Systematic review and meta-analysis: Efficacy of patented probiotic, VSL#3, in irritable bowel syndrome.

BACKGROUND: VSL#3 is a patented probiotic for which several clinical trials suggest benefits on motor function, bloating, and symptoms of irritable bowel syndrome (IBS). OBJECTIVES: To quantify effects of VSL#3 on abdominal pain, stool consistency, overall response, abdominal bloating, and quality of life (QOL) in IBS through meta-analysis. METHODS: MEDLINE (OvidSP and PubMed), EMBASE, Web of Science, and Scopus were searched up to May 2017. Using a fixed effects model, we pooled data from intention-to-treat analyses of randomized trials (RCTs) comparing VSL#3 to placebo in IBS. Data were reported as relative risk (RR), overall mean difference (MD), or standardized MD (SMD) with 95% confidence intervals (CI). Quality of evidence was rated using the GRADE approach. KEY RESULTS: Among 236 citations, 5 RCTs (243 patients) were included. No significant differences were observed for abdominal pain (SMD = -0.03; 95% CI -0.29 to 0.22), bloating (SMD = -0.15; 95% CI -0.40 to 0.11), proportion of bowel movements with normal consistency (overall MD = 0; 95% CI -0.09 to 0.08), or IBS-QOL (SMD = 0.08; 95% CI -0.22 to 0.39). VSL#3 was associated with a nearly statistically significant increase in overall response (RR = 1.39; 95% CI 0.99-1.98). CONCLUSIONS & INFERENCES: In this systematic review and meta-analysis, there was a trend toward improvement in overall response with VSL#3, but no clear evidence effectiveness for IBS. However, the number and sample sizes of the trials are small and the overall quality of evidence for 3 of the 5 outcomes was low. Larger trials evaluating validated endpoints in well-defined IBS patients are warranted.

A quantitative assessment of the risks and cost savings of forgoing histologic examination of diminutive polyps.

BACKGROUND AND AIMS: Endoscopic prediction of polyp histology is rapidly improving to the point where it may not be necessary to submit all polyps for formal histologic assessment. This study aimed to quantify the expected costs and outcomes of removing diminutive polyps without subsequent pathologic assessment. METHODS: Cross-sectional analysis of a colonoscopy database for polyp histology; decision models that quantify effects on guideline-recommended surveillance and subsequent costs and consequences. The database was composed of consecutive colonoscopies from 1999 to 2004 at a single-institution tertiary care center. Patients were those found to have at least one diminutive polyp removed during colonoscopy, irrespective of indication. The main outcome measurements include up-front cost savings resulting from forgoing pathologic assessment; frequency and cost of incorrect surveillance intervals based on errors in histologic assessment; number needed to harm (NNH) for perforation and/or interval cancer. RESULTS: Incorrect surveillance intervals were recommended in 1.9% of cases when tissue was submitted for pathologic assessment and 11.8% of cases when it was not. Based on the annual volume of colonoscopy in the US, the annual up-front cost savings of forgoing the pathologic assessment would exceed a billion dollars. An upper estimate on the downstream costs and consequences of forgoing pathology suggests that less than 10% of the up-front savings would be offset and the NNH exceeds 11000. CONCLUSION: Endoscopic diagnosis of polyp histology during colonoscopy and forgoing pathologic examination would result in substantial up-front cost savings. Downstream consequences of the resulting incorrect surveillance intervals appear to be negligible.

Meta-analysis: randomized controlled trials of 4-L polyethylene glycol and sodium phosphate solution as bowel preparation for colonoscopy.

BACKGROUND: Randomized controlled trials (RCTs) comparing polyethylene glycol (PEG) with sodium phosphate (NaP) are inconsistent. AIM: To compare the efficacy of and tolerance to PEG vs. NaP for bowel preparation. METHODS: We used MEDLINE and EMBASE to identify English-language RCTs published between 1990 and 2008 comparing 4-L PEG with two 45 mL doses of NaP in adults undergoing elective colonoscopy. We calculated the pooled odds ratios (ORs) for preparation quality and proportion of subjects completing the preparation. RESULTS: From 18 trials (n = 2792), subjects receiving NaP were more likely to have an excellent or good quality preparation than those receiving PEG (82% vs. 77%; OR = 1.43; 95% CI, 1.01-2.00). Among a subgroup of 10 trials in which prep quality was reported in greater detail, there were no differences in the proportions of excellent, good, fair or poor preparation quality. Among nine trials that assessed preparation completion rates, patients receiving NaP were more likely to complete the preparation than patients receiving 4-L PEG (3.9% vs. 9.8% respectively did not complete the preparation; OR = 0.40; CI, 0.17-0.88). CONCLUSION: Among 18 head-to-head RCTs of NaP vs. 4-L PEG, NaP was more likely to be completed and to result in an excellent or good quality preparation.

Surveillance approaches among colorectal cancer survivors after curative-intent.

Intensive surveillance among colorectal cancer patients receiving curative-intent, particularly during the first 2 to 3 years of follow-up, has a beneficial impact upon all-cause survival at five years. Intensive surveillance appears to be associated with the early detection of recurrences, and more often accompanied by a clinical presentation enabling surgical resection. The optimal combination and frequency of surveillance tests is unknown. Imaging of the chest and abdomen have increasingly been recommended by professional organizations, in addition to CEA levels, in order to detect resectable recurrences. Metachronous cancers are relatively uncommon, nonetheless, surveillance colonoscopy is typically recommended. Cau-tion is warranted in further advancing the intensity of surveillance, as increasingly aggressive surveillance programs risk increased detection of pseudodisease. Different types of information will enhance our understanding of the impact of follow-up programs, including data regarding quality of life, cost, and patient preferences.

Evaluation of the Winthrop-University Hospital criteria to identify Legionella pneumonia.

STUDY OBJECTIVE: To measure the ability of a set of clinical parameters, the Winthrop-University Hospital (WUH) criteria, to identify Legionella pneumonia while discriminating against bacteremic pneumococcal pneumonia at the time of hospitalization for community-acquired pneumonia (CAP). DESIGN: Retrospective case-control study. SETTING: An urban county hospital and a tertiary-care Veterans Affairs hospital. PATIENTS: Thirty-seven patients with Legionella pneumonia (diagnosed by a positive result of a urinary Legionella antigen test) and 31 patients with bacteremic pneumococcal pneumonia. A subgroup of patients with all required laboratory criteria were studied further. RESULTS: The WUH criteria correctly identified 29 of 37 patients with Legionella pneumonia (sensitivity, 78%; 95% confidence interval [CI], 61 to 90%), while successfully excluding legionellosis in 20 of 31 patients with bacteremic pneumococcal pneumonia (specificity, 65%; 95% CI, 45 to 80%). The positive and negative predictive values, adjusted for a relative prevalence of 1:3 between Legionella and Streptococcus pneumoniae bacteremia, were 42% (95% CI, 25 to 61%) and 90% (95% CI, 74 to 97%), respectively. In the subgroup analysis, the WUH criteria were successful in identifying 20 of 23 patients with Legionella pneumonia (sensitivity, 87%; 95% CI, 65 to 97%), while excluding legionellosis in 9 of 18 patients with bacteremic pneumococcal pneumonia (specificity, 50%; 95% CI, 27 to 73%). The adjusted positive and negative predictive values for a 1:3 relative prevalence were 37% (95% CI, 20 to 59%) and 92% (95% CI, 62 to 98%), respectively. The predictive values were changed in the directions expected for an increased relative prevalence of 1:1. The areas under the receiver operating characteristic curves were 0.72 +/- 0.06 for the entire study group and 0.68 +/- 0.09 for the subgroup. CONCLUSIONS: Although the WUH criteria discriminated fairly well between cases (mean +/- SE) and control subjects, the sensitivity is not high enough to exclude legionellosis confidently. These results suggest that empiric therapy for Legionella pneumonia should be included in the initial antibiotic regimen for hospitalized patients with CAP.

A meta-analysis of endoscopic variceal ligation for primary prophylaxis of esophageal variceal bleeding.

Despite publication of several randomized trials of prophylactic variceal ligation, the effect on bleeding-related outcomes is unclear. We performed a meta-analysis of the trials, as identified by electronic database searching and cross-referencing. Both investigators independently applied inclusion and exclusion criteria, and abstracted data from each trial. Standard meta-analytic techniques were used to compute relative risks and the number needed to treat (NNT) for first variceal bleed, bleed-related mortality, and all-cause mortality. Among 601 patients in 5 homogeneous trials comparing prophylactic ligation with untreated controls, relative risks of first variceal bleed, bleed-related mortality, and all-cause mortality were 0.36 (0.26-0.50), 0.20 (0.11-0.39), and 0.55 (0.43-0.71), with respective NNTs of 4.1, 6.7, and 5.3. Among 283 subjects from 4 trials comparing ligation with beta-blocker therapy, the relative risk of first variceal bleed was 0.48 (0.24-0.96), with NNT of 13; however, there was no effect on either bleed-related mortality (relative risk [RR], 0.61; confidence interval [CI], 0.20-1.88) or all-cause mortality (RR, 0.95; CI, 0.56-1.62). In conclusion, compared with untreated controls, prophylactic ligation reduces the risks of variceal bleeding and mortality. Compared with beta-blockers, ligation reduces the risk for first variceal bleed but has no effect on mortality. Prophylactic ligation should be considered for patients with large esophageal varices who cannot tolerate beta-blockers. Subsequent research should further compare ligation and beta-blockers to determine the effect on mortality, and measure ligation's cost-effectiveness.

A cost-minimization analysis of alternative treatment strategies for achalasia.

OBJECTIVE: The aim of this study is to compare the costs per cure of alternative strategies for the treatment of achalasia. METHODS: A cost-minimization model compared three strategies for otherwise healthy adults of any age with achalasia: 1) laparoscopic Heller myotomy with fundoplication (LHM); 2) pneumatic dilation (PD), with LHM reserved for treatment failures; 3) botulinum toxin (Botox) injection of the lower esophageal sphincter, with PD reserved for treatment failures. Probabilities of short- and long-term efficacy, treatment failure, symptomatic recurrence rates, and complications were derived from the published literature. Only direct costs were considered during the 5-yr time horizon. RESULTS: Respective reference case costs per cure of PD, Botox, and LHM strategies were $3,111, $3,723, and $10,792. Despite short- and long-term efficacy of 96% and 94%, respectively, the LHM strategy was most costly. Initial PD remained less costly than initial Botox, provided that rates of PD efficacy and perforation were > or = 70% and < 9.5%, respectively, and cost of a Botox session was > or = $450. The results were not sensitive to the probabilities of short- and long-term response to Botox, recurrence after PD, LHM efficacy, and post-LHM gastroesophageal reflux disease, nor to the costs of LHM and PD. CONCLUSIONS: For otherwise healthy patients with achalasia, initial PD is the least costly strategy provided that the PD perforation rate remains < 10%. Initial Botox is less costly only when nonendoscopic-related costs decrease by 25%. Initial LHM is the most costly strategy under all clinically plausible scenarios. Subsequent analyses should include a longer time horizon and an assessment of patient ference for each strategy.

Need for validation of clinical decision aids: use of the AST/ALT ratio in predicting cirrhosis in chronic hepatitis C.

OBJECTIVE: A value of > or = 1 for the ratio of aspartate amino-transferase to alanine aminotransferase (the AST/ALT ratio or AAR) has been shown to have a positive predictive value of 100% for the diagnosis of cirrhosis in patients with chronic hepatitis C. If validated on separate cohorts, an AAR > or = 1 might obviate the need for liver biopsy in some patients with hepatitis C. METHODS: We attempted to validate the AAR by abstracting demographic and clinical data from a database of consecutive patients with hepatitis C who had a liver biopsy between 1993 and 1998. We used definitions, methods of data collection, and analyses comparable to those of the published study. A hepatopathologist blindly reviewed 49 liver biopsies for histological grade and stage. RESULTS: The current cohort of 177 patients and the previous cohort of 139 patients were comparable in mean age (42.3 vs 43.8 yr), percentage of men (63 vs 67), percentage with an AAR > or =1 (20 vs 17), and Child-Pugh distribution, but differed in substantial use of ethanol (11% vs 3.6%; p = 0.01) and in the prevalence of cirrhosis (23% vs 34%, p = 0.06). Respective sensitivities of the AAR were 56% and 53%. An AAR > or =1 had a positive predictive value of 64% (95% confidence interval 48-78%) for the current cohort. Thirteen of 36 patients (36%) with an AAR > or =1 were incorrectly identified as having cirrhosis. Of these 13 patients, 6 had a normal AST and ALT, 5 had a minimally elevated AST or ALT, and 1 had advanced fibrosis without cirrhosis. CONCLUSIONS: These results suggest that an AAR > or =1 may not be as useful for predicting cirrhosis in chronic hepatitis C as previously thought, and emphasizes the need for validation of clinical decision aids on independent patient cohorts.

Risk of advanced proximal neoplasms in asymptomatic adults according to the distal colorectal findings.

BACKGROUND AND METHODS: The clinical significance of a distal colorectal polyp is uncertain. We determined the risk of advanced proximal neoplasia, defined as a polyp with villous features, a polyp with high-grade dysplasia, or cancer, among persons with distal hyperplastic or neoplastic polyps as compared with the risk among persons with no distal polyps. We analyzed data from 1994 consecutive asymptomatic adults (age, 50 years or older) who underwent colonoscopic screening for the first time between September 1995 and December 1998 as part of a program sponsored by an employer. The location and histologic features of all polyps were recorded. Colonoscopy to the level of the cecum was completed in 97.0 percent of the patients. RESULTS: Sixty-one patients (3.1 percent) had advanced lesions in the distal colon, including 5 with cancer, and 50 (2.5 percent) had advanced proximal lesions, including 7 with cancer. Twenty-three patients with advanced proximal neoplasms (46 percent) had no distal polyps. The prevalence of advanced proximal neoplasia among patients with no distal polyps was 1.5 percent (23 cases among 1564 persons; 95 percent confidence interval, 0.9 to 2.1 percent). Among patients with distal hyperplastic polyps, those with distal tubular adenomas, and those with advanced distal polyps, the prevalence of advanced proximal neoplasia was 4.0 percent (8 cases among 201 patients), 7.1 percent (12 cases among 168 patients), and 11.5 percent (7 cases among 61 patients), respectively. The relative risk of advanced proximal neoplasia, adjusted for age and sex, was 2.6 for patients with distal hyperplastic polyps, 4.0 for those with distal tubular adenomas, and 6.7 for those with advanced distal polyps, as compared with patients who had no distal polyps. Older age and male sex were associated with an increased risk of advanced proximal neoplasia (relative risk, 1.3 for every five years of age and 3.3 for male sex). CONCLUSIONS: Asymptomatic persons 50 years of age or older who have polyps in the distal colon are more likely to have advanced proximal neoplasia than are persons without distal polyps. However, if colonoscopic screening is performed only in persons with distal polyps, about half the cases of advanced proximal neoplasia will not be detected.

Pharmacologic treatment of the irritable bowel syndrome: a systematic review of randomized, controlled trials.

PURPOSE: To evaluate the efficacy of pharmacologic agents for the irritable bowel syndrome. DATA SOURCES: Electronic literature search of MEDLINE (1966 to 1999), EMBASE (1980 to 1999), PsycINFO (1967 to 1999), and the Cochrane controlled trials registry and a manual search of references from bibliographies of identified articles. STUDY SELECTION: Randomized, double-blind, placebo-controlled, parallel, or crossover trials of a pharmacologic intervention for adult patients that reported outcomes of improvement in global or irritable bowel-specific symptoms. DATA EXTRACTION: Qualitative and quantitative data reported on study groups, interventions, treatment outcomes, and trial methodologic characteristics. DATA SYNTHESIS: 70 studies met the inclusion criteria. The most common medication classes were smooth-muscle relaxants (16 trials), bulking agents (13 trials), prokinetic agents (6 trials), psychotropic agents (7 trials), and loperamide (4 trials). The strongest evidence for efficacy was shown for smooth-muscle relaxants in patients with abdominal pain as the predominant symptom. Loperamide seems to reduce diarrhea but does not relieve abdominal pain. Although psychotropic agents were shown to produce global improvement, the evidence is based on a small number of studies of suboptimal quality. Psychotropic drugs, 5-hydroxytryptamine (5-HT)-receptor antagonists, peppermint oil, and Chinese herbal medicine require further study. CONCLUSIONS: Smooth-muscle relaxants are beneficial when abdominal pain is the predominant symptom. In contrast, the efficacy of bulking agents has not been established. Loperamide is effective for diarrhea. Evidence for use of psychotropic agents is inconclusive; more high-quality trials of longer duration are needed. Evidence for the efficacy of 5-HT-receptor antagonists seems favorable, although more studies are needed.

Predictors of large esophageal varices in patients with cirrhosis.

OBJECTIVE: Recent guidelines recommend that all cirrhotics undergo screening upper endoscopy to identify those patients at risk for bleeding from varices. However, this practice may not be cost effective as large esophageal varices are seen only in 9-36% of these patients. The aim of this study was to determine whether clinical variables were predictive of the presence of large esophageal varices. METHODS: This is a retrospective analysis of cirrhotics who had a screening upper endoscopy during an evaluation for liver transplantation at three different centers and who had not previously bled from varices. A multivariate model was derived on the combined cohort using logistic regression. Three hundred forty-six patients were eligible for the study. RESULTS: The prevalence of large esophageal varices was 20%. On multivariate analysis, splenomegaly detected by computed tomographic scan (odds ratio: 4.3; 95% confidence interval: 1.6-11.5) or by physical examination (odds ratio: 2.0; 95% confidence interval: 1.1-3.8), and low platelet count were independent predictors of large esophageal varices. On the basis of these variables, cirrhotics were stratified into high- and low-risk groups for the presence of large esophageal varices. Patients with a platelet count of > or = 88,000/mm3 (median value) and no splenomegaly by physical examination had a risk of large esophageal varices of 7.2%. Those with splenomegaly or platelet count < 88,000/mm3 had a risk of large esophageal varices of 28% (p < 0.0001). CONCLUSIONS: Our data show that clinical predictors could be used to stratify cirrhotic patients for the risk of large esophageal varices and such stratification could be used to improve the cost effectiveness of screening endoscopy.

Cost-effectiveness analysis of hepatitis A vaccination strategies for adults.

Our objective in this study was to determine the cost-effectiveness of hepatitis A vaccination strategies in healthy adults in the United States. We constructed a decision model simulating costs and health consequences for otherwise healthy adults with respect to hepatitis A prevention. Three strategies were compared: (1) no intervention, (2) vaccination against hepatitis A, and (3) testing for antibodies to hepatitis A and vaccinating those without antibodies. Costs and probabilities were obtained from the published literature. One- and two- way sensitivity analyses were performed. Under baseline conditions, the "test" strategy cost $230,100 per life-year saved compared with the "no intervention" strategy. The incremental cost-effectiveness of the "vaccination" strategy compared with the "test" strategy was $20.1 million per life-year saved. The "test" strategy was cost-effective when the hepatitis A case fatality rate exceeded 17% (baseline 2.7%). The "vaccination" strategy was cost-effective when 1 dose of vaccine cost $7 or less (baseline $57). Under baseline conditions, neither the "test" nor the "vaccination" strategies are considered cost-effective according to current standards. Large changes in hepatitis A incidence, mortality rates, or vaccine cost are required for either of the intervention strategies to approach potentially cost-effectiveness. Such conditions may occur in areas in which hepatitis A is endemic, and/or under mass-vaccination scenarios.

Meta-analysis: when and how.

Systematic reviews have a central role in evidence-based medicine. The quantitative systematic review, also known as meta-analysis, provides a logical structure for quantifying evidence and for exploring bias and diversity in research systematically. It is essential that clinicians, educators, and researchers understand the methods that comprise this research tool, particularly the basic step-by-step process, and know when numerical pooling of data is appropriate. The essay describes how systematic reviews are best conducted and when statistical pooling of data is appropriate. Systematic reviews are scientific investigations with planned methods that use original studies as subjects and synthesize the results of multiple studies using strategies to limit bias and random error. This process requires judgments to be made explicit, and should be question driven, protocol based, reproducible, and comprehensive in scope. Meta-analysis provides a framework for research synthesis, increases power and precision, provides an overall estimate and range of effect, and identifies greater-than-expected variability among study results (heterogeneity). Meta-analysis does not remove subjectivity from the process of synthesis, identify sources of variability among studies, or obviate the need for sound, compassionate clinical reasoning. Statistical heterogeneity should be anticipated and welcomed. It forces a consideration of clinical heterogeneity as well as variation in study protocol and quality. Statistical tests for homogeneity are insensitive and do not indicate sources of heterogeneity, making such consideration imperative. The most common and popular measures of efficacy for a meta-analysis are the standardized difference between two means, the relative risk, and the odds ratio. An additional measure, the number needed to treat, with its 95% confidence interval is the most clinically useful measure of the effects of an intervention and is useful for comparing the relative effectiveness of different interventions for the same condition. Important parts of meta-analysis and sensitivity and subgroup analyses are best considered a priori and should be used to explore heterogeneity and to test for publication bias and variation in study quality.

The utility of clinical and radiographic features in the diagnosis of cytomegalovirus central nervous system disease in AIDS patients.

BACKGROUND: Polymerase chain reaction (PCR) assays of cerebrospinal fluid (CSF) for cytomegalovirus (CMV) DNA have facilitated the diagnosis of CMV-associated central nervous system disease in AIDS patients. We attempt to correlate clinical and radiographic features that are associated with CMV PCR- positivity in CSF from AIDS patients with neurologic disease. METHODS AND RESULTS: A retrospective case controlled comparison was made of CMV PCR-positive and PCR-negative patients. RESULTS: CMV PCR-positive patients were significantly more likely to have nystagmus, prior CMV retinitis, and CSF protein levels.90 mg/dL. Of patients with 0, 1, and $2 of these features, 5.6%, 55.2%, and 88.9%, respectively, were PCR-positive. Ependymal enhancement was present by magnetic resonance imaging in 9 of 12 PCR-positive, and in 8 of 30 PCR-negative patients. CONCLUSION: These clinical and radiographic features may serve as useful adjuncts toward the establishment of the diagnosis of CMV-associated neurologic disease in AIDS patients.

Patients willing to try colonoscopy without sedation: associated clinical factors and results of a randomized controlled trial.

BACKGROUND: Sedation causes most of the complications of colonoscopy. Sedation is used selectively in some countries but is routine in the United States. METHODS: Cross-sectional survey and randomized controlled trial were used to identify patient factors associated with willingness to try colonoscopy without sedation and to compare pain and satisfaction scores and willingness to return to the same physician in patients randomized to receive routine sedation versus as needed sedation. A single colonoscopist invited 250 consecutive eligible outpatients to be randomized to routine sedation versus as needed sedation. Seventeen who preferred no sedation and 163 who preferred sedation refused. Seventy accepted and were randomized. RESULTS: Male gender (odds ratio 4.33; 95% CI [2.27, 8.26]), increasing age (odds ratio for 10-year increase 1.28; 95% CI [1.01, 1.06]), and absence of abdominal pain (odds ratio 5.13; 95% CI [1.68, 15.63]) were associated with willingness to be randomized. Total colonoscopy was achieved without sedation in 94% of those who received sedation only as needed. Pain scores were higher in the sedation as needed arm. All 35 patients in the routine sedation arm were "very satisfied". In the sedation as needed arm, 31 of the 34 were "very satisfied" and 3 were "somewhat satisfied". All randomized patients said they would return to the same colonoscopist. Patients in the sedation as needed arm had less decline in blood pressure, less hypoxemia, and lower charges than those in the routine sedation arm. CONCLUSIONS: Experienced colonoscopists should consider offering colonoscopy without sedation to selected patients.

Meta-analysis and cost comparison of polyethylene glycol lavage versus sodium phosphate for colonoscopy preparation.

BACKGROUND: Although polyethylene glycol lavage solutions are widely used for colonoscopy preparation, evidence suggests that sodium phosphate is better tolerated and has similar efficacy. The purpose of this study was to compare compliance with and efficacy of polyethylene glycol and sodium phosphate using meta-analysis and to compare the cost of colonoscopy with both methods. METHODS: We used Medline to identify all randomized controlled trials comparing the two preparations. Study methods were evaluated, and quantitative data were abstracted independently, including inability to complete the preparation and preparation quality, rated as adequate or excellent. A random effects model was used to calculate the pooled relative risk. Direct costs and literature-based probability estimates were used to compare costs. RESULTS: Among 1286 subjects from eight colonoscopist-blinded trials, the pooled relative risk of inability to complete the preparation was 0.23 (95% CI [0.18-0.28]) in favor of sodium phosphate. Although the best estimate of the relative risk for an adequate quality preparation revealed therapeutic equivalence (relative risk = 1.06: 95% CI [0.95-1.19]), an excellent quality preparation was more likely with sodium phosphate (relative risk = 1.72: 95% CI [1.16-2.53]). Assuming reexamination rates from published literature of 3% and 8% for sodium phosphate and polyethylene glycol, respectively, direct costs of colonic examination were $465 and $503. There were no clinically important adverse effects with either method. CONCLUSION: The results suggest that sodium phosphate is as effective and less costly, with a more easily completed preparation, compared with polyethylene glycol and is the preferred method of preparation for colonoscopy for certain patient subgroups.