To develop a nomogram to identify patients at risk for inadequate bowel preparation so that these patients may benefit from an intensive bowel cleansing regimen.

The demographic data and clinical characteristics of 373 patients who received fractional dose intestinal preparation regimen at the Center of Digestive Endoscopy, Weihai Municipal Hospital Affiliated to Shandong University from July 2023 to September 2023 were retrospectively collected. And organize the data into a queue.We first divided the cohort into an adequate bowel preparation group and an inadequate bowel preparation group and compared the clinical data of the two groups. Then we randomly selected 80% of the queues as training queues to build the nomogram prediction model, and 20% of the queues as verification queues to verify and evaluate the differentiation and accuracy of the prediction model.

A total of 298 cases of colonoscopy were included in the development cohort. Independent risk factors included in the prediction model were diabetes (P=0.0251), constipation (P=0.0013), history of intestinal underpreparation (P=0.0431), postoperative colorectal surgery (P<0.0001), no diet management (P=0.0254), and ASA grade≥Ⅲ(P=0.0129).The nomogram obtained in this study has good discriminative ability, and the area under the curve of the development cohort is 0.7455, and the area under the curve of the verification cohort is 0.7709.The C-index of the nomogram prediction model is 0.746.The correction curve approaches the ideal curve.

The nomogram has good predictive power and can visualize the risk of inadequate bowel preparation in patients preparing for colonoscopy and is easy to use.