Improved Bowel Preparation Method for Colonoscopy Based on Different Risk Stratification

Improved Bowel Preparation Method for Colonoscopy Based on Different Risk Stratification：a Multicenter, Endoscopist-blinded Randomized Controlled Trial

The purpose of this study is to evaluate the efficacy of polyethylene glycol（PEG） combined with lactulose for bowel preparation before colonoscopy in low-risk patients and high-risk patients.

The quality of bowel preparation is crucial for colonoscopy. Some high-risk factors for inadequate bowel preparation have been identified , including age >70, previous colon surgery, constipation, diabetes, Parkinson's disease, history of stroke or spinal cord injury, prior history of inadequate bowel preparation, body mass index (BMI) >25, use of tricyclic antidepressant or narcotics. Patients were considered as high risk if they have any of the above factors and considered as low risk if they did not have any of these risk factors.This is a multicenter, endoscopist-blinded study to compare the efficacy of PEG combined with lactulose and PEG alone in bowel preparation. In colonoscopy procedures, endoscopists who were blinded to the intervention evaluated the overall quality of colonoscopy cleaning according to the Boston Bowel Preparation Scale. Patients' tolerance, defecation, adverse events and adenoma detection rate (ADR) were also evaluated.

Inclusion Criteria:

- Adults undergoing colonoscopy.

Exclusion Criteria:

• 1.presence of any contraindications for colonoscopy (gastrointestinal obstruction or perforation,severe acute inflammatory bowel disease,toxic megacolon,severe heart failure,unable to swallow,severe heart failure,etc);
• 2.Patients with galactosemia;
• 3. hypersensitivity to any of the ingredients;
• 4.Pregnancy or lactation;
• 5.Use of lactulose,prokinetic agents or purgatives within 7 days;
• 6.Unwilling to sign informed consent.