Clinical trial: 2-L polyethylene glycol-based lavage solutions for colonoscopy preparation - a randomized, single-blind study of two formulations

Background The 2-L polyethylene glycol (PEG) lavage solutions provide efficacy similar to that of standard 4-L PEG formulations in spite of the reduced volume. The comparative efficacy and tolerability of two formulations of 2-L PEG solution remain unknown. Aims To assess the efficacy, safety and tolerability of PEG + Bis compared with PEG + Asc, and to study the effect of bowel cleansing quality on adenoma detection rates. Methods Patients were randomized to receive either 2-L PEG with ascorbic acid (PEG + Asc) or 2-L PEG plus bisacodyl 10 mg (PEG + Bis). The primary endpoint was overall colon cleansing score, assessed by blinded investigators using a validated four-point scale. Secondary endpoints included adenoma detection rate, patient tolerability and compliance and adverse events. Results Fifty-two patients received PEG + Asc and 55 patients received PEG + Bis. Overall colon cleansing scores (+/- s.d.) were 1.40 +/- 0.69 and 1.75 +/- 0.70 (P < 0.003) in the PEG + Asc and PEG + Bis groups, respectively. Excellent and good ratings were recorded in 69% and 23% receiving PEG + Asc compared to 38% and 51% (P = 0.01) of patients receiving PEG + Bis. More adenomas were detected in colonoscopies performed with PEG + Asc (39%) than in those performed with PEG + Bis (20%) (P = 0.04). Patient tolerability and safety were similar with both preparations. Conclusion The use of PEG + Asc resulted in better colon cleansing and higher adenoma detection rates compared with PEG + Bis.