Study Of Risk Factors And Prediction Models For Critical Colonoscopy Quality Indicators

【Background】Previous studies showed lower incidence rate of colorectal cancers and cancer induced morality rate are associated with high quality colonoscopy examination.therefore,high-quality screening and follow-up play an critical role on diagnostic and therapeutic colonoscopy.Updated guidelines from worldwide demonstrated that several colonoscopy indicators,including colonrectal adenoma detection rate(ADR),cecal intubation rate,withdrawal time and bowel preparation quality.Moreover,as abdominal discomfort and pain are most common complications during colonoscopy,this parameter can also be regarded as one quality indicator.In previous studies,issues about ADR and withdrawal time are more to be investigated.However,there are limited evidence about difficulty and discomfort during procedure.High-quality bowel preparation is important for colonoscopy manipulation and inspect of lesions.However,30%patients had poor bowel preparation in practice.Many patient-related factors(e.g.old age,constipation use of anti-tricyclic antidepressants)and many procedure-related factors(e.g.poor diet restriction and prolonged interval between preparation and colonoscopy)for inadequate BP had been identified in previous studies.However,there are no ideal prediction models for inadequate bowel preparation.Successful cecal intubation is an essential foundation of entire examination of colorectal lesions.However,about 5%colonoscopies could not reach into cecum.Furthermore,more lesions were missed in clinical practice.Besides,insertion time≥10mins or successful reach into cecum only after≥2 intubation were considered as difficult colonoscopy.The above condition brought more discomfort for patients and more frustration for endoscopists,which may lead to higher missed rate of lesions.Therefore,accurate prediction for difficult colonoscopy would offer a basis for individual intervention for special patients.Compared with sedated colonoscopy,Advantages of unsedated colonoscopy included simple evaluation,less medical practitioners involved,speedy recover after colonoscopy and less cost.However,discomfort and pain during colonoscopy imposed negative impact on unsedated colonoscopy.10-30%patients underwent obvious discomfort during examination.The identification of risk factors for discomfort before procedure is important for increased acceptability of unsedated colonoscopy,promoted patients’experience and decreased medical cost.【Objective】The aim of this study is to investigate possible risk factors and prediction models for those colonoscopy indicators,which may lay the foundations for individual intervention and the improvement of colonoscopy diagnosis and treatment.The purposes of this study are shown as follows.1.To investigate patient and procedure-related risk factors for inadequate quality of bowel preparation,establish prediction models,and validate the new-built models in the other cohort.2.To investigate related risk factors of difficult colonoscopy,establish the related prediction model,and validate the discrimination among the models.3.To evaluate the distribution of discomfort or pain in patients undergoing unsedated colonoscopy,identify possible risk factors,verify the prediction models,and explore the relationship between those new models with some indicators of colonoscopy.【Method】1.The patient and procedure related data of patients in the First Affiliated Hospital of Air Force Military Medical University were prospectively collect.The significant predictive risk factors for inadequate BP defined by segmental Boston Bowel Preparation Scale(BBPS)score<2 were generated by logistic regression.The variables of P<0.05 in univariate analysis of the training cohort were included in the multivariate logistic regression analysis.The secondary endpoint included PDR.The risk factor for inadequate BP was assigned as a score of 1 to form a predictive model and establish the bowel preparation score(BPS).The cut-off value of BPS was determined by ROC curve analysis,and the influence of different BPS scores on the inadequate bowel preparation and polyp detection rate(PDR)were evaluated.Further validation was performed in the validation cohort of the second people’s Hospital of Shaanxi Province.2.Patients undergoing colonoscopy in the First Affiliated Hospital of Air Force Military Medical University were enrolled.Some data,including baseline characteristics and procedure-related information,were prospectively collected.The primary endpoint was difficult colonoscopy,which was defined as the case that inserted colonoscopy did not reach the cecum when intubation time is≥10 minutes.Secondary endpoints included the maximum pain score,abdominal compression and position adjustment.Log rank test was used to investigate the risk factors related to insertion time.Cox regression analysis was used to determine independent high risk factors related to colonoscopy difficulty.The covariates with P value<0.1 in univariate analysis were included in multivariate analysis.According to the regression coefficient of the significant variables in multivariate regression analysis,the difficult colonoscopy score(DCS)was established.Moreover,the influence of different DCS scores on the insertion time was analyzed.The cutoff value of DCS was determined by the receiver operating characteristic curve analysis of the subjects who completed the cecum intubation within 10 minutes,and the influence of different DCS scores on the related variables of difficult colonoscopy was also evaluated.3.The baseline characteristics and related examination data of patients undergoing unsedated colonoscopy in the First Affiliated Hospital of Air Force Military Medical University were prospectively collected.Univariate and multivariate logistic regression analysis were performed to identify independent risk factors of pain.The primary endpoint was painful colonoscopy,which was defined as the occurrence of pain during examination.Other secondary endpoints included insertion time,successful insertion rate,abdominal compression and body position adjustment.Based on the regression coefficient of each significant variable in multivariate regression analysis,the insertion discomfort score(IDS)was established.The cut-off values of IDS were determined by ROC curve analysis of subjects with moderate or severe pain,and the effects of different IDS scores on the occurrence of pain colonoscopy and related variables during colonoscopy were also evaluated.Furthermore,patients were enrolled into the validation cohort from the second people’s Hospital of Shaanxi Province.IDS model was verified in the population who underwent screening and surveilence colonoscopy.【Results】Study on the influencing factors of bowel preparation1.In the trial cohort,we assessed the impact of patient-related and colonoscopy-related factors on the outcome of bowel preparation.Multivariate logistic regression analysis showed that constipation,improper dietary restriction,incorrect laxative duration,and stool frequency<8 times were significantly associated with IBP.In order to facilitate the prediction of bowel preparation quality,a score of 1 was assigned to each influencing factor related to IBP to form a prediction model.Therefore,Bowel preparation score(BPS)=1×C(1 point for constipation,0 point for no constipation)+1×D(1 point for improper diet control,0 point for proper diet control)+1×S(1 point for incorrect start time,0 point for correct start time)+1×F(stool frequency<8 times 1point,stool frequency≥8 times 0 point).2.According to BPS,patients were divided into low risk group(BPS≤1)and high risk group(BPS>1).Next,we calculated and validated BPS in both the trial and validation groups.The sensitivity,specificity,positive predictive value and negative predictive value of BPS>1 were 84.1%,59.1%,35.3%,93.3%and 85.7%,50.2%,33.9%,92.2%,respectively.The results obtained in the trial group can be confirmed in validation group.BPS>1 patients tended to be underprepared and this was consistent across all subgroups in both cohort groups.3.PDR in the high-risk group was often lower in the two groups.This was consistent in the trial cohort(22.0%vs.30.6%,P=0.088)and the validation cohort(22.6%vs.32.8%,P=0.047).Predictive model of difficult colonoscopy1.Risk factors affecting difficult colonoscopy:A total of 1253 patients who received colonoscopy were screened,of whom 616 patients met the inclusion criteria.The average age of the patients was about 50 years old,about half of them were female,and about 80%were outpatients.The success cecal intubation rate was 98.9%(609/616),and the average insertion time was 7.4±5.2min.Log-rank analysis found that age,gender,colonoscopist experience,BMI,sleep quality,and time to appointment were related to the length of colonoscopy intubation.Multivariate analysis showed that colonoscopies performed by primary colonoscopists(HR 1.29;95%CI,1.08-1.54;P=0.004),average or poor sleep quality(HR 1.33;95%CI,1.04-1.72;P=0.026),BMI<Kg/m~2(HR 1.59;95%CI,1.23-2.07;P=0.001),≥65 years old(HR 1.29;95%CI,1.03-1.62;P=0.027)was an independent risk factor affecting insertion time.2.The established difficult colonoscopy prediction model DCS:1×A(1≥65 years old,0<65 years old)+2×B(2 BMI<18.5 Kg/m~2,0≥18.5 Kg/m~2)+1×C(1 refers to the operation of senior endoscopist;the primary level is 0)+1×S(1 refers to average or poor sleep quality;0 refers to good sleep quality).It was found that with the increase of the score,insertion time lengthened significantly.According to the ROC curve,patients were divided into low-risk(DCS≤1)and high-risk(DCS>1)patients.Compared with low-risk patients,high-risk patients had higher rates of difficult colonoscopy,more abdominal compression,and more frequent postural changes.Subgroup analysis showed that DCS score may be applicable to all different subgroups of colonoscopy patients(except inpatients).Study of patient discomfort/pain1.We evaluated pain-related factors during unsedated colonoscopy.Multivariate logistic regression analysis corrected for constipation and BMI<Kg/m~2Preoperative expected pain was an independent risk factor for colonoscopy pain:constipation(OR2.45,95%CI:1.25-4.80),BMI<Kg/m~2(OR 2.18,95%CI:1.09-4.37),preoperative expected moderate to severe pain(OR 2.06,95%CI:1.12-3.79);The prediction model was established by assigning 1 point to each of the three influencing risk factors.Colonoscopy score of insertion discomfort(IDS)=1×B(1 point to BMI<18.5 Kg/m~2),≥18.5 Kg/m~2 to 0)+1×C(1 point with constipation,no 0 point)+1×E(1 point with expected moderate to severe preoperative pain,0 point with expected no or mild pain).2.In both the trial and validation groups,high-risk patients with IDS≥1 had longer insertion times,lower cecal intubation rate,and more abdominal compression and postural changes.3.With the exception of the majority of diagnoses,IDS scores were also applicable in both screening or surveillance patients.With the increase of IDS,the rate of abdominal pain on examination also increased,and the high-risk group also required more abdominal compression and position changes.【Conclusion】By prospective,multicenter cohort study we discovered the influence of difficult colonoscopy,discomfort or pain in patients,bowel preparation for colonoscopy quality evaluation index of multiple independent risk factors,and then establish and verify the BPS,DCS,and IDS prediction model.The model can be effectively used to distinguish and discriminate colonoscopy quality and further enhance the overall quality of colonoscopy.