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.

[1]  T C Chalmers,et al.  A comparison of statistical methods for combining event rates from clinical trials. , 1989, Statistics in medicine.

[2]  C. Mixter.  A complication of Golytely preparation. , 1986, Gastrointestinal endoscopy.

[3]  J. Nogueras,et al.  Prospective, randomized, endoscopic-blinded trial comparing precolonoscopy bowel cleansing methods , 1994, Diseases of the colon and rectum.

[4]  K A L'Abbé,et al.  Meta-analysis in clinical research. , 1987, Annals of internal medicine.

[5]  J. Barthel,et al.  Prospective, randomized trial comparing a new sodium phosphate-bisacodyl regimen with conventional PEG-ES lavage for outpatient colonoscopy preparation. , 1995, Gastrointestinal endoscopy.

[6]  E. Keeffe.  Colonoscopy preps: what's best? , 1996, Gastrointestinal endoscopy.

[7]  S. Pocock,et al.  Can meta-analyses be trusted? , 1991, The Lancet.

[8]  N. Laird,et al.  Meta-analysis in clinical trials. , 1986, Controlled clinical trials.

[9]  W G Paterson,et al.  A randomized prospective trial comparing oral sodium phosphate with standard polyethylene glycol-based lavage solution (Golytely) in the preparation of patients for colonoscopy. , 1990, The American journal of gastroenterology.

[10]  K. Khanduja,et al.  Colonoscopic bowel preparations—Which one? , 1995, Diseases of the colon and rectum.

[11]  R. Rosenthal.  The file drawer problem and tolerance for null results , 1979 .

[12]  R. Horwitz,et al.  Resolving conflicting clinical trials: guidelines for meta-analysis. , 1988, Journal of clinical epidemiology.

[13]  J. Marshall,et al.  Short report: prospective, randomized trial comparing a single dose sodium phosphate regimen with PEG–electrolyte lavage for colonoscopy preparation , 1993, Alimentary pharmacology & therapeutics.

[14]  J. Fordtran,et al.  Development of a lavage solution associated with minimal water and electrolyte absorption or secretion , 1980 .

[15]  W. G. Cochran.  The combination of estimates from different experiments. , 1954 .

[16]  G. Elta,et al.  Single-day, divided-dose oral sodium phosphate laxative versus intestinal lavage as preparation for colonoscopy: efficacy and patient tolerance. , 1995, Gastrointestinal endoscopy.

[17]  D L Sackett,et al.  An assessment of clinically useful measures of the consequences of treatment. , 1988, The New England journal of medicine.

[18]  P. Bjerregaard,et al.  Oral sodium phosphate versus sulfate-free polyethylene glycol electrolyte lavage solution in outpatient preparation for colonoscopy: a prospective comparison. , 1996, Gastrointestinal endoscopy.

[19]  H. El‐Serag,et al.  Colonic mucosal abnormalities associated with oral sodium phosphate solution. , 1996, Gastrointestinal endoscopy.

[20]  J. Marshall,et al.  Prospective, randomized trial comparing sodium phosphate solution with polyethylene glycol-electrolyte lavage for colonoscopy preparation. , 1993, Gastrointestinal endoscopy.

[21]  S. Achem,et al.  A comparison of the effectiveness and patient tolerance of oral sodium phosphate, castor oil, and standard electrolyte lavage for colonoscopy or sigmoidoscopy preparation. , 1993, The American journal of gastroenterology.

[22]  H. Keller,et al.  Prospective randomized study of preoperative bowel cleansing for patients undergoing colorectal surgery , 1994, The British journal of surgery.