Development And Validation Of A Prediction Model For Inadequate Bowel Preparation For Colonoscopy In Elderly Patients

Objective:To investigate and analyze the current status and related risk factors of inadequate bowel preparation in elderly patients undergoing colonoscopy,construct a prediction model for inadequate bowel preparation in elderly patients,and provide the evidence for clinical assessment of the risk of inadequate bowel preparation in elderly patients undergoing colonoscopy and the formulation of targeted intervention measures.Methods:The convenience sampling method was adopted to select elderly patients undergoing colonoscopy in a tertiary grade A hospital in Taiyuan from May 2021 to October 2021 as the research objects.The self-compiled bowel preparation questionnaire of the elderly patients undergoing colonoscopy was used to collect the general data,disease-related data and examination-related data of the patients.Random number table method was used to divide the research objects into development group and validation group in a ratio of 2:1.The patients in the development group were divided into the successful group and the failed group according to the quality of bowel preparation,theχ~2 test was used for comparison between the two groups.The variables with P<0.100 were included in the Logistic regression for multivariate analysis to determine independent risk factors for inadequate bowel preparation in elderly patients.We used the regression coefficient of each risk factor to assign the risk score and established a prediction model of inadequate bowel preparation in elderly patients undergoing colonoscopy.The validation group data were used to verify the model internally.Hosmer-Lemeshowχ~2 test and the area under the ROC curve were used to evaluate the predictive effect of the model.Results:1.A total of 610 elderly patients undergoing colonoscopy were included,of which 174patients(28.5%)were inadequate bowel preparation.In the development group,there were406 cases,112 cases(27.6%)were inadequate bowel preparation.In the validation group,there were 204 cases,62 cases(30.4%)were inadequate bowel preparation.All variables of the patients in the development group and the validation group were analyzed,and the results showed that there were no statistical differences in the general data,disease-related data and examination-related data between the two groups(P>0.05).2.Univariate analysis in the development group showed that there were statistically significant differences among patients with age,BMI,walking function,constipation,diabetes,history of colorectal surgery,history of other abdominal/pelvic surgery,and the first experience of colonoscopy(P<0.100).Logistic regression analysis showed that age>65years(OR=1.856,95%CI:1.153～2.988,P=0.011),BMI≥24(OR=1.844,95%CI:1.146～2.967,P=0.012),constipation(OR=2.763,95%CI:1.645～4.641,P<0.001),diabetes(OR=2.126,95%CI:1.236～3.659,P=0.006),history of colorectal surgery(OR=4.663,95%CI:2.004～10.850,P<0.001),and the first experience of colonoscopy(OR=3.079,95%CI:1.724～5.500,P<0.001)were independent risk factors for inadequate bowel preparation in elderly patients.3.The influencing factors and corresponding scores of the prediction model of inadequate bowel preparation for elderly patients undergoing colonoscopy were:age>65years(2 points),BMI≥24(2 points),constipation(3 points),diabetes(2 points),history of colorectal surgery(5 points),and the first experience of colonoscopy(4 points).The total score of the model was 0 points to 18 points,with a score≥8 points classified as high-risk group.In the development group,the results showed that Hosmer-Lemeshowχ~2=8.969,P=0.255;the area under ROC curve was 0.717(95%CI:0.660～0.773,P<0.001),sensitivity and specificity were 50.89%and 79.59%.In the validation group,the results showed that Hosmer-Lemeshowχ~2=4.188,P=0.840;the area under the ROC curve was0.720(95%CI:0.645～0.796,P<0.001),sensitivity and specificity were 48.38%and81.69%,and the accuracy was 71.57%.Conclusion:In this study,age>65 years,BMI≥24,constipation,diabetes,history of colorectal surgery and the first experience of colonoscopy were independent risk factors for inadequate bowel preparation in elderly patients.The prediction model constructed in this study has good predictive effect and can be used to assess the risk of inadequate bowel preparation in elderly patients undergoing colonoscopy before colonoscopy,providing an effective and simple risk assessment tool for clinical.