One way that doctors and researchers have improved colon preparation is the implementation of the split dose regimen. Instead of consuming a large volume of cleansing solution the night before your colonoscopy, you now can split the dose into two halves. One dose is taken the night before your colonoscopy, and the second dose is taken about four to five hours before the procedure (Source: NCBI).
The split-dose bowel preparation has many benefits, such as improved patient acceptability and better cleansing. The U.S Multi-Society Task force recommends the split-dose preparation specifically because it has proven to increase adenoma detection rates (ADR). Recent studies also show that split-dose preparation is associated with a higher detection rate for sessile serrated polyps during colonoscopy exams. A sessile serrated polyp is a premalignant, flat lesion that is mostly seen in the cecum and ascending colon. These polyps are thought to lead to colon cancer through a different pathway than most colorectal cancers.
A randomized study led by Nicholas Horton, MD, of the Cleveland Clinic, found that the detection rate for sessile serrated polyps was 9.9 percent with split-dose preparation compared to 2.4 percent with single-dose preparation. A total of 17 percent of the lesions were identified as sessile serrated polyps in the split-dose group compared with only 4.4 percent in the single-dose group.
Horton and his colleagues studied 341 patients whose mean age was 54. One group consumed 2 liters of bowel prep solution as a single preparation the night before their colonoscopy. Another group consumed half the solution on the night before and half on the morning of the colonoscopy. Both groups were instructed to only have clear liquids.
Overall, there was little difference between the two groups in the detection rates of polyps and adenomas or in the location, size or number of polyps identified. Polyp detection rates in the single-dose and split-dose groups were 55 percent and 59 percent, respectively, while adenoma detection rates were 32 percent and 37 percent. Any proximal polyps were identified in 67 percent of the single dose and 61 percent of the split-dose groups, respectively, while any distal polyps were detected in 66 percent and 70 percent.
The split-dose preparation certainly does perform as well as the single-dose preparation. One of Horton’s colleagues, John Vargo, M.D., MPH, who was not involved in the study, concurred with Horton’s findings. He said Horton's group "found that the split dose benefited the patients in several important ways, such as allowing more flexibility in scheduling and most significantly, resulting in a higher detection rate of sessile serrated polyps. I think that their findings, along with previous research, will encourage many healthcare providers to reconsider making patients consume the bowel preparation in one large dose," he said (Source: MedPageToday).