Bowel preparation in diabetic patients undergoing colonoscopy

We read with interest the article by Alvarez-Gonzalez et al. regarding bowel preparation in patients with diabetes mellitus undergoing colonoscopy. In these patients, who can be difficult to prepare, the proposed multifactorial strategy improved bowel preparation compared with the conventional bowel preparation protocol (CBP) without differences in safety or tolerability (P = 0.014; risk ratio 3.1, 95 % confidence interval [Cl] 1.2 – 8) [1].

Non-insulin-dependent diabetes mellitus, which is an independent risk factor for inadequate bowel preparation [2], increases the prevalence of gastrointestinal symptoms and the risk of colon cancer. We know that the quality of colonoscopy preparation impacts on the detection of suspected colonic neoplasia. A previous study suggested that, because of constipation, optimal bowel cleansing is poorer in diabetics with autonomous neuropathy than in those without autonomous neuropathy and controls [3].

The multifactorial strategy, proposed by the authors to decrease the rate of inadequate bowel preparation, is made up of educational intervention, with special attention to dietary recommendations, and dose adjustment of blood glucose-lowering agents.

On univariate analyses, the trial from Alvarez-Gonzalez et al. shows that constipation, as well as CBP, Eastern Cooperative Group (ECOG) performance status, Charlson Co-morbidity Index, and late complications of diabetes, is associated with inadequate bowel preparation. While on multivariate analysis, independent predictors of inadequate bowel preparation in patients with diabetes are CBP group (odds ratio [OR] 3.5, 95 %CI 1.2 – 10.4) and ECOG performance status > 1 (OR 3.8, 95 %CI 1.4 – 10.2).

One strategy for improving bowel preparation in diabetes mellitus patients with constipation or late complications could be the administration of pyridostigmine. Pyridostigmine is a reversible cholinesterase inhibitor that prevents the degradation of acetylcholine, so increasing its concentration in the synapses and facilitating the transmission of impulses from the neuromuscular junction. It is used in the treatment of severe constipation because it improves colonic transit, without causing blood sugar imbalances [4].

Therefore, we suggest including oral administration of pyridostigmine in a multifactorial strategy, along with educational intervention and dose adjustment of blood glucose-lowering agents, as proposed by Alvarez-Gonzalez et al., in patients with constipation from bowel motor neuropathy, including those with diabetes. In this way the rate of inadequate bowel preparation could be decreased. The oral administration of pyridostigmine could be a useful trick for bowel preparation in patients with slow intestinal transit time.

Current clinical guidelines for colonoscopy preparation [5] do not include specific strategy for patients in whom bowel preparation is difficult. We believe a multifactorial strategy should be used as a solution to reducing the rate of inadequate bowel preparation in these patients. Pyridostigmine bromide orally, at a dose of 60 mg or more three times daily, could be administered for constipation in these patients, especially during bowel preparation. Although the role of pyridostigmine in a multifactorial strategy remains to be demonstrated by specific trials, we suggest it could be used for patients with slow intestinal transit.

• References

• 1 Alvarez-Gonzalez MA, Flores-Le Roux JA, Seoane A. et al. Efficacy of a multifactorial strategy for bowel preparation in diabetic patients undergoing colonoscopy: a randomized trial. Endoscopy 2016; 48: 1003-1009
• 2 Taylor C, Schubert ML. Decreased efficacy of polyethylene glycol lavage solution (golytely) in the preparation of diabetic patients for outpatient colonoscopy: a prospective and blinded study. Am J Gastroenterol 2001; 96: 710-714
• 3 Ozturk NA, Gokturk HS, Demir M. et al. The effect of autonomous neuropathy on bowel preparation in type 2 diabetes mellitus. Int J Colorectal Dis 2009; 24: 1407-1412
• 4 Bharucha AE, Low P, Camilleri M. et al. A randomised controlled study of the effect of cholinesterase inhibition on colon function in patients with diabetes mellitus and constipation. Gut 2013; 62: 708-715
• 5 Johnson DA, Barkun AN, Cohen LB. et al. Optimizing adequacy of bowel cleansing for colonoscopy: recommendations from the US Multi-Society Task Force on Colorectal Cancer. Am J Gastroenterol 2014; 109: 1528-1545