Optimizing the Quality of Bowel Preparation in the Difficult to Prep Population: A Systematic Review

Abstract

Introduction: Patients with comorbid conditions are often prone to inadequate preparations, which may limit detection of pre-cancerous or cancerous lesions. A “one-prep approach” may limit efficacy and lead to early repeat colonoscopy. Our aim was to conduct a systematic review of current studies evaluating patients at high-risk for an inadequate preparation. Methods: A systematic review was conducted in MEDLINE up to May 2016. Inclusion criteria: (i) age ≥ 18 (ii) studies assessing patients with comorbidities (iii) bowel preparation quality as the main outcome. Exclusion: (i) non-colonoscopy studies (ii) studies only evaluating average-risk or low-risk patients. Results: The search yielded 1,028 studies, 56 were reviewed and assessed for eligibility of which 35 met inclusion and exclusion criteria. Eleven studies evaluated the elderly, (6) constipation, (6) patients with poor preparations, (3) inflammatory bowel disease (IBD), (3) diabetes, (1) congestive heart failure (CHF), (1) cirrhosis, (1) chronic kidney disease (CKD), (1) Lynch cohort, (1) obesity, and (1) spinal cord injury. Among patients with CHF or cirrhosis a ≥3L polyethylene glycol (PEG) solution was used. Cohorts with constipation had sodium phosphate (NaP) +/- probiotics or low/high volume PEG solutions. Diabetics received a 4L PEG + mg citrate, 6L PEG or NaP. Elderly patients received picosulfate, low/high volume PEG or NaP. In patients with IBD, castor oil, senna, high/low volume PEG solutions were used. A pilot study assessed oral sodium sulfate among patients with CKD and 4L PEG + adjuvants vs. NaP split dose was assessed in patients with Lynch. Sodium picosulfate was assessed in obesity and oral sodium phosphate in patients with spinal cord injuries. Among patients with poor preparation colonoscopy enemas, low or high volume PEG and irrigation devices were utilized. Conclusion: Patients with constipation may benefit from a high volume PEG solution with adjunctive probiotics or magnesium citrate. A low or high volume PEG solution may provide effective preparations among the elderly and patients with IBD. Among patients with a prior or current poor preparation during colonoscopy, administration of high volume PEG solution the day after, enemas introduced during colonoscopy or use of irrigation devices may improve preparation quality. Additional, studies are needed among patients with CHF, cirrhosis, renal failure, spinal cord injuries, obesity and those receiving medicines, which may alter colonic motility.