Low-residue diet before colonoscopy may achieve better bowel prep quality than clear liquid diet

Liz Meszaros, MDLinx

Digestive Disease Week® (DDW)

San Diego, California, United States | May 21-24, 2016


San Diego, CA, May 18, 2016—Prior to colonoscopy, a single-day, low-residue diet (LRD) may improve bowel preparation quality—as well as patient tolerance—compared to a clear, liquid diet (CLD), according to researchers here at Digestive Disease Week 2016.

Take-home messages

  • A 1-day, low-residue diet may improve bowel preparation quality compared with a clear, liquid diet, and may even be superior.
  • A full 97% of patients on the low-residue diet reported their satisfaction with the diet compared with 46% of those in the clear liquid diet group.

“Colon cancer can be prevented by colonoscopy, and a lot of people are not having colonoscopies for many reasons. One of the reasons that is often quoted is the difficulty with the procedure for bowel preparation. One component of that is the dietary restriction that patients have to go through on the days before colonoscopy. Sometimes that is kind of uncomfortable for patients. Patients are often fatigued and hungry,” said lead author Jason B. Samarasena, MD, associated clinical professor of medicine, division of gastroenterology and hepatology, University of California—Irvine, Long Beach, CA.

“I think there are other options, such as an LRD, which has been used in other countries on the day before colonoscopy with much success with cleaning the colon and having adequate bowel preparation at the time of colonoscopy, which is a lot less restrictive and more comfortable for patients,” he added.

Dr. Samarasena and colleagues conducted this multicenter, randomized, single-blind, prospective trial in patients who underwent outpatient colonoscopy at a tertiary care center and a veterans’ administration hospital. They randomized patients to either consume a CLD for the whole day prior to colonoscopy, or a planned LRD. Both groups consumed 4F split-dosed polyethylene glycol electrolyte lavage solution (PEG-ELS).

“An LRD is very similar to a low fiber diet,” explained Dr. Samarasena. “Low-residue foods essentially digest very quickly, they liquefy very quickly in the small intestine, and there aren’t a lot of large particles left in the colon after one consumes an LRD, making it easier for a bowel preparation agent to flush any kind of residual food or stool in the colon out.”

Examples of foods that comprise an LRD and were used in this study include scrambled eggs, white bread, butter, chicken breasts, chicken nuggets, pretzels, and even macaroni and cheese.

Researchers defined an adequate preparation as a BBPS < 6 and evaluated all preparations, as well as hunger and fatigue both pre- and post-procedure, nausea, vomiting, bloating, abdominal cramping, and overall discomfort. After the procedure, they evaluated patient satisfaction with the diet, their willingness to repeat the same preparation, and overall experience.

From November 2014 to November 2015, they enrolled 83 patients (mean BPPS: 7.98 for LRD group, and 7.54 for CLD group). In the LRD group, researchers found a significantly greater number of adequate preparations compared with the CLD group (P=0.05). In addition, they found that evening hunger scores before the purgative intake were significantly lower in the LRD group compared with the CLD group (3.5 vs 6.9, respectively; P=0.001), as were morning post-prep fatigue scores (3.5 vs 6; P=0.01).

Nausea, vomiting, bloating, abdominal cramping, and overall discomfort were not significantly different between the groups, but more patients on the LRD prep reported their satisfaction with the diet compared with those in the CLD group (97% vs 46%, respectively; P < 0.001).

“There’s a lot of data out there about LRD. In the US, we’ve been over-restrictive with the diet with clear liquids. This is another study that adds to that data pool showing that LRD is as good as, and potentially even better than, clear liquids. Now we can hopefully help patients more with their bowel preparation process for it to be not such an uncomfortable process,” said Dr. Samarasena.

“Hopefully, that will encourage patients to have colonoscopies and repeat their colonoscopies if they have to. Because at the end of the day, we just want to prevent colon cancer, and we want good quality preparations so we can find those polyps and remove them,” he concluded.