A prospective, randomized controlled study was conducted at St. John Hospital and Medical Center in Detroit, MI between February 2008 and February 2010, after obtaining Institutional Review Board (IRB) approval from the St. John Hospital IRB, which provides oversight for both the scientific and ethical aspects of research studies conducted at our facility. Children between 2 and 21 years of age undergoing elective colonoscopy were enrolled into the study. The exclusion criteria for this study were a history of allergy to PEG, fecal impaction, known electrolyte abnormalities, as well as renal and metabolic diseases. Written consent from subjects or their parents was obtained at the time of enrollment.
Subjects were randomly assigned to either a one-day or a three-day preparation group. Those in the one-day group were instructed to take 4.5gm/kg/day PEG 3350 up to a maximum dose of 255 g and those in the three-day group to receive 1.5 g/kg/day, up to a daily maximum dose of 85gm and total dose of 255 g. Written instructions were provided to take PEG with any clear liquid. Subjects were asked to take 1 scoop (17 g) of PEG mixed with 8 oz. of clear liquid every 30 minutes. Those under 7 years of age were asked to take ½ scoop (8.5 g) mixed with 4 oz. of clear liquid every 30 minutes. Subjects in the three-day group were instructed to take a regular diet for the first two days of preparation and a clear liquid diet on the 3rd day. Subjects in the one-day group were instructed to take clear liquid diet on the day of bowel preparation. Subjects in both groups were asked not to take anything by mouth (NPO) eight hours before procedure except sips of water up to three hours before procedure.
Demographic data such as age, gender, race, ethnicity and weight were collected. Indications for colonoscopy were recorded. Subjects were given written instructions regarding the total amount of PEG to be taken over one-day or three-days, what to take it with, in terms of quantity and frequency, and diet while undergoing bowel preparation.
Subjects were asked to report how tolerable (easy, tolerable or difficult) the preparation was and whether they completely took PEG as prescribed. If the patient did not take the entire prescribed regimen, reasons for not completing the preparation were elucidated. Subjects were also asked if they were willing to take the preparation again in the future, if they had to. Serum electrolytes, blood urea nitrogen (BUN), creatinine and serum osmolality were checked before and after the bowel preparation to monitor the safety of the preparation. While undergoing the preparation, a stool diary consisting of stool frequency, color and consistency was completed by all subjects.
At the time of colonoscopy, the pediatric gastroenterologist (HL) involved in the study, who was blinded to the preparation given, graded the degree of bowel cleansing as poor, fair, good or excellent depending on the type and amount of liquid debris or stool present. Endoscopic images were also evaluated by a blind reviewer (a second pediatric gastroenterologist, MEB). All segments of the colon were evaluated (cecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum), with photographs of each segment reviewed independently by the primary endoscopist and the blinded reviewer. A previously described grading system was used for this study . A grading of excellent required no stool or small amount of thin fecal fluid to be seen. A good grading was characterized by liquid fecal matter that could be removed by suction easily. A grading of fair meant that thick stool was present, requiring suction with water lavage. A grading of poor required solid stools present with poor visualization of the mucosa. A grading of good or excellent was acceptable for the evaluation of the colonic mucosa and a repeat colonoscopy was not required. Primary outcomes measured were efficacy, safety and tolerability of PEG given one-day vs. three days for bowel preparation for colonoscopy.
Frequency and descriptive statistics were calculated. Associations between categorical variables and treatment group were measured by Chi-square or Fisher’s exact tests. Differences between groups on continuous variables were assessed using Student’s t-tests. P values < 0.05 were considered to indicate statistical significance. SPSS version 12.0 was used for statistical analysis.
Funding for this study was provided by the St. John Hospital & Medical Center Graduate Medical Education Research Committee.