To compare the efficacy and safety of bowel preparation using lactulose alone versus compound polyethylene glycol electrolyte powder in high-risk populations.

High-risk individuals who were scheduled to undergo colonoscopy in the Gastroenterology Department of the Second Hospital of Tianjin Medical University from July 2023 to June 2025 were selected and divided into a lactulose group (160 cases) and a compound polyethylene glycol group (160 cases) using a random number table method. The observation indicators included the adequacy rate of bowel preparation, Boston score, colonoscope lens clarity score, time of advancing and withdrawing the scope, detection rate of polyps and adenomas, interval time to the first defecation, blood electrolyte levels, blood glucose levels, blood pressure, blood creatinine levels, plasma osmolarity levels, and adverse reactions in both groups of patients. Additionally, a questionnaire was used to investigate the proportion of patients who were willing to use the bowel cleansing regimen again. T test was used to compared the measurement data, Chi-square test was used to compared the count data.

147 patients in the lactulose group and 145 patients in the compound polyethylene glycol group completed the study. The adequacy rate of bowel preparation, Boston score, and colonoscopy lens clarity score in the lactulose group were 72.8% (107/147), (6.67±1.24) points, and (1.28±0.33) points, respectively, while those in the polyethylene glycol compound group were 57.2% (83/145), (6.31±1.20) points, and (1.41±0.37) points, respectively. The differences were statistically significant (χ²=2.772, t=2.523, 2.521; P < 0.05 or P < 0.01). The detection rates of polyps and adenomas in the lactulose group were 51.7% (76/147) and 40.1% (59/147), respectively, while those in the compound polyethylene glycol group were 39.3% (57/145) and 28.3% (41/145), respectively. The differences were statistically significant (χ²=2.119, 2.126; P < 0.05). The mean time to the first defecation in the lactulose group was (1.16±0.44) hours, while that in the compound polyethylene glycol group was (1.44±0.97) hours, with a statistically significant difference (t=3.167, P < 0.01). The total incidence of adverse reactions after bowel cleansing and the proportion of patients willing to use the medication again in the lactulose group were 21.1% (31/147) and 95.2% (140/147), respectively, while those in the compound polyethylene glycol group were 46.9% (68/145) and 82.8% (120/145), respectively. The differences were statistically significant (χ²=4.564, 11.958; P < 0.01).

For high-risk populations, using lactulose alone for bowel preparation exhibits better cleansing efficacy and a higher adenoma detection rate compared to compound polyethylene glycol, along with a lower incidence of adverse reactions and minimal impact on blood circulation.