For patients and doctors, split-dose colonoscopy prep is better

Last Updated: 2016-07-21

By Lorraine L. Janeczko

NEW YORK (Reuters Health) - Split-dose (SPD) bowel preparation before colonoscopy is more convenient for patients and improves the detection rates of some polyps, new research reports.

"Small-volume, split-dose preparation resulted in decreased overall intensity and duration of bowel movements, less patient inconvenience in terms of sleep disturbance, and no difference in travel disruption compared to single dosing. Perhaps most importantly, split dosing also resulted in a fourfold increase in the sessile-serrated polyp detection rate," said lead author Dr. Nicholas Horton of the Cleveland Clinic in Ohio.

"Our study provides further compelling data in support of the previously described national recommendation for split-dose bowel preparations," he told Reuters Health by email.

As reported online July 5 in the American Journal of Gastroenterology, Dr. Horton and colleagues randomly assigned patients to receive either two-liter single-dose or SPD (divided into one-liter SPD1 and one-liter SPD2) bowel preps. The patients answered questions about the onset, duration, cessation, and intensity of their bowel movements, and any sleep disruptions or travel disruptions on the way to the endoscopy center. The researchers recorded colon cleansing quality and polyp histology.

Except for cirrhosis of the liver, which was more common in the single-dose group, both groups were similar in age, indication for procedure, gender, and percentage of patients with specific major comorbid diseases.

Overall, 341 patients with a mean age of 54, who were scheduled for colonoscopy, were enrolled in the study. All were instructed to take two liters of polyethylene glycol electrolyte lavage solution with ascorbic acid (MoviPrep; Salix Pharmaceuticals, Raleigh, North Carolina). Roughly half took the entire quantity the evening before their colonoscopy, and the other half took the first half-dose (SPD1) the evening before and the second half-dose (SPD2) the day of the procedure.

The time to onset of first bowel movement after starting to drink the prep was longer with SPD1 (P=0.019) and shorter with SPD2 (P<0.001) compared with single-dose prep. Bowel movements began within 60 minutes in 91% of patients drinking SPD2, compared with 64% of patients in the single-dose group and 51% taking SPD1.

After dosing, 92% of single-dose patients and 66% of SPD1 patients had clear bowel movements (P<0.001), compared with 97% of SPD2 patients (P=0.028 vs single-dose).

The total duration (P=0.041) and intensity (P<0.001) of bowel movements were greater with the single dose.

More patients in the single-dose group woke up for bowel movements (65.9% vs 48.8%, P<0.003). No differences in the need to stop driving on the way to the procedure were reported. Bowel prep quality was reported to be better with SPD (P<0.001).

The researchers found no difference in adenoma detection rate, but the sessile-serrated polyp detection rate was greater with SPD (9.9% vs 2.4%, P=0.004).

The authors admit that the single-blind design allowed the endoscopist to know which dosing regimen patients received, and that most of the data were self-reported.

"A number of past studies have shown that split-dose bowel preparation leads to improvements in visualization of the colon and increased adenoma detection rates, and the United States Multi-Society Task Force on Colorectal Cancer already recommends split-dose rather than single-dose regimens," Dr. Horton said.

Unfortunately, he added, many doctors and patients hesitate to use split-dose preps, possibly to avoid what they perceive as disruption to the patient's sleep and travel caused by the timing of the second dose.

"We hope that our findings will help reassure patients and physicians about patient convenience with split-dosing. We also hope that our detailed data on bowel movement kinetics induced by bowel preparation will help guide clinician-patient conversations about bowel preparation expectations," he said.

Dr. D. Kim Turgeon, associate professor of internal medicine at the University of Michigan Health System in Ann Arbor, said in an email, "Prep is a very important issue and patients need to understand that having an excellent prep behooves them. As with almost everything, though, one size does not fit all."

"In general, split-prep dosing is better, and that is what we try to use at the University of Michigan," added Dr. Turgeon, who was not involved in the study.

Salix Pharmaceuticals funded the study but was not involved in its design, data collection, analysis or interpretation, or with the writing of the paper.

These findings were presented at Digestive Disease Week 2016 in San Diego.

SOURCE: http://bit.ly/29QidtW

Am J Gastroenterol 2016.