI, 26-51%) for 2 L PEG; 37% (CI, 28-46%) for split-dose PEG; 42% (CI, 33-51%) for NaP solution; 44% (CI, 38-51%) for NaP with adjunctive meds; and 58% (CI, 49-67%) for NaP tablets. Patients receiving NaP were more likely to complete the prep (97% [CI, 96-98%] vs. 90% [CI, 87-92%] for 4L PEG alone); however, completion rates for 2L PEG (98%) and split dose PEG (95%) were similar to NaP.

Conclusions

NaP tablets resulted in better prep quality and higher completion rates compared to other regimens. In comparisons limited by sample size, split dose PEG was not statistically different from NaP solution for completion rate or prep quality.

Efficacy and safety of sodium phosphate for colon cleansing in type 2 diabetes mellitus

OBJECTIVES

The need for colonoscopy is common among diabetic patients. However, there are no standards per se for bowel preparation in patients with type 2 diabetes. In this study, we evaluated the efficacy, safety, and tolerability of sodium phosphate (NaP), and the quality of bowel cleansing in relation to glycemic control and late complications.

METHODS

A total of 50 consecutive type 2 diabetic patients and 50 non-diabetic patients underwent bowel preparation by NaP. Fasting blood glucose, sodium (Na), potassium (K), calcium (Ca), phosphorus (P), magnesium, and creatinine levels were measured on the procedure day. Patients were given a tolerability questionnaire regarding symptoms.

RESULTS

With regard to bowel preparation quality, optimal bowel cleansing was achieved in 35 (70%) diabetic and 47 (94%) non-diabetic patients (P = 0.002). Abdominal pain or discomfort during and an hour after the procedure was similar in both groups (P >0.05). The changes in Na, K, Ca, P and creatinine levels after NaP use did not reach statistical significance between the groups (P >0.05). In the diabetic patients, there was a significant correlation between the quality of bowel cleansing and mean age, duration of diabetes mellitus, level of hemoglobin A1c (HbA1c), fasting blood glucose level, and diabetic late complications (P <0.05).

CONCLUSION

These data suggest that NaP is safe and tolerable in diabetic patients, but the quality of bowel cleansing is worse than in non-diabetic patients. These observations support the concept that the quality of bowel cleansing in those with type 2 diabetes is closely related to the duration and regulation of the disease and the presence of late complications.

Does constipation predict the quality of bowel preparation during colonoscopy?

BACKGROUND

Suboptimal bowel preparation has several consequences, including reduced polyp detection rate and increased cost of colorectal cancer screening. The presence of constipation is thought to be a feature associated with poor bowel preparation.

OBJECTIVES

To characterise the relationship between features of constipation and the quality of bowel preparation during colonoscopy.

DESIGN

Patients presenting for an outpatient colonoscopy were asked to complete a questionnaire which included demographics, type of bowel purgative and features of bowel movements (BMs)-derived from the ROME III criteria for diagnosis of chronic constipation.

PATIENTS

101 patients from the community undergoing surveillance colonoscopy completed the study.

INTERVENTIONS

Patients underwent standard bowel preparation, completed a pre-endoscopy survey, followed by routine surveillance colonoscopy.

MAIN OUTCOME MEASUREMENTS

The endoscopist rated the quality of bowel preparation using the previously validated Ottawa scoring scale. Statistical analysis was performed to characterise the relationship between the existence of chronic constipation and quality of bowel preparation.

RESULTS

BM frequency of <1/day, 1/day, 2/day, or 3/day was inversely correlated with average total Ottawa score (range 5.93 to 4.00), p=0.028) as well as recto-sigmoid Ottawa score (range 1.8 to 1.0, p=0.006). Among women, there was a statistically significant (p=0.025) association between those who reported hard stools (Ottawa=6.3) and those who denied hard stools (4.5).

CONCLUSION

Eliciting features of BMs before colonoscopy may predict those at risk for poor bowel preparations and increase cost effectiveness of colonoscopy.

A prospective assessment of renal impairment after preparation for colonoscopy: oral sodium phosphate appears to be safe in well-hydrated subjects with normal renal status

BACKGROUND

The outcome of colonoscopy is highly dependent upon the quality of bowel cleansing prior to the procedure. Oral sodium phosphate solutions (OSPS) or preparations containing polyethylene glycol (PEG) are generally employed. However, the safety of administering OSPS prior to colonoscopy has been questioned because of the potential for renal failure.

AIM

To compare rates of renal failure after OSPS and PEG in a randomized, prospective trial and to assess the quality of colonoscopy after these two bowel preparations.

METHODS

Subjects with eGFR >or= 60 ml/min/1.73 m(2) and expressed willingness to adhere to hydration recommendations were randomized to OSPS or PEG solutions. Renal function was assessed 1 week prior to, immediately prior to, and 1 week after colonoscopy.

RESULTS

No subject had acute kidney failure after OSPS or PEG. OSPS was associated with significant increases in the serum phosphate and sodium levels and significant decreases in the calcium and potassium levels. These values returned to normal limits in all subjects by 1 week after colonoscopy. The quality of colonic cleansing was superior after OSPS than after PEG (Ottawa score 2.5 +/- 2.2 vs. 3.5 +/- 2.3, respectively, P < 0.05). The detection of one or more adenomatous polyps was higher after OSPS than after PEG.

CONCLUSIONS

Renal failure was not detected after the use of OSPS for colonoscopy preparation in subjects with recently documented normal renal function who were able to consume the required amounts of water after each dose. However, based on the number of subjects studied, the theoretical risk of this complication is still between 0 and 6.3%. Thus, it is appreciated that only a very large prospective trial would have yielded a more accurate estimate of the likelihood of renal compromise after OSPS. Despite this caveat, OSPS has advantages over PEG in terms of the adequacy of colonic visualization and the number of polyps detected.

The effect of autonomous neuropathy on bowel preparation in type 2 diabetes mellitus

INTRODUCTION

The need for colonoscopy is common among diabetics. In this study, we aimed to evaluate the effect of autonomous neuropathy on bowel preparation in type 2 diabetes mellitus (DM) patients.

MATERIALS AND METHODS

The study population consisted of 45 patients with DM and 48 non-diabetic, age- and sex-matched subjects. All colonoscopies were performed 5 h after the last dose of sodium phosphate. Colonoscopists rated the bowel preparation quality during the procedure using the Aronchick scale. All patients underwent a detailed cardiologic examination and 24-h Holter rhythm monitoring. Orthostatic hypotension and impairment in heart rate variability were accepted as indicators of autonomous neuropathy.

RESULTS

Gender, age, blood pressure, and heart rates did not differ significantly between groups (p > 0.05). Autonomous neuropathy was detected in 14 (31.1%) patients in the DM group and in two (4.2%) in the control group (p < 0.05). Optimal bowel cleansing was achieved in 93.8% of controls and 73.3% of diabetics; bowel cleansing was suboptimal in 26.7% of diabetics and 6.2% of controls (p < 0.05). Optimal bowel cleansing was achieved in six of 14 (42.8%) diabetic patients with autonomous neuropathy; however, optimal bowel cleansing was achieved in 27 of 31 (87.1%) diabetic patients without autonomous neuropathy (p < 0.05). Although optimal bowel cleansing was more prevalent among control patients than in diabetic patients without autonomous neuropathy, the difference was not significant (87.1% vs 93.8%; p > 0.05).

CONCLUSION

These data suggest that optimal bowel cleansing is poorer in diabetics with autonomous neuropathy than in those without autonomous neuropathy and controls.

Randomized study comparing two regimens of oral sodium phosphates solution versus low-dose polyethylene glycol and bisacodyl

PURPOSE

Low-volume bowel preparation regimens for colonoscopy are reported to improve patient acceptance and compliance. We sought to compare the bowel cleansing efficacy, tolerability, and acceptability of three low-volume regimens: an oral sodium phosphates solution 45/45 ml (NaP-45/45), a reduced-dose oral sodium phosphates solution 45/30 ml (NaP-45/30), and polyethylene glycol plus bisacodyl (PEG-2L).

RESULTS

A total of 121 patients were evaluated (mean age 55.2 +/- 8.9 years). Bowel cleansings rated as excellent and good were significantly different among the groups: NaP-45/45 = 98%, NaP-45/30 = 88%, and PEG-2L = 76% (P < 0.04). Side effects were not significantly different except for greater thirst in the NaP-45/45 group (P = 0.001) and increased vomiting in females using PEG-2L (two-tailed interaction, P < 0.10). Willingness to retake the preparation was higher among the sodium phosphates regimens (88, 95, and 73%, respectively; P = 0.019).

CONCLUSIONS

Better cleansing and willingness to retake the regimen was achieved with the oral sodium phosphates solutions than with polyethylene glycol plus bisacodyl.

Gastroenterologists' patient instructions for oral sodium phosphate solution for colonoscopy preparation: a survey among gastroenterologists in the state of Indiana

BACKGROUND

Oral sodium phosphate solution (OSPS) has been associated with acute renal failure when used as a bowel preparation for colonoscopy.

AIM

To determine whether gastroenterologists in Indiana follow recent recommendations for safe and effective use of colonoscopy.

METHODS

A survey of gastroenterologists in Indiana performed in mid-2006. Written instruction to patients were obtained and reviewed.

RESULTS

We received responses from 97.5% of Indiana gastroenterologists, of whom 80% reported using OSPS. All using OSPS forwarded their written instructions. None exceeded the recommended two 45 mL doses in their written instructions. Although separation of the two 45 mL doses by at least 6 to 12 hours is recommended, 35% of physicians prescribed the 2 doses at intervals less than 6 hours. Only 9.7% gave specific instructions for volumes of fluid to be taken before the first dose. Fluid prescriptions during the preparation were often suboptimal according to current recommendations. Less than 25% of physicians followed the recommendation to use carbohydrate-electrolyte solutions for hydration.

CONCLUSIONS

Gastroenterologists in Indiana in mid-2006 uniformly followed recommendations for maximum doses of OSPS, but recommended intervals for the doses and gave hydration instructions that often did not follow current recommendations.

Comparação entre as soluções orais de manitol a 10% e bifosfato de sódio no preparo mecânico do cólon

OBJETIVO: Comparar o uso das soluções orais de manitol a 10% e de bifosfato de sódio no preparo mecânico do cólon quanto a qualidade da limpeza, a tolerabilidade e as alterações hidroeletrolíticas e da osmolaridade plasmática. MÉTODO: Foram analisados 60 pacientes de modo randomizado, duplo-cego e prospectivo, com indicação de colonoscopia. A qualidade da limpeza intestinal foi analisada pelo examinador através da classificação de Beck. A tolerabilidade à ingestão baseou-se na pesquisa do gosto, presença ou não de desconforto, aparecimento de efeitos adversos e a quantidade da solução ingerida. Foram dosados o sódio, potássio, cálcio, magnésio, fósforo, uréia, creatinina, glicose, hematócrito, hemoglobina e calculado a osmolaridade plasmática, antes e após a ingestão da solução oral de preparo inestinal. RESULTADOS: Ambas as soluções atingiram qualidade de preparo classificado como bom ou superior em mais de 80% dos pacientes. O uso do bifosfato de sódio determinou menor desconforto e melhor tolerância, apesar de não ter sido superior ao manitol quanto à análise do gosto e presença de efeitos adversos. O bifosfato induziu ao aumento e o manitol a uma redução da osmolaridade, reflexo do que ocorreu com o sódio plasmático nos dois grupos respectivamente. O bifosfato ainda determinou alteração significativa dos níveis séricos de fósforo, cálcio, magnésio e potássio, sem repercussões clínicas. CONCLUSÃO: Ambos os tipos de preparo intestinal determinaram qualidade de limpeza adequada. O bifosfato de sódio, apesar de melhor tolerado, determina maior quantidade de alterações hidroeletrolíticas.

Oral colorectal cleansing preparations in adults

Bowel preparation has been a much-debated issue for both colonoscopy and for colorectal surgery. While bowel preparation for colonoscopy is clearly mandatory for optimal intraluminal visualization, bowel preparation for surgery has recently been challenged. This review evaluates oral bowel preparation, based on evidence in the literature, in order to provide a practical guide for physicians and practitioners about oral bowel cleansing preparations in current use for both colonoscopy and for colorectal surgery.A MEDLINE search, limited to publications in English language, was done through Ovid including articles published from 1966 to 2007 about bowel preparation using terms 'pre-operative care' and 'colonoscopy' or 'surgical procedure' associated with 'polyethylene glycol' and 'sodium phosphate'. The references lists from the identified articles were also included in the review. No bowel preparation method meets the ideal criteria for bowel cleansing prior to colonoscopy. However, polyethylene glycol-electrolyte lavage solution (PEG-ELS) and sodium phosphate are the most commonly used bowel preparations before colonoscopy and colon surgery. Both preparations are safely used and effective; however, some precautions should be considered, particularly with sodium phosphate. In addition, the efficacy of low-volume PEG-ELS can be improved by the addition of preparation adjuncts. Timing and dose are important considerations regardless of the method used. Mechanical bowel preparation for surgery has been questioned, and shown to have no extra benefits and possibly the association with increased morbidity. Regardless of the evidence, there are many randomized controlled trials showing the lack of benefit of mechanical bowel preparation.

Colon cleansing with oral sodium phosphate in adolescents: dose, efficacy, acceptability, and safety

BACKGROUND AND AIMS

Standardized bowel preparation in children and adolescents has not been established. Our aim was to compare two bowel preparation regimens and determine which was more effective, acceptable, and safer for children undergoing colonoscopy.

METHODS

We compared the efficacy and acceptability of a 1-day regimen with oral sodium phosphate solution (NaP solution) (1 mL/kg/day, maximum 90 mL in two divided doses; regimen A) to our standard 3-day regimen magnesium citrate (4 mL/kg/day x 3 days, maximum 237 mL, followed by an enema the morning of colonoscopy; regimen B). After informed consent was obtained, 48 children were randomized (N = 25, 23, respectively). Weight, electrolytes, calcium, phosphorus, and magnesium were measured at screening and the day of the colonoscopy. Questionnaires were given to assess acceptability and adverse events. Endoscopists rated the quality of bowel preparation on a 4-level scale from excellent to poor.

RESULTS

Median age and weight at screening were 14 yr, 53 kg, and 15 yr, 51 kg in regimen A and B, respectively. No statistical significance was observed in electrolytes, phosphorus, or adverse events apart from higher nausea intensity in regimen A (P= 0.012). Bowel cleansing was similar between groups (71% excellent or good). Subjects were more willing to repeat regimen A than B (77%vs 32%, respectively, P < 0.006). All 10 subjects who received regimen A and had prior colonoscopies using regimen B, preferred regimen A.

CONCLUSIONS

In a selected group of otherwise healthy children and adolescents over 10.5 yr and above 34 kg, 1-day oral NaP solution was more acceptable than 3-day magnesium citrate with an enema, and both regimens were found to be safe and efficacious.

Randomized trial of low-volume PEG solution versus standard PEG + electrolytes for bowel cleansing before colonoscopy

OBJECTIVES

Polyethylene glycol (PEG)-based gut lavage solutions are safe and effective, but require consumption of large volumes of fluid. We compared a new 2 L solution of PEG plus ascorbic acid (PEG + Asc) with standard 4 L PEG with electrolytes (PEG + E) for bowel cleansing before colonoscopy to determine efficacy, safety, and patient acceptability.

METHODS

Consenting adult inpatients scheduled to undergo colonoscopy were randomized to receive either 2 L PEG + Asc or 4 L PEG + E. Preparations were taken as split doses the evening before colonoscopy and the following morning. The PEG + Asc group took 1 L at each administration (i.e., total dose of 2 L). The PEG + E group took 2 L at each administration (i.e., total dose of 4 L). Bowel cleansing success was assessed via videotapes by independent, blinded raters. Statistical noninferiority was predefined as a difference of <15% in the lower limit of the 97.5% confidence interval for treatment difference. Patient views on the preparations were elicited. Adverse events were noted.

RESULTS

Successful gut cleansing was achieved in 136 of 153 (88.9%) cases of the PEG + Asc group and 147 of 155 (94.8%) cases of the 4 L PEG + E group (mean difference -5.9 [-12.0-infinity]). The difference fell within the predefined limit for noninferiority. Clinical and laboratory parameters showed no difference in safety profile. Patient ratings of acceptability and taste were better for the PEG + Asc group than for the PEG + E group (P < 0.025).

CONCLUSIONS

The combination of ascorbic acid and PEG-based bowel preparation reduces the volume patients have to drink without compromising efficacy or safety. The low-volume PEG + Asc preparation was more acceptable to patients, and should, therefore, improve effectiveness in routine practice.

Review article: Bowel preparation for colonoscopy--the importance of adequate hydration

BACKGROUND

Patient compliance with screening recommendations for colorectal cancer remains low, despite a 90% survival rate achieved with early detection. Bowel preparation is a major deterrent for patients undergoing screening colonoscopy. More than half of patients taking polyethylene glycol electrolyte lavage solution and sodium phosphate preparations experience adverse events, such as nausea and abdominal pain. Many adverse events may be associated with dehydration, including rare reports of renal toxicity in patients taking sodium phosphate products. Addressing dehydration-related safety issues through patient screening and education may improve acceptance of bowel preparations, promote compliance and increase the likelihood of a successful procedure.

AIM

To evidence safety issues associated with bowel preparation are generally related to inadequate hydration.

RESULTS

Dehydration-related complications may be avoided through proper patient screening, for example, renal function and comorbid conditions should be considered when choosing an appropriate bowel preparation. In addition, patient education regarding the importance of maintaining adequate hydration before, during and after bowel preparation may promote compliance with fluid volume recommendations and reduce the risk of dehydration-related adverse events.

CONCLUSIONS

Proper patient screening and rigorous attention by patients and healthcare providers to hydration during bowel preparation may provide a safer, more effective screening colonoscopy.

A review of current issues underlying colon cleansing before colonoscopy

The present review examines four current issues related to the efficacy, patient tolerance and safety of the following bowel cleansing agents: oral sodium phosphate (NaP), polyethylene glycol (PEG) and magnesium citrate (Pico-Salax, Ferring Pharmaceuticals Inc, Canada), an agent recently made available in Canada. MedLine and PubMed databases were systematically searched to identify studies related to the efficacy of altered PEG solutions combined with adjunct treatments; the efficacy, tolerability and safety of Pico-Salax; the association between nephrocalcinosis, and chronic renal failure and oral NaP use; and the role of diet. Although lower volume PEG solutions combined with adjuvant agents were generally associated with better patient tolerance, their efficacy was varied and interpretation of this end point is complicated by study design issues. There are very few reported studies of Pico-Salax, and as a result, there are insufficient data to draw conclusions about the efficacy of this agent. The available data suggest that Pico-Salax may be better tolerated by patients, than oral NaP and PEG solutions. There is a paucity of hemodynamic monitoring data pre- and postadministration, but the available data suggests that this small-volume osmotic agent could cause subclinical contraction of the intravascular space. Recent case reports suggest an association between nephrocalcinosis and oral NaP ingestion, but to date, these reports have been confined to a single centre. Preliminary studies suggest that this is not a widespread problem, but more studies are needed. There are only a few studies examining diet and patient tolerability, but they do suggest that diet may be liberalized with some cleansing regimens to enhance tolerability without decreasing efficacy. The present review highlights current controversies and advances in colon cleansing before colonoscopy, and also identifies areas for further study.

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.

Commonly used preparations for colonoscopy: efficacy, tolerability, and safety--a Canadian Association of Gastroenterology position paper

INTRODUCTION

The increased demand for colonoscopy, coupled with the introduction of new bowel cleansing preparations and recent caution advisories in Canada, has prompted a review of bowel preparations by the Canadian Association of Gastroenterology.

METHODS

The present review was conducted by the Clinical Affairs group of committees including the endoscopy, hepatobiliary/transplant, liaison, pediatrics, practice affairs and regional representation committees, along with the assistance of Canadian experts in the field. An effort was made to systematically assess randomized prospective trials evaluating commonly used bowel cleansing preparations in Canada.

RESULTS

Polyethylene glycol (PEG)-; sodium phosphate (NaP)-; magnesium citrate (Mg-citrate)-; and sodium picosulphate, citric acid and magnesium oxide (PSMC)-containing preparations were reviewed. Regimens of PEG 2 L with bisacodyl (10 mg to 20 mg) or Mg-citrate (296 mL) are as effective as standard PEG 4 L regimens, but are better tolerated. NaP preparations appear more effective and better tolerated than standard PEG solutions. PSMC has good efficacy and tolerability but head-to-head trials with NaP solutions remain few, and conclusions equivocal. Adequate hydration during preparation and up to the time of colonoscopy is critical in minimizing side effects and improving bowel cleansing in patients receiving NaP and PSMC preparations. All preparations may cause adverse events, including rare, serious outcomes. NaP should not be used in patients with cardiac or renal dysfunction (PEG solution is preferable in these patients), bowel obstruction or ascites, and caution should be exercised when used in patients with pre-existing electrolyte disturbances, those taking medications that may affect electrolyte levels and elderly or debilitated patients. Health Canada's recommended NaP dosing for most patients is two 45 mL doses 24 h apart. However, both safety and efficacy data on this dosing schedule are lacking. Many members of the Canadian Association of Gastroenterology expert panel administer both doses within 24 h, as studied in clinical trials, after careful one-on-one discussion of risks and benefits in carefully selected patients. Safety data on PSMC and combination preparations in North America are limited and clinicians are encouraged to keep abreast of developments in this area.

CONCLUSIONS

All four preparations reviewed provided effective bowel cleansing for colonoscopy in the majority of patients, with varying tolerability. Adequate hydration is essential in patients receiving the preparations.

A randomized prospective trial comparing different regimens of oral sodium phosphate and polyethylene glycol-based lavage solution in the preparation of patients for colonoscopy

BACKGROUND

Regulatory agencies have warned clinicians regarding the risk of electrolyte abnormalities if more than two 45-mL bottles of oral sodium phosphate (NaP) solution are administered within a 24-hour period.

OBJECTIVE

To compare the efficacy, safety, and tolerability of different regimens of oral NaP and polyethylene glycol (PEG).

DESIGN

Randomized controlled trial.

SETTING

Teaching hospital outpatient endoscopy clinic.

PATIENTS

Two hundred outpatients without comorbidities who underwent routine colonoscopy.

INTERVENTIONS

Two bottles of NaP, 6, 12, or 24 hours apart; or 4 L PEG.

MAIN OUTCOME MEASUREMENTS

Bowel preparation quality, patient tolerability, and electrolyte changes.

RESULTS

The 12- and 24-hour NaP achieved better cleansing than the 6-hour NaP or PEG. Only 8.5% and 8.3% of patients in the 24- and 12-hour NaP had poor preparations, respectively, compared with 15.6% and 23.4% in the 6-hour NaP and PEG, respectively. The poorer preparation scores with PEG were partly because of a greater amount of colonic fluid. There were no relevant electrolyte changes with PEG, whereas hypokalemia, hypocalcemia, or hyperphosphatemia developed in 5% to 57% of patients on NaP. All regimens were poorly tolerated by patients.

LIMITATIONS

The study was likely underpowered to detect small group differences in electrolytes.

CONCLUSIONS

A 24- or 12-hour NaP bowel preparation strategy was more effective than NaP 6 hours apart or PEG. PEG use is associated with more residual colonic fluid but represents an alternative to NaP in some clinical situations.

Combined low volume polyethylene glycol solution plus stimulant laxatives versus standard volume polyethylene glycol solution: a prospective, randomized study of colon cleansing before colonoscopy

INTRODUCTION

The effectiveness of polyethylene glycol solutions (PEG) for colon cleansing is often limited by the inability of patients to drink adequate portions of the 4 L solution. The aim of the present study was to determine whether a reduced volume of PEG combined with stimulant laxatives would be better tolerated and as or more effective than the standard dose.

METHODS

Patients undergoing outpatient colonoscopy were randomly assigned to receive either low-volume PEG plus sennosides (120 mg oral sennosides syrup followed by 2 L PEG) or the standard volume preparation (4 L PEG). The subjects rated the tolerability of the preparations and their symptoms. Colonoscopists were blind to the colonic cleansing preparation and graded the cleansing efficacy using a validated tool (the Ottawa scale).

RESULTS

The low-volume PEG plus sennosides preparation was significantly better tolerated than the standard large volume PEG (P<0.001) but was less efficacious (P=0.03). Thirty-eight per cent of patients in the large volume PEG group were unable to finish the preparation, compared with only 6% in the reduced volume group. There were no adverse events reported.

CONCLUSIONS

Although the low-volume PEG plus sennosides preparation was better tolerated, it was not as effective as standard large-volume PEG. However, in view of the significant difference in tolerance, further research investigating possible improvements in the reduced-volume regimen seems warranted.

Which is the optimal bowel preparation for colonoscopy - a meta-analysis

OBJECTIVE

To assess which bowel preparation agent is most effective.

METHODS

A search of randomized trials between January 1990 and July 2005 was obtained, using MEDLINE and PubMed databases, and the Cochrane Central Register of Controlled Trials. Meta-analysis was performed using the Forest plot review.

RESULTS

Sodium phosphate (NaP) was more effective in bowel cleansing than polyethylene glycol (PEG) - odds ratio 0.75 (95%CI: 0.65-0.88; P = 0.0004); and sodium picosulphate (SPS) - odds ratio 0.52 (95%CI: 0.34-0.81; P = 0.004). PEG and SPS were comparable in bowel cleansing ability, odds ratio 1.69 (95%CI: 0.92-3.13; P = 0.09). NaP was more easily completed by patients compared to PEG, odds ratio 0.16 (95%CI: 0.09-0.29; P < 0.00001). More patients were able to complete SPS than PEG, but this was not statistically significant - odds ratio 0.56 (95%CI: 0.28-1.13; P = 0.11). NaP and PEG were comparable in terms of adverse events, odds ratio 0.98 (95%CI: 0.82-1.17; P = 0.81), although NaP resulted in more asymptomatic hypokalaemia and hyperphosphataemia. NaP and SPS appeared to have similar incidence of adverse events. PEG resulted in more adverse events than SPS, odds ratio 3.82 (95%CI: 1.60-9.15; P = 0.003).

CONCLUSIONS

NaP was more effective in bowel cleansing than PEG or SPS and was comparable in terms of adverse events. Patients have more difficulty completing PEG than NaP and SPS. Biochemical changes associated with a small-volume preparation like NaP, albeit largely asymptomatic, mandate caution in patients with cardiovascular or renal impairment.

A prospective randomized blinded comparison of sodium phosphate and polyethylene glycol-electrolyte solution for safe bowel cleansing

BACKGROUND

Polyethylene glycol-electrolyte solution (PEG-ELS) is routinely prescribed for bowel cleansing. Sodium phosphate (NaP) may be an effective but potentially hazardous alternative.

AIM

To investigate the safety of prescription of either agent, without being informed of the patient's medical history.

METHODS

One hundred consecutive patients were randomly allocated to PEG-ELS or NaP. Prior to and after the bowel cleansing, blood was sampled for renal function and electrolytes. Patients answered questionnaires about complaints and ease of intake, and endoscopists rated the quality of bowel preparation.

RESULTS

Eleven patients were identified with a theoretical contraindication for NaP, of whom nine should have been discovered by taking a detailed clinical history. Actually, six of them received NaP with a doubling of serum phosphate levels or hypokalaemia in four. In subjects without a contraindication to the use of NaP, hyperphosphataemia developed in 39% and hypocalcaemia in 5%. Patients tolerated NaP better and completed the preparation more often. Endoscopists rated the quality of bowel preparation equivalent, except for a better cleansed ascending colon with PEG-ELS.

CONCLUSIONS

The 11% potentially hazardous allocation to NaP and the 39% incidence of hyperphosphataemia with NaP do not justify an 'over-the-counter' prescription. Taking a detailed history and, when in doubt, using PEG-ELS will safeguard against inappropriate administration of NaP.

A randomized single-blind trial of split-dose PEG-electrolyte solution without dietary restriction compared with whole dose PEG-electrolyte solution with dietary restriction for colonoscopy preparation

BACKGROUND

Colonoscopy preparation regimens are poorly tolerated, requiring the use of a large volume of an unpalatable solution and diet restriction for adequate cleansing. The aim of this study was to compare the efficacy of two regimens of bowel preparation before colonoscopy: a whole dose of polyethylene glycol electrolyte solution (PEG-E), with diet restriction vs. a split dose with no diet restriction.

METHODS

A total of 141 patients (ages 20-84 years, 81 men) were randomly assigned to receive either 4 L PEG-E, along with a liquid diet the day before colonoscopy (Group A) or 2 L PEG-E with a regular diet the day before colonoscopy followed by another 2 L PEG-E on the day of the procedure (Group B). The quality of the preparation was graded by the endoscopist (poor to excellent), who was blinded to the type of preparation. Tolerability of the assigned preparation and adverse effects were recorded by an independent investigator by using a questionnaire administered before colonoscopy. Intra- and interobserver variability was studied by using randomly chosen videotapes of colonoscopies performed as part of the study.

RESULTS

There were 73 patients in Group A and 68 patients in Group B. The quality of the preparation was significantly better in Group B ( p = 0.011). The tolerability of the preparation regimen was not different overall between study groups in terms of side effects (except for bloating, which was more frequent in Group B, p = 0.039) or willingness to repeat the preparation. There was a nonsignificant trend toward improved adherence to the assigned preparation in favor of Group B ( p = 0.062). Inter- and intraobserver variability analysis showed good to excellent correlation among endoscopists.

CONCLUSIONS

Colonic preparation with split-dose PEG-E and no dietary restriction provides better quality colon cleansing than whole-dose preparation, with no significant impact on patient tolerability and side effects.

Hyponatremia and seizures after bowel preparation: report of three cases

Oral sodium phosphate and sodium picosulfates/magnesium citrate are commonly used to evacuate the colon and rectum before colonoscopy or colorectal surgery. These substances, however, are known to cause electrolyte abnormalities. Seizures caused by electrolyte abnormalities associated with bowel preparation have only rarely been reported. We report the cases of three patients with no prior history of seizures, who had their first seizure associated with hyponatremia following ingestion of sodium phosphate or sodium picosulfates/magnesium citrate combination. Care must be taken with patients with a low seizure threshold and those with possible chronic sodium depletion, such as patients on thiazide diuretics, who are undertaking bowel preparation with oral sodium phosphate or sodium picosulfates/magnesium citrate combination.