Colonoscopy in children and young adults is performed by gastroenterologists for a variety of indications, including but not limited to evaluation of rectal bleeding, chronic diarrhea, family history of polyposis syndromes and surveillance for colon cancer in patients with inflammatory bowel disease [1–4]. A successful bowel preparation that enables clear visualization of the intestinal mucosa is essential to diagnose and treat the underlying pathology. Currently, gastroenterologists use a variety of colon cleansing preparations, but Polyethylene Glycol (PEG) 3350 given for three to four days appears to be standard [5–8]. Though it is well tolerated, safe and effective [5, 9–11], the duration of preparation may cause disruption to the routine and missed school days. To date, there is limited data that shows efficacy of a shorter duration of bowel preparation with PEG [12–14]. This study aims to compare the efficacy and safety of a one-day preparation with that of a three-day preparation with PEG 3350 as preparation for colonoscopy in children and young adults.

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 3^rd 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 [5]. 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.

Review of serologic evaluation showed 2/18 in the one-day group and 2/14 in the three-day group had slightly low osmolality (277 milliosmoles/kg and 278 millosmoles/kg in the one-day group and 274 milliosmoles/kg and 275 millosmoles/kg in the three-day group) on pre-bowel preparation labs performed as part of the study. These were not associated with any clinical symptoms. Similarly, 5/18 in the one-day and 4/14 in the three-day group had abnormal serology following the preparation. In the one-day group, one patient had an elevated osmolality of 315, two patients had a low osmolality of 275 & 277 and two patients had low serum bicarbonate of 19 & 20. In the three-day group, two patients had low osmolality of 275 & 277 and two had low bicarbonate of 15 & 17. These serologic derangements were not associated with any clinical symptoms and the incidence of these abnormalities was not statistically significantly different between the two groups.

The importance of a safe, easily tolerable and effective colonoscopy preparation, particularly in the pediatric population, is paramount for both diagnostic and, at times, therapeutic reasons. This is important for the patient in terms of acceptability and missed days of school and his/her parents, in terms of taking time off of work. This is one of the first prospective studies evaluating the use of PEG 3350 without electrolytes for a one-day bowel preparation for colonoscopy in children and young adults in comparison with the three-day preparation. The data from our study indicates that the safety, efficacy and tolerability of bowel preparation with PEG given one-day are not inferior to that of three-day preparation.

At our institution, PEG is usually used as a three day bowel preparation in children. A recent retrospective study by Adamiak et al. reported an efficacy of 93% with one-day use of PEG for bowel preparation in children [12]. In our patient population, a similar efficacy (100%) with one-day preparation was noted.

The side effects reported in both groups in this study have previously been reported with use of PEG for bowel preparation as well as for other indications such as constipation, fecal impaction and bowel irrigation. Although there was a slightly higher incidence of side effects in the one-day group compared to three-day group, they were well tolerated and were not statistically significant. Following completion of the bowel preparation, low serum bicarbonate and low osmolality were noted in two patients in both groups, but they were of no clinical significance in this study. As the patients were asymptomatic, repeat serologic evaluation was not undertaken at a later time to document normalization.

In the one-day group, 89% of patients reported that the preparation was easy or tolerable and 72% completely took the prescribed amount of PEG based on their weight. Those that ingested only part of the preparation reported that their stools were clear and they did not feel that it was necessary to take the remaining PEG. This did not affect the quality of bowel cleansing.

The small sample size is an important limitation of our study. This was due to a slow recruitment rate at our institution. Another possible limitation of this study is evaluation bias by the gastroenterologist evaluating the degree of bowel cleaning at colonoscopy. However, this has been eliminated by having an independent gastroenterologist (blind reviewer), not involved in the study, review the endoscopic images and grade the preparation.

The data from our study suggests that bowel preparation with PEG given as a one-day preparation is tolerable, safe and effective, and is not inferior to a three-day preparation. A shorter duration of bowel preparation will increase compliance, reduce the number of school days missed for children and workdays missed for their parents. However, future studies with a larger sample size are necessary to confirm these results. Furthermore, consideration for split dose preparation, as is becoming the standard in the adult population undergoing colonoscopy, may be considered [15–17] as a part of future studies.