Endoscopy 2010; 42(8): 633-638
DOI: 10.1055/s-0029-1244236
Original article

© Georg Thieme Verlag KG Stuttgart · New York

A randomized single-blind trial of standard diet versus fiber-free diet with polyethylene glycol electrolyte solution for colonoscopy preparation

A.  M.  Soweid1 , A.  A.  Kobeissy1 , F.  R.  Jamali2 , M.  El-Tarchichi1 , A.  Skoury1 , H.  Abdul-Baki1 , L.  El-Zahabi1 , A.  El-Sayyed1 , K.  A.  Barada1 , A.  I.  Sharara1 , F.  Mourad1 , A.  Arabi1
  • 1Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon
  • 2Department of Surgery, American University of Beirut Medical Center, Beirut, Lebanon
Further Information

Publication History

submitted 19 November 2009

accepted after revision 28 April 2010

Publication Date:
09 July 2010 (online)

Background and study aims: Colonoscopy preparation usually involves the intake of large volumes of polyethylene glycol electrolyte solution (PEG-ES) in combination with a clear-liquid diet (CLD). Liberalization of the diet might enhance the tolerance to PEG-ES without compromising the quality of the preparation. The primary aims of this study were to evaluate the efficacy and tolerability of PEG-ES given with a CLD compared with a fiber-free diet (FFD) for colonoscopy preparation. The incidence of adverse events among patients in the two diet groups was also assessed as a secondary outcome.

Methods: This was a single-center randomized, prospective, single-blind study. A total of 200 patients undergoing colonoscopy were randomized to either CLD or FFD in addition to PEG-ES.

Results: Patients in the FFD group were able to drink more PEG-ES (mean ± SD, 3.9 ± 0.3 L) compared with those in the CLD group (3.3 ± 0.7 L) (P < 0.01). The quality of the preparation was significantly better in the FFD group, with more patients having satisfactory preparations than those in the CLD group (81.4 % vs. 52.0 %; P < 0.001). Tolerance to the preparation was higher in the FFD group compared with the CLD group, with significantly more patients adhering to the FFD regimen (P < 0.001). There were more adverse events experienced in the CLD group, with odds ratios of 1.9 for nausea (95 % confidence interval [CI] 1.0 – 3.6), 3.8 for vomiting (95 % CI 1.3 – 11.3), and 3.0 for headache (95 % CI 1.5 – 5.9).

Conclusion: FFD given with PEG-ES on the day before colonoscopy is a more effective regimen than the standard CLD regimen, and is better tolerated by patients.


A. Soweid, MD 

American University of Beirut Medical Center

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Email: as25@aub.edu.lb