Oral Sodium Phosphate Versus Polyethylene Glycol-electrolyte Lavage Solution For Colonoscopy Preparation: A Cochrane Systematic Review

Background: Satisfactory colonoscopy preparation requests for reliable quality of colon cleansing, good tolerance of patients, safety and economy. As new methods of cleansing, oral sodium phosphate (NaP) and polyethylene glycol-electrolyte lavage solution (PEG-ELS) haven't been used widely in China.Objectives: To evaluate which of the two methods is superior in the aspects of cleansing efficacy, tolerance of patients, and safety in clinical practice. Materials and Methods: A Cochrane systematic review of randomized controlled trials of NaP versus PEG-ELS for colonoscopy preparation was performed. Trials were identified by searching for Cochrane Controlled Trials Register, Medline, Embase, Chinese Biological Medicine Database, Chinese VIP Database and Chinese EBM Database. We handsearched the data from the references of all included trials, the proceeding of correlated conferences, the journals not included by the database above and the material offered by relevant pharmaceutical company. Two reviewers independently assessed thequality of the included trials and extracted data independently. The following outcomes were assessed: rate of excellent and good (adequate) cleansing quality of all colon segments, rate of excellent cleansing quality of all colon segments, rate of adequate cleansing quality of different segment of colon, percentage of patients whose cecum was reached, percentage of patients who thought the preparation they used was easy to accept, percentage of patients who thought the taste of their solution or pills was tolerable, percentage of patients who hadn't finished their prescribed regimen, percentage of patients who would choose the same preparation next time, rate of adverse events and change of serum electrolyte after preparation. Revman 4.1 software was used to perform statistical process.Results: Eighteen trials involving 3668 patients were included. Meta-analysis was performed. (1) About efficacy, there was a non-significant trend in favor of NaP in the rate of adequate cleansing quality and the rate of excellent quality of all colon segments (p>0.05). The rate of adequate cleansing quality in right colon of NaP was lower than PEG-ELS (p=0.00002). Sub-group analysis was performed. NaP tablet had higher rate of adequate cleansing quality (p=0.01). Two-day, divided-dose oral sodium phosphate was superior in the rate of adequate cleansing quality (p=0.005). (2) About tolerance, NaP was superior in the percentage of patients who thought the preparation they used was easy to accept, the percentage of patients who hadn't finished their prescribed regimen and the percentage of patients who would choose the same preparation next time (p<0.05). (3) About safety, the rate of abdominal cramps or pain and the rate of abdominal fullness or bloating in NaP group were lower (p<0.05), but the rate of dizziness is higher (p=0.01) comparedwith PEG-ELS. Meta-analysis results showed NaP group had higher serum sodium and phosphorus (p<0.05), compared with PEG-ELS. Conclusions: Two-day, divided-dose .oral NaP or using NaP tablet was superior compared with PEG-ELS in cleansing quality of all colon segments. Patients favored NaP in tolerance. The adverse effect symptoms in NaP group is less except dizziness. The change of serum electrolyte especially phosphorus after preparation was more obvious in NaP group. NaP solution was economic and effective and might be preferable for patients who hadn't congestive heart failure, renal insufficiency, ascites or abnormal serum electrolyte. But because the quality of the included trials wasn't high and the coincidence of the standards of excluding participants and assessing outcomes among the trials was poor, we should adopt the conclution cautiously. More trials with sound methodology, uniform excluding standards and self-report questionnaires are required.