Interventional gastroenterology

Queensland study shows the best way to avoid inadequate bowel preparation

A screening tool that identifies patients at high risk of poor bowel preparation has been developed by gastroenterologists in Queensland, who say it can be used to target patients for more time-intensive counselling.

Up to a third of patients undergoing colonoscopy have inadequate bowel preparation, leading to poor polyp detection, longer procedure times and sometimes the need for a repeat procedure, according to Professor Gerald Holtmann and colleagues at the Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Brisbane.

Since it is very resource intensive to provide face-to-face counselling on bowel preparation for the thousands of patients undergoing colonoscopy, Professor Holtmann and colleagues investigated which patients were most likely to need targeted interventions based on factors identified in a cohort of 76 consecutive outpatients with poor bowel preparation.

Prior to the study most patients undergoing colonoscopy received standard bowel preparation education by a pre-endoscopy nurse and educational literature. Before the procedure they had a PEG split-preparation (or sodium picosulfate split-preparation), with the standard bowel cleansing protocol  of 3 L of PEG solution. Patients were also advised to follow a low fibre diet followed by a liquid-only diet prior to  undergoing colonoscopy. 

When compared with 76 age- and gender-matched patients with good preparation from the same procedure lists the researchers found that use of opioids or other constipating agents and low socioeconomic status were significant risk factors for inadequate preparation  (Odds Ratio 2.88 and 2.43 respectively). As expected, other significant risk factors  included poor adherence (smaller volume of bowel preparation liquid consumed) and poor tolerability (complaining of bad taste).

However, other factors such as diabetes, renal function, obesity and constipation did not prove to be significant risk factors.

The identified risk factors were put into a risk tool called B-Prism (Bowel Preparation Screening and Mitigation), which predicted poor preparation with 59% sensitivity and 76% specificity (AUC = 0.74, cutoff point = 0.51). 

When implemented in practice, the B-Prism tool resulted in much more targeted use of educational counselling for bowel preparation: only 33% of 1663 patients underwent counselling post-intervention compared to 62% of 1098 patients being counselled in the same time period prior to use of the screening tool.

Despite this, no negative impact on the quality of bowel preparation was noted, with a 5.73%  and 6.12%  incidence of poor preparation observed for the respective time periods,” the researchers noted.

About 65% of patients had at least one risk factor for a poor bowel preparation according to the tool, and among these the incidence of poor quality of bowel preparation was 8.82% compared with 5.56% in patients with no risk factors, a non-significant difference.

The authors said their study showed that for many patients undergoing colonoscopy printed educational material alone would  be sufficient to achieve the desired adequate bowel preparation, and the risk tool would help target the use of resource- intensive and time-intensive face-to-face and phone interventions to high risk patients.

“Identifying and specifically targeting education at patients with these risk factors appears to facilitate more efficient use of education resources in endoscopy,” they concluded. 

The findings are published in the Journal of Clinical Gastroenterology.

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