A retrospective comparison of the efficacy of sennoside A + B calcium solutions and polyethylene glycol solutions for bowel preparation prior colonoscopy

Background and Aim: Colonoscopy is a widely used method for diagnosing colorectal diseases. Its diagnostic accuracy largely depends on the quality of bowel preparation. Two commonly used bowel cleansing agents are sennoside A + B calcium and polyethylene glycol solutions. This study aims to compare the effectiveness of these two agents using different bowel preparation scoring systems. Materials and Method: Colonoscopies performed by a single endoscopist at a tertiary center between February 2024 and April 2025 were retrospectively evaluated. Patients received either polyethylene glycol or sennoside A + B calcium solutions for bowel preparation, based on informed patient preference. Bowel cleansing quality was assessed segmentally using the Boston bowel preparation scale, the Ottawa bowel preparation scale, and the Chicago bowel preparation scale. Results: A total of 114 patients were included in the study. The polyethylene glycol group (n = 53) achieved significantly higher scores on the Boston bowel preparation scale and the Chicago bowel preparation scale, and lower (better) scores on the Ottawa bowel preparation scale, indicating superior bowel cleansing quality compared to the sennoside group (n = 61). A strong negative correlation was observed between the Boston and Ottawa bowel preparation scales, while a strong positive correlation was found between the Boston and Chicago bowel preparation scales. The Ottawa and Chicago bowel preparation scales also demonstrated a strong negative correlation. No statistically significant correlations were found between the number of previous colonoscopies or the time since the last procedure and any of the three bowel preparation scales. Conclusion: This study demonstrated that polyethylene glycol solutions provide significantly better bowel cleansing quality compared to sennoside A + B calcium, as evaluated using three strongly correlated bowel preparation scales. The findings suggest that lower body mass index and previous colonoscopy experience may be associated with improved bowel preparation, possibly due to better patient adherence. While both agents are commonly used in clinical practice, polyethylene glycol solutions may be the preferred option, especially in patients who have undergone prior colonoscopy with inadequate bowel cleansing.