Predictive factors for inadequate colon preparation before colonoscopy

Incidence and predicting factors of inadequate bowel preparation for colonoscopy: A cross-sectional study

Background and Aim

Adequate bowel preparation is necessary for optimal colonoscopy. Inadequate bowel preparation results in increased costs and imprecise colonoscopy results. This study aims to determine the incidence and risk factors of inadequate bowel preparation.

Methods

In this study, 604 consecutive patients were observed prospectively who underwent colonoscopy examination. The patient's clinical and demographic data were obtained on the day of the procedure. Bowel preparation was evaluated by Boston Bowel Preparation Scale (BBPS) and was divided into two groups; adequate and inadequate. Univariate and multivariate analyses were performed.

Results

Inadequate bowel preparation incidence was 17.9%. In the univariate analysis, education level (P value = 0.009), body mass index (P value = 0.03), admission type (P value = 0.038), previous history of colonoscopy (P value = 0.03), color and consistency of the last feces (P value = 0.03), diabetes (P value = 0.004), and smoking (P value = 0.03) were significantly related with the incidence of inadequate bowel preparation. While ischemic heart disease (IHD) decreased the level of inadequate bowel preparation (P value = 0.047). Multivariate analysis showed that diabetes mellitus (odds ratio [OR] = 2.18), smoking (OR = 2.10), inpatient status of admission type (OR = 3.32), last stool that was non-watery (OR = 1.60), and ischemic heart disease (OR = 0.032) were independent factors associated with inadequate bowel preparation.

Conclusion

Diabetic patients, smokers, inpatients and who defecated a non-watery and colory stool as the last defecation are at risk of inadequate bowel preparation and need more potent regimens. It is important to inform patients about preventable factors that affect bowel preparation to improve their preparation outcomes.

Superiority of a preparation-related model for predicting inadequate bowel preparation in patients undergoing colonoscopy: A multicenter prospective study

BACKGROUND AND AIM

Three models based on patient-related factors have been developed to predict inadequate bowel preparation (BP). However, the performance of the models seems suboptimal. This study aimed to develop a novel preparation-related model and compare it with the available patient-related models.

METHODS

Patients receiving standard BP were prospectively enrolled from five endoscopic centers. Patient-related and preparation-related factors for inadequate BP (defined by segmental Boston Bowel Preparation Scale score < 2) were identified by logistic regression. A preparation-related model was derived and internally validated in 906 patients. The comparisons of models were assessed by discrimination and calibration. The preparation-related model was also externally validated.

RESULTS

Several patient-related factors (male and American Society of Anesthesiologists Physical Status Classification System score ≥ 3) and preparation-related factors (drinking-to-stool interval ≥ 3 h, preparation-to-colonoscopy interval ≥ 6 h, and poor rectal effluent) were found to be independently associated with inadequate BP (all P < 0.05). C-statistics was 0.81 for the preparation-related model in the training cohort (n = 604), significantly higher than three available patient-based models (0.58-0.61). Similar results were observed in the validation cohort (n = 302). Calibration curves showed close agreement in the preparation-related model (R²  = 0.315 in the training cohort and 0.279 in the validation cohort). The preparation-related model was externally validated in another 606 patients with C-index of 0.80.

CONCLUSIONS

A new preparation-related model (consisting of drinking-to-stool interval ≥ 3 h, preparation-to-colonoscopy interval ≥ 6 h, and poor last rectal effluent) was developed and performed better than three available patient-related models. This easy-to-use model may be a useful decision-support tool on individualized plans in patients undergoing BP.

Regression and Random Forest Machine Learning Have Limited Performance in Predicting Bowel Preparation in Veteran Population

BACKGROUND

Inadequate bowel preparation undermines the quality of colonoscopy, but patients likely to be affected are difficult to identify beforehand.

AIMS

This study aimed to develop, validate, and compare prediction models for bowel preparation inadequacy using conventional logistic regression (LR) and random forest machine learning (RFML).

METHODS

We created a retrospective cohort of patients who underwent outpatient colonoscopy at a single VA medical center between January 2012 and October 2015. Candidate predictor variables were chosen after a literature review. We extracted all available predictor variables from the electronic medical record, and bowel preparation from the endoscopy database. The data were split into 70% training and 30% validation sets. Multivariable LR and RFML were used to predict preparation inadequacy as a dichotomous outcome.

RESULTS

The cohort included 6,885 Veterans, of whom 964 (14%) had inadequate preparation. Using LR, the area under the receiver operating characteristic curve (AUC) for the validation cohort was 0.66 (95% CI 0.62, 0.69) and the Brier score, in which a lower score indicates better performance, was 0.11. Using RFML, the AUC for the validation cohort was 0.61 (95% CI 0.58, 0.65) and the Brier score was 0.12.

CONCLUSIONS

LR and RFML had similar performance in predicting bowel preparation, which was modest and likely insufficient for use in practice. Future research is needed to identify additional predictor variables and to test other machine learning algorithms. At present, endoscopy units should focus on universal strategies to enhance preparation adequacy.

Comparative Effectiveness of Commercial Bowel Preparations in Ambulatory Patients Presenting for Screening or Surveillance Colonoscopy

BACKGROUND

Inadequate bowel preparation (IBP) is associated with reduced adenoma detection. However, limited research has examined the impact of different commercial bowel preparations (CBPs) on IBP and adenoma detection. We aim to determine whether type of CBP used is associated with IBP or adenoma detection.

METHODS

We retrospectively evaluated outpatient, screening or surveillance colonoscopies performed in the Cleveland Clinic health system between January 2011 and June 2017. IBP was defined by the Aronchick scale. Multilevel mixed-effects logistic regression was performed to assess the association between CBP type and IBP and adenoma detection. Fixed effects were defined as demographics, comorbidities, medication use, and colonoscopy factors. Random effect of individual endoscopist was considered.

RESULTS

Of 153,639 colonoscopies, 75,874 records met inclusion criteria. Median age was 54; 50% were female; 17.7% had IBP, and adenoma detection rate was 32.6%. In adjusted analyses, compared to GoLYTELY, only NuLYTELY [OR 0.66 (95% CI 0.60, 0.72)] and SuPREP [OR 0.53 (95% CI 0.40, 0.69)] were associated with reduced IBP. Adenoma detection did not vary based on the type of bowel preparation used.

CONCLUSIONS

Among patients referred for screening or surveillance colonoscopy, choice of CBP was not associated with adenoma detection. Decisions about CBP should be based on other factors, such as tolerability, cost, or safety.

Consistency of faecal scoring using two canine faecal scoring systems

OBJECTIVE

To determine the agreement of canine faecal scoring between individuals with different levels of experience using two available faecal scoring systems.

MATERIALS AND METHODS

Naturally-voided, undisturbed bowel movements from 126 dogs were evaluated by veterinarians (n = 3) and members of the lay public (n = 126) within 15 minutes of defecation. Each participant was provided a copy of the Purina and Waltham faecal scoring charts in order to characterise the faeces. Agreement between veterinarians and lay people was assessed with kappa statistics, Bland-Altman analysis and visualised with Bland-Altman plots.

RESULTS

Variable levels of consistency were observed in assessing faecal form among individuals with varying degrees of experience. Fair to substantial agreement existed between individual veterinarians scoring the same bowel movement (kappa statistic ranging from 0.40 to 0.77 on the Purina Scale and 0.54 to 0.61 on the Waltham Scale), while the agreement scores between the veterinarian and the lay public was fair (kappa statistic of 0.38 on the Purina Scale and 0.34 on the Waltham Scale). Disagreement in faecal scores occurred more frequently with lay people versus veterinarians.

CLINICAL SIGNIFICANCE

The consistency of faecal scoring improved based on the level of experience with the highest agreement consistently noted between veterinarians. In all comparisons, there was inconsistency in faecal scoring which might have implications for veterinarians managing diarrhoeic canine patients. Further studies are needed to better investigate how faecal scoring can be optimised for use in clinical and research settings.

An Evidence-based Approach Towards Targeted Patient Education to Improve Bowel Preparation for Colonoscopy

GOALS AND BACKGROUND

Quality of bowel preparation is an important factor influencing adenoma detection. Patient education is believed to improve the quality of bowel preparation but might be resource-intensive. We aimed to (a) identify risk factors for failed bowel preparations and (b) develop and test the efficacy of a screening tool that allows to prospectively identify and target patients at increased risk.

STUDY

Part 1: 76 consecutive outpatients with poor bowel preparation were compared with 76 age-matched and gender-matched outpatients with good preparation from the same procedure lists. Sociodemographic and clinical data were obtained from centralized databases. Univariate analysis and multivariate logistic regression was used to identify risk factors for poor bowel preparation. Part 2: on the basis of results of part 1, a screening tool for prospectively identifying patients at high risk was developed, and targeted education tested.

RESULTS

We identified the use of opioids or other constipating agents and low socioeconomic status as risk factors for poor bowel preparation [odds ratio (OR)=2.88; 95% confidence interval (CI): 1.22-6.80 and OR=2.43; 95% CI: 1.25-4.72]. Diabetes, hypothyroidism, age, and gender were found to have no effect on quality. When education was provided only to patients at increased risk, the targeted approach did not negatively affect the proportion of poor preparation (OR=6.12%; 95% CI: 4.79%-7.78% vs. OR=5.73%; 95% CI: 4.61%-7.10%).

CONCLUSIONS

Poor bowel preparation is associated with specific risk factors. Identifying and specifically targeting education at patients with these risk factors appears to facilitate more efficient use of education resources in endoscopy.

Improving the Quality of Bowel Preparation: Rewarding Patients for Success or Intensive Patient Education?

INTRODUCTION AND OBJECTIVES

The quality of the bowel preparation is a critical parameter for the outcome of colonoscopies. It is well established that the bowel preparation modality (e.g., split or larger volume preparation) significantly improves the quality of the bowel preparation. Patient compliance is another important factor impacting on the quality of bowel preparations that receives relatively little research attention. We aimed to explore if intensified education or a lottery ticket as reward for good bowel preparation could improve outcomes.

METHODS

After informed consent, all patients received a standardized printed information booklet. In a randomized fashion, patients were offered (a) a lottery scratchy ticket with an opportunity to win $25,000 as "reward" for good bowel preparation, (b) an education session delivered over the phone by a trained nurse, or (c) no additional measure.

RESULTS

Overall, the quality of the bowel preparation was rated good or very good in 69.1% (95% CI 61.7-75.7%) of patients. Reward intervention did not influence the quality of bowel preparation (OR 0.42, 95% CI 0.09-1.91, p = 0.260); however, bowel preparation quality decreased in patients randomized to receive the additional education (OR 0.28, 95% CI 0.08-0.96, p = 0.042). Neither intervention significantly impacted on polyp detection rates.

CONCLUSIONS

Contrasting general beliefs, additional interventions (e.g., incentives or phone consultation) did not improve the quality of the bowel preparation. The unexpected result shows that utilizing extra resources must be balanced against real-world outcomes and may not always provide the expected result.

Effect of the High-FODMAP Diet on Bowel Preparation for Colonoscopy: A Multicenter, Prospective Cohort Study

Background

Optimal bowel preparation for colonoscopy is fundamental to a successful examination. The FODMAP diet can increase the content of intestinal water and gas, but its impact on bowel cleanliness and bubbles has not been reported. This study was therefore aimed at evaluating the effect of the FODMAP diet on the quality of bowel preparation and the adenoma detection rate (ADR).

Methods

This was a multicenter, prospective cohort study involving consecutive patients who underwent colonoscopy in two centers in China. Patients were assigned to one of two groups: high-FODMAP or nonhigh-FODMAP diet. ODMP Software was used for the identification of FODMAP diet types. The primary outcome was ADR; secondary outcomes were the quality of bowel preparation, measured by the Boston bowel preparation scale and bubble scores.

Results

There were 365 patients included. Patients in the high-FODMAP-diet group showed poor bowel cleansing efficacy: BBPS ≥ 6 in 76.8% vs. 90.3% (P < 0.01) and bubble scores of 2.42 ± 1.69 vs. 1.32 ± 1.63 (P < 0.001). The intubation time was significantly longer in the high-FODMAP-diet group (7.07 ± 5.18 vs. 5.46 ± 3.05 min; P = 0.002). The High-FODMAP diet was an independent risk predictor for inadequate bowel preparation. There were no statistically significant differences in ADR between the two dietary groups.

Conclusion

The high-FODMAP diet significantly reduced the quality of bowel preparation. We recommend the consumption of nonhigh-FODMAP diet in bowel preparation as a reference standard for dietary regimen. This method was effective, flexible, referable, and well tolerated, which could help to provide patients a valuable dietary guidance in bowel preparation.

Predictive factors for inadequate bowel preparation using low-volume polyethylene glycol (PEG) plus ascorbic acid for an outpatient colonoscopy

Low-volume polyethylene glycol (PEG) plus ascorbic acid solutions are widely used for bowel cleansing before colonoscopy. This study aimed to investigate the pre-endoscopic predictive factors for inadequate preparation in subjects receiving low-volume PEG plus ascorbic acid. A prospective study was performed at Gangnam Severance Hospital, Korea, from June 2016 to December 2016. All participants received low-volume PEG plus ascorbic acid solutions for outpatient colonoscopy. The split-dose bowel preparation was administered in subject with morning colonoscopy while same day bowel preparation was used for afternoon colonoscopy. 715 patients were enrolled (mean age 56.1 years, 54.4% male), of which 138 (19.3%) had an inadequate bowel preparation. In multivariable analysis, cirrhosis (OR 4.943, 95% CI 1.191–20.515), low (less than 70%) compliance for three-day low-residual diet (OR 2.165, 95% CI 1.333–3.515), brown liquid rectal effluent (compared with clear or semi-clear effluent) (OR 7.604, 95% CI, 1.760–32.857), and longer time interval (≥2 hours) between last defecation and colonoscopic examination (OR 1.841, 95% CI, 1.190–2.849) were found as an independent predictors for inadequate preparation. These predictive factors may be useful in guiding additional intervention to improve quality of bowel preparation.

Lifestyle Factors and Bowel Preparation for Screening Colonoscopy

Purpose

The quality of bowel preparation is a major determinant of the quality of colonoscopy. This study evaluated lifestyle factors, including usual dietary style, associated with bowel preparation.

Methods

This retrospective study evaluated 1,079 consecutive subjects who underwent complete colonoscopy from December 2012 to April 2014 at National Cancer Center of Korea. Questionnaires on bowel preparation were completed by the subjects, with the quality of bowel preparation categorized as optimal (excellent or good) or suboptimal (fair, poor or inadequate). Lifestyle factors associated with bowel preparation were analyzed.

Results

The 1,079 subjects included 680 male (63.0%) and 399 female patietns (37.0%), with a mean age of 49.6 ± 8.32 years. Bowel preparation was categorized as optimal in 657 subjects (60.9%) and as suboptimal in 422 (39.1%). Univariate analyses showed no differences between groups in lifestyle factors, such as regular exercise, alcohol intake, smoking, and dietary factor. Body mass index (BMI) > 25 kg/m² was the only factor associated with suboptimal bowel preparation on both the univariate (P = 0.007) and the multivariate (odds ratio, 1.437; 95% confidence interval, 1.104–1.871; P = 0.007) analyses.

Conclusion

Most lifestyle factors, including dietary patterns, exercise, alcohol intake and smoking, were not associated with suboptimal bowel preparation in Koreans. However, BMI > 25 kg/m² was independently associated with suboptimal bowel preparation. More intense preparation regimens before colonoscopy can be helpful in subjects with BMI > 25 kg/m².

Predictors of inadequate bowel preparation for colonoscopy: a systematic review and meta-analysis

The aim of this study was to investigate factors contributing to poor bowel preparation in patients undergoing colonoscopy procedures. We used a reproducible search strategy to identify studies, searching 10 medical databases, including PubMed, Ovid, Medline, and Cochrane Library Database for reports published between 2000 and 2016. Fully published studies, evaluating risk factors for inadequate bowel preparation, were included. Two reviewers independently scored the identified studies for methodology and abstracted pertinent data. Pooling was conducted with both fixed-effects and random-effects models; results were presented from the random effects model when heterogeneity was significant. Odds ratios (OR) estimates with 95% confidence interval were calculated. Heterogeneity was assessed by I statistics. Twenty-four studies with a total of 49 868 patients met the inclusion criteria. Age (OR: -1.20), male sex (OR: 0.85), inpatient status (OR: 0.57), diabetes mellitus (OR: 0.58), hypertension (OR: 0.58), cirrhosis (OR: 0.49), narcotic use (OR: 0.59), constipation (OR: 0.61), stroke (OR; 0.51), and tricyclic antidepressant (TCA) use (0.51), were associated with inadequate bowel preparation. In our sensitivity analysis comparing Western and Asian countries, we found that diabetes, cirrhosis, male sex, history of stroke and TCA use were stronger risk factors for inadequate bowel preparation in Western countries than in Asian countries. We also found that history of stroke, TCA use, and race were risk factors for inadequate bowel preparation in patients receiving conventional bowel preparation compared with those receiving split-dose bowel preparation. Multiple risk factors affect the quality of bowel preparation and specific risk factors can be intervened upon, in different populations, to optimize preparation.

Prospective analysis of factors associated with inadequate bowel preparation for colonoscopy in actual clinical practice

Background/Aims

Inadequate bowel preparation can result in prolonged procedure time and increased missed lesion and complication rates. This prospective study aimed to evaluate bowel preparation quality and identify the predictive factors for inadequate bowel preparation in actual clinical practice.

Methods

We included 399 patients who underwent colonoscopy between June 2015 and July 2016. Using the Aronchick bowel preparation scale, we defined a score ≤2 as adequate preparation and a score >2 as inadequate preparation.

Results

Mean patient age was 58.38±12.97 years; 60.6% were male. Indications for colonoscopy included screening (69.7%) and surveillance after polyp removal (21.3%). A split-dose regimen was prescribed to 55.4% of patients. The inadequate bowel preparation rate was 28.1%. Overall, the median time between the last bowel preparation agent dose and start of colonoscopy was 5.0 hours (range, 1.5-16.0 hours); that of the adequate group was 5.0 hours (range, 1.5-16.0 hours); and that of the inadequate group was 5 hours (range, 2-23 hours). The mean bowel preparation scale score of the ascending colon (1.94±0.25) was significantly higher than that of other colon segments. On multivariate analysis, elderly age, history of cerebrovascular disease, history of gastrectomy or appendectomy, and total preparation solution uptake <2 L were the independent predictors of inadequate bowel preparation.

Conclusions

The inadequate bowel preparation rate was 28.1%. Risk factors included elderly age and history of cerebrovascular disease or abdominal surgery. Patients with these risk factors require special care and education.

Patient Characteristics Associated With Quality of Colonoscopy Preparation: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Some features of patients are associated with inadequate bowel preparation, which reduces the effectiveness of colonoscopy examination. We performed a systematic review and meta-analysis of the association between patients' sociodemographic characteristics, health conditions, and medications with inadequate bowel preparation.

METHODS

We searched the PubMed, Scopus, and Cochrane Review databases for randomized controlled trials cohort (prospective and retrospective), case-control, and cross-sectional studies published through March 2016. We collected information on study design, study population, and bowel preparation. For each factor, we obtained the odds ratio (OR) for inadequate bowel preparation. We conducted the meta-analyses using the random-effects approach and investigated any identified heterogeneity and publication bias via graphical methods, stratification, and meta-regression.

RESULTS

We performed a meta-analysis of 67 studies, comprising 75,818 patients. The estimated pooled OR for inadequate bowel preparation was small for sociodemographic characteristics: 1.14 for age, and 1.23 for male sex (excluding studies in Asia, which had substantial heterogeneity and publication bias), and 1.49 for low education. The effect of high body mass index differed significantly in studies with mostly female patients (OR, 1.05) vs those with mostly male patients (OR, 1.30) (P = .013 for the difference). ORs for constipation and cirrhosis were heterogeneous; adjusted ORs were larger than unadjusted ORs (1.97 vs 1.29 for constipation and 3.41 vs 1.36 for cirrhosis). Diabetes (OR, 1.79), hypertension (OR, 1.25), stroke or dementia (OR, 2.09), and opioid use (OR, 1.70) were associated with inadequate bowel preparation. History of abdominal surgery (OR, 0.99) did not associate with inadequate bowel preparation. Use of tricyclic antidepressants had a larger effect on risk of inadequate bowel preparation in studies of mostly female patients (OR, 2.62) than studies of mostly male patients (OR, 1.42) (P = .085 for the difference).

CONCLUSIONS

In a systematic review and meta-analysis, we found no single patient-related factor to be solely associated with inadequate bowel preparation. Health conditions and use of some medications appear to be stronger predictors than sociodemographic characteristics.

The incidence of and risk factors for inadequate bowel preparation in elderly patients: A prospective observational study

BACKGROUND/AIM

: We conducted a prospective observational study to identify the incidence of and risk factors for inadequate bowel preparation in elderly Chinese patients.

PATIENTS AND METHODS

We enrolled 240 outpatients over 60 years of age scheduled for elective colonoscopy at our university hospital between November 2016 and April 2017. We recorded patient demographics, bowel preparation data, and clinical characteristics. Factors associated with inadequate bowel preparation were identified by multivariate logistical regression analysis.

RESULTS

The rate of inadequate bowel preparation was 34.6%. Factors associated with inadequate bowel preparation were a history of abdominal surgery (OR, 2.617; CI, 1.324-5.174; P = 0.006), chronic constipation (OR, 3.307; CI, 1.551-7.054; P = 0.002), non-compliance with dietary instructions (OR, 2.239; CI, 1.122-4.471; P = 0.022), non-compliance with polyethylene glycol (PEG) dosage (OR, 4.576; CI, 1.855-11.287; P = 0.001), walking <30 minutes during preparation (OR, 2.474; CI, 1.261-4.855; P = 0.008), interval between PEG ingestion and the onset of bowel activity (OR, 1.025; CI, 1.010-1.040; P = 0.001), and a last stool that was not clear and watery (OR, 4.191; CI, 1.529-11.485; P = 0.005).

CONCLUSION

The incidence of adequate bowel preparation in elderly patients is not optimal. Walking <30 minutes during the PEG ingestion period may be a surrogate for bowel preparation failure. Future studies should identify elderly patients at risk for poor bowel preparation and develop interventions to improve outcomes in this population.

The management of 'hard-to-prepare' colonoscopy patients

Effective bowel cleansing is crucial for high quality colonoscopy. A notable portion of patients still present with low quality bowel preparation prior to their colonoscopy, compromising the overall quality of their colonoscopy. Areas covered: This review focuses on the main strategies that can improve the cleansing quality with a special interest on those clinical conditions that have been associated with a poor bowel preparation quality, such as patients with chronic constipation, history of bowel resection, liver cirrhosis, diabetes mellitus and chronic kidney disease. The review provides a practical and evidence-based approach to help clinicians in the management of 'hard-to-prepare' patients. Expert commentary: In the past few years, the quality of colonoscopy has become a hot topic and bowel cleansing is a crucial part of it; however, the approach to patients with an increased risk of poor bowel preparation quality is still not always supported by high-quality evidence, since most of these patients are routinely excluded from the clinical studies. Trials focused on this subgroup of patients are recommended to provide tailored bowel preparation regimens and guarantee high-quality procedures.

Correlation between obesity and metabolic syndrome-related factors and cecal intubation time during colonoscopy

Purpose

To investigate which colonoscopy (CS) cases should be presided over by endoscopists in training, using factors including obesity and metabolic syndrome.

Patients and methods

Items investigated were sex, age, body mass index (BMI), waist circumference, hypertension, diabetes, hyperlipidemia, history of abdominal surgery (excluding colectomy), colon diverticulosis, prescription of antithrombotic agents, and quality of bowel preparation. Expert physicians were defined as those with at least 9 years of endoscopy experience; all other physicians were defined as being in training. In a retrospective analysis, cases in which a physician in training reached the cecum within 15 minutes without requiring the involvement of the supervising physician were defined as eligible cases over which a physician in training should preside, while other cases were defined as non-eligible.

Results

Overall, 813 CS cases were analyzed. Males (P<0.0001), cases started by an expert physician (P<0.0001), cases of no fellow physician involvement (P<0.0001), and cases with good bowel preparation (P<0.0001) had significantly shorter cecal intubation times. Of the 562 cases presided over by a physician in training, 194 were deemed eligible and 368 non-eligible. The eligible cases had a higher proportion of males (P=0.017), younger age (P=0.033), higher BMI (P=0.034), and higher rates of hypertension (P=0.001) and good bowel preparation (P=0.001). In analysis by sex, males demonstrated significantly more eligible cases among younger patients (P=0.009) and those with good bowel preparation (P=0.008), while there were significantly more eligible cases among females with hypertension (P=0.004).

Conclusion

It may be useful to select CS cases for physicians considering sex, age, BMI, hypertension, and bowel preparation.

Constipation, fiber intake and non-compliance contribute to inadequate colonoscopy bowel preparation: a prospective cohort study

OBJECTIVE

Adequate bowel preparation is important for colonoscopy. Currently available evidence on the determinants of poor bowel preparation is largely derived from studies in Western countries. We aimed to identify the risk factors for inadequate bowel preparation for colonoscopy in the Chinese population.

METHODS

In this single-center study, patients admitted to the Outpatient Department between March 2013 and December 2015 and had indications for colonoscopy were prospectively enrolled. Questionnaires were administered to the patients. Their characteristics and procedure-related parameters such as procedure time were recorded. Bowel preparation was assessed using Boston bowel preparation scale score.

RESULTS

A total of 409 patients with a mean age of 48.8 ± 12.9 years were enrolled in the study, 60.9% of whom were men. On univariate analysis, poor educational level (P = 0.020), chronic constipation (P = 0.001), taking no physical exercise after medication (P < 0.001), a high-fiber diet during the 24-h period immediately preceding the colonoscopy (P < 0.001), incomplete intake of medication (P < 0.001), the passage of yellow or dark stools before colonoscopy (P < 0.001), waiting time (P = 0.001) and stool frequency after medication (P = 0.048) were significantly associated with inadequate bowel preparation. On multivariate analysis, chronic constipation [odds ratio (OR) 2.05, 95% confidence interval (CI) 1.31-3.23, P = 0.002], incomplete intake of the medication (OR 2.77, 95% CI 1.47-5.21, P = 0.002) and a high-fiber diet within 24 h before colonoscopy (OR 2.15, 95% CI 1.40-3.28, P < 0.001) were independent risk factors for inadequate bowel preparation.

CONCLUSIONS

Chronic constipation, poor compliance with treatment and high-fiber diet were predictors of poor bowel preparation. Patients with these risk factors require more effective strategies for bowel preparation.