Objectives: The aim of the present study was to compare, in a prospective and blinded fashion, the efficacy of 6 L of polyethylene glycol-based lavage solution (Golytely) administered on an outpatient basis in diabetic versus nondiabetic patients.
Methods: A total of 54 consecutive nondiabetic and 45 consecutive diabetic patients requiring outpatient colonoscopy underwent colonic cleansing by drinking 6 L of Golytely the evening before the procedure. The entire procedure, from rectum to cecum, was videotaped and coded for later review by the Chief of Endoscopy who was blinded to the identity and medical history of the patients. The primary outcome measure was the quality of the preparation score, numerically rated on a 14-point scale (0-13) based on the surface area of the mucosa that could be examined and the consistency of the residual stool.
Results: There was a significant difference in the quality ratings for the bowel preparations, with an overall superior preparation in the nondiabetic group (2.4+/-1.6 vs 5.4+/-3.1, p < 0.001). A total of 97% of the nondiabetic patients had a preparation rated as good or better, compared with only 62% of the diabetic patients (p < 0.001). Preparations rated as poor or futile, necessitating repeat colonoscopy, occurred in no nondiabetic but in 9% of diabetic patients (p < 0.01). Within the diabetic group, there was no significant difference in bowel preparation scores between those patients aged >70 yr and those <70 yr, those requiring and those not requiring insulin, those with Hb A1c values >8% and those with values <8%, and those with and without peripheral neuropathy.
Conclusion: We conclude that diabetic patients (irrespective of insulin use, diabetic control, or diabetic neuropathy) have a significantly poorer response to a 6-L Golytely preparation than do nondiabetic patients.