Retrospective case-control study indicates that dialysis does not impact bowel preparation scores

Inadequate bowel preparation (BP) negatively affects the diagnostic performance of a colonoscopy. Most of the trials assessing adequacy of bowel preparation regimens excluded patients affected by chronic kidney disease (CKD), especially patients on dialysis. This study aimed to 1/ assess the impact of dialysis on BP quality and adenoma detection rate (ADR) and 2/ to identify factors related to quality of BP. Methods: We retrospectively compared patient-specific, preparation-specific (preparation solution, preparation regimen (split-dose vs. one-day preparation, out-patient preparation) and colonoscopy-specific data (indication, BBPS, sedation type, presence of adenoma or cancer) between 79 patients on dialysis and 158 matched controls. Adequate BP was defined as a BBPS score of ≧2 in every colonic segment. Significant contributors to BP were assessed by logistic regression. Results: Despite matching, dialysis patients were significantly older (69.0±11.9 vs 64.2±14.6, P=0.008) and less frequently women (30% vs 52%, P=0.002). There was no significant difference in BP or ADR between patients on dialysis and controls (85% vs 89%, P=0.39 and 35% vs 35%, P=1.00 resp.). Older age (P=0.03), lower BMI (P=0.03), type of BP regimen (P<0.001), outpatient preparation (P=0.03) and residency in residential care (P=0.05) were significantly associated with BP adequacy. According to the logistic regression model, split-dose regimen was the main predictor of adequate BP (P<0.001, OR 3.1 (1.65-5.81)). Conclusion: Safe and adequate BP is achievable in dialysis patients. Bowel preparation regimen rather than treatment by dialysis influences BP quality. Split-dose preparation remains the most important determinant of adequate BP for colonoscopy, irrespective of the regimen.