Hospitalization compared to the ambulatory setting is associated to an almost twofold higher risk of failed bowel preparation before colonoscopy, while the rate of inpatients with adequately prepared colon does not exceed 50%, as they are usually of advanced age, debilitated, and suffering from comorbidities that either prevent successful ingestion of bowel prep or affect patients’ comprehension and compliance with the regimen’s instructions [
This review’s protocol has been registered at the International Prospective Register of Systematic Reviews (PROSPERO) under the registration number
Eligibility criteria were a priori delineated using the PICO statement as follows; P: inpatients undergoing colonoscopy for any indication; I: any type of intervention aiming to improve the quality of inpatient bowel preparation regardless of baseline disease or comorbidities; C: patients without intervention; and O: preparation’s adequacy rate. Any type of trial published as full text in English language was included, while pediatric studies; meta-analyses or systematic reviews, editorials, case reports, narrative reviews, and conference abstracts; studies that did not detail patient information; and duplicate publications were excluded.
A systematic computer-aided literature search of MEDLINE, Cochrane Library (Cochrane Central Register of Controlled Trials), and Google Scholar databases was performed for consistent trials. The search was initially performed on the 22nd of July 2017 and repeated on the 9th of June 2018—the full electronic search strategy is available in Supplementary Material
All articles retrieved from the search were screened independently by two reviewers (PG, GT). In case of uncertainty, disagreement was resolved by consensus. Titles and abstracts of all results were initially reviewed; thereafter, the full text of eligible studies was obtained and independently assessed for eligibility.
Data were extracted from eligible peer-reviewed articles by two investigators (PG, GT), independently using standardized extraction forms. Discrepancies regarding data extraction were also resolved by consensus.
The following data were extracted from included studies: country of study origin, number of patients enrolled and their mean age, study design and setting (year, location), and number of centers. The number of patients receiving or not intervention—defined as any measure aiming to improve bowel preparation quality, including verbal or written instructions to patients, enhanced educational measures to attending healthcare professionals or other ancillary medical providers, modifications in bowel preparation regimens (qualitative and/or quantitative), and other miscellaneous measures (not classified in previous categories) before colonoscopy—was extracted. Consequently, the number of patients with adequate bowel preparation that either received or not any intervention was extracted. For the purpose of our study, bowel preparation quality was dichotomized in two groups: adequate and inadequate. Bowel preparation was considered inadequate when it scored a total of the Boston Bowel Preparation Scale (BBPS)
Primary aim was to investigate interventions applied to inpatients undergoing colonoscopy aiming to improve colon preparation and determine their effect on the preparation’s adequacy rate. Acceptance of preparation strategies, percentage of preparation received, willingness to repeat the examination, adverse events, repeat colon examinations, and duration of hospital stay comprised the secondary aims of this review.
Extracted data were analyzed using the statistical software Review Manager (RevMan 5.3.5, Copenhagen, Denmark, the Nordic Cochrane Centre, the Cochrane Collaboration, 2014). Overall preparation adequacy rate and all secondary endpoints were calculated using generic inverse variance analysis, and they are presented as percentage with respective 95% confidence intervals (CI). For bowel preparation adequacy comparisons, odds ratios (ORs) and their 95% CIs were calculated. All outcomes were further compared using the random effects model (DerSimonian and Laird method). Heterogeneity among studies was measured using the
To assess the quality and the risk of bias of the included randomized and nonrandomized studies, we used the Cochrane collaboration tool [
The initial search generated 119 citations. After duplicate removal, 75 articles were primarily assessed by title and abstract review. Five more studies were identified through manual reference search. Finally, 34 relevant appearing results were retrieved for further assessment. Among these, 17 were excluded for various reasons, leaving 17 eligible trials to be included [
Flowchart of literature search and study selection.
Table
Summary of included studies.
Author, year | Country | Study design | Patients enrolled, |
Age (mean), intervention vs. no intervention | Intervention | Type of preparation regimen used (only for studies evaluating educational interventions) | Scale assessing bowel preparation quality |
Patients achieving adequate preparation in the intervention group, |
Patients achieving adequate preparation without intervention, |
---|---|---|---|---|---|---|---|---|---|
Chorev, 2006 |
Israel | Prospective observational, single center | 209 | 68.5 | Physician and nurse educational program (lectures and instruction on preparation); oral, written instructions provided to all patients | Pts in both cohorts received >75 years or with moderate to severe heart or kidney failure were given PEG, 3 L, the evening before. All others were given sodium phosphate, 2 bottles of 45 mL each, to be taken with 12 glasses of tap water. Time elapsing between last sip of purgative and colonoscopy is NA | Adapted quality rating scale | 72/105 | 72/104 |
Rosenfeld, 2010 | Canada | Prospective observational, endoscopist blinded, single center (first 8 weeks assigned to intervention, the following 8 weeks to conventional) | 38 | 65.1 vs. 67.9 | Patient education (instruction group provided with 5 min verbal and written instructions prior to colonoscopy vs. no instruction) | Pts in both cohorts received 4 L of PEG bowel preparation with a clear liquid diet on the day before colonoscopy. Time elapsing between last sip of purgative and colonoscopy is NA | Adapted quality rating scale | 14/16 | 7/22 |
Lee, 2015 |
South Korea | Prospective, double blind nonrandomized controlled, single center | 205 | 64 vs. 63 | Education for ward nurses (educational leaflet and lecture vs. no education) | Pts received low-residue diet 2 days before colonoscopy; on the day before colonoscopy, pts were provided a soft diet for dinner before 6 pm and, after that time, only clear water. 2 L of PEG plus ascorbic acid was ingested—250 mL every 10 minutes. For colonoscopies performed in the morning, a split-dose bowel preparation (half-dose of purgative at 8 : 00 pm on the day before the procedure and the remaining 1 L on the morning of the day of the procedure). For afternoon colonoscopies, a full dose (2 l) of PEG plu Asc between 6 : 00 and 8 : 00 am on the day of the procedure. All colonoscopies were performed between 2 and 8 hours after the purgative intake was complete | OBPS | 71/103 | 42/102 |
Chambers, 2016 | USA | Retrospective, single center | 38 | NA | Patient and nurse education (preprocedure education) | All patients received half of the 6 L preparation and a bisacodyl pill | Adapted quality rating scale | 20/26 | 4/12 |
Ergen, 2016 | USA | Prospective, randomized, single blind, controlled trial, single center | 85 | 57 vs. 58 | Patients given an educational booklet before colonoscopy | All pts received a standard preparation: clear liquid diet the day prior to the day of the procedure followed by split-dose PEG. Patients are instructed to consume 2 L between 6 pm and 8 pm the night prior to colonoscopy and 2 L between 5 am and 7 am on the day of colonoscopy | BBPS | 28/45 | 14/40 |
Shah-Khan, 2017 | USA | Prospective nonrandomized, single center | 199 | NR | Multiphase intervention program involving physicians and nursing staff education, implementation of electronic order set, and patient education | NA | Adapted quality rating scale | 99/103 | 77/96 |
Seinelä, 2003 |
Finland | Prospective, randomized, endoscopist blinded, single center | 72 | 84 | NaP vs. 4 lit PEG standard dosing | Adapted quality rating scale | 30/37 | 27/35 | |
Reilly, 2004 | USA | Retrospective, cohort, single center | 101 | NA | 4 lit PEG vs. 6 lit PEG | Adapted quality rating scale | 17/38 | 25/48 | |
Müller, 2007 | Brazil | Prospective, randomized, single center | 80 | 62.4 vs. 60.6 | Mannitol-based preparation regimen vs. sodium picosulfate-based regimen | Chilton Scale | 26/40 | 31/40 | |
Ell, 2008 |
Germany | Prospective, randomized, single blinded, multicenter | 308 | 58 vs. 59.6 | 2 lit PEG plus ascorbic vs. 4 lit PEG solution | Adapted quality rating scale | 136/153 | 147/155 | |
Kotwal, 2014 | USA | Prospective, randomized, endoscopist blinded, single center | 103 | 52.8 vs. 57.4 | Morning only preparation (4 lit PEG between 5-9 am on the day of colonoscopy vs. split-dose PEG 2 lit - 2 lit (noninferiority study) | OBPS | 16/51 | 15/52 | |
Yang, 2015 | USA | Prospective observational, multiphase, single center | 100 | 63.2 vs. 63.7 | Nurse education and electronic order set and split-dose preparation vs. standard full-dose 4 lit PEG | BBPS | 50/54 | 31/46 | |
Tae, 2015 | Korea | Prospective, randomized, controlled, single center | 62 | 56.8 vs. 52.4 | Low-volume 2 lit PEG containing ascorbic vs. 2 lit PEG plus 20 mg bisacodyl | OBPS | 30/31 | 31/31 | |
Song, 2017 |
USA | Retrospective, case series | 53 | 64.1 | Multiday preparation regimen | BBPS or Aronchick Scale |
47/53 | NA | |
Yadlapati, 2017 | USA | Pragmatic, two-cohort-quasi-experimental study; postintervention cohort prospectively built; prep-intervention cohort: historic data | 879 | 58.2 vs. 57.1 | Implementation of split-dose PEG bowel preparation algorithm combined with an electronic dataset vs. single-dose 4 L PEG solution the evening before inpatient colonoscopy | BBPS or Aronchick Scale |
381/445 | 223/534 | |
Pontone, 2018 | Italy | Prospective, randomized, controlled single-center, pilot study | 44 | 64 vs. 63 | Same-day 1 L PEG bowel preparation on the morning of the colonoscopy vs. split-dose 4 L PEG (3 L the evening before and 1 L in the morning of the day of colonoscopy) | BBPS | 14/22 | 12/22 | |
Barclay, 2013 |
USA | Prospective, randomized, controlled, single center | 82 | 73 vs. 73.5 | EGD-assisted bowel prep (2 lit PEG administered endoscopically into distal duodenum plus 1 L PEG orally the following day) vs. split-dose PEG preparation (2 lit PEG orally the evening prior and 1 lit PEG orally the following day) | OBPS | 30/42 | 15/40 |
NA: not applicable; BBPS: Boston Bowel Preparation Scale; OBPS: Ottawa Bowel Preparation Scale; PEG: polyethylene glycol; NaP: sodium phosphate; EGD: esophagogastroduodenoscopy;
Figure
Risk of bias of included randomized controlled trials.
Overall, adequate colon cleansing was achieved in 67% (60-75%) patients (heterogeneity:
Forrest plot of studies assessing inpatients’ adequacy of bowel preparation.
In the 10 studies [
No statistically significant difference among the three groups of interventions was found (Figure
There was one RCT [
Overall, 774 patients were included in the aforementioned studies [
Forrest plot of studies assessing the effect of educational intervention on bowel preparation quality of (a) overall and (b) per targeted population.
Ten studies including 1802 individuals examined the impact of cathartics and alterations in timing of their administration on bowel cleansing [
In a single-center study, Barclay [
Table
Secondary endpoints.
Author, year | Acceptance of preparation strategies ( |
Patients receiving adequate preparation ( |
Willingness to repeat colonoscopy ( |
AE ( |
Hospital stay (days) | Repeat colon examinations ( | |
---|---|---|---|---|---|---|---|
Educational interventions | Chorev, 2006 | NR | 177/209 (overall; not per intervention) | NR | NR | NR | 20/105 |
20/104 | |||||||
Rosenfeld, 2010 | NR | NR | NR | NR | NR | NR | |
Lee, 2015 | 95/103 | 101/103 |
86/103 | 36/103 | NR | NR | |
62/102 | 91/102 |
75/102 | 48/102 | ||||
Ergen, 2016 | NR | NR | NR | NR | 6 | 0/45 | |
5 | 1/40 | ||||||
Chambers, 2017 | NR | 26/26 |
NR | NR | NR | NR | |
12/12 | |||||||
Shah-Khan, 2017 | NR | NR | NR | NR | NR | NR | |
Bowel regimens modification | Seinela, 2003 | 26/35 | 31/35 |
13/35 | 7/35 |
NR | NR |
23/37 | 36/37 |
18/37 | 20/37 | ||||
Reilly, 2004 | NR | NR | NR | NR | NR | NR | |
Muller, 2007 | 32/40 | NR | 32/40 | 6/40 | NR | NR | |
37/40 | 37/40 | 10/40 | |||||
Ell, 2008 | 113/153 | 130/153 | NR | 73/153 | NR | NR | |
82/155 | 134/155 | 86/155 | |||||
Kotwal, 2014 | 33/51 | 43/51 | 36/51 | 36/51 | NR | NR | |
38/52 | 48/52 | 46/52 | 28/52 | ||||
Yang, 2015 | NR | 37/46 |
NR | 26/46 | NR | NR | |
52/54 |
49/54 | 19/54 | |||||
Tae, 2015 | 24/31 | 30/31 |
29/31 | 14/31 | NR | NR | |
18/31 | 29/31 | 30/31 | 14/31 | ||||
Song, 2017 |
50/53 | NR | NR | 5/53 | NR | NR | |
Yadlapati, 2017 | NR | NR | NR | NR | 24/524 | ||
9/445 | |||||||
Pontone, 2018 | 15/22 | NR | NR | 8/22 | 3 | NR | |
16/22 | 6/22 | 6 | |||||
Others | Barclay, 2013 | 31/42 | 39/42 | NR | NR | NR | NR |
18/40 | 34/40 | NR | NR | NR | NR |
Eight studies (16 sets of data) [
Seven studies with 13 sets of data [
Nine studies [
Three studies [
A number of inpatient-related factors may contribute to inadequate bowel cleansing [
Our analysis showed that educating either the patients or the hospital personnel or both may pose certain effect on inpatients’ bowel preparation quality. Educational interventions (paper-based interventions, videos, reeducation phone calls the day before colonoscopy, or in-person education by physicians) have been established from outpatients’ studies as efficient methods to optimize colon preparation outcome [
In addition, our analysis did not find solid evidence to support that specific types of cathartics or alterations in timing of their administration could result in better mucosa visualization. Although several approaches are available, the ideal bowel preparation regimen for inpatients remains to be determined, yet. Given the fact that several predictors of inadequate preparation are to be anticipated (e.g., advanced age, deteriorated health status, multiple medications, and comorbidities), this might be a particularly difficult task [
Since no single intervention has been shown to be efficacious in reaching the optimal level of bowel preparation in inpatients, one could speculate that multiple, combined strategies based on a case by case decision may have the potential to influence the final outcome. Indeed, this is the key message of a recent trial, where implementation of a standardized order set with split-dosing regimen, provision of written educational material to patient, and active nursing facilitation to the process overall resulted in significant positive improvements in the rate of acceptable inpatient bowel preparation [
Core strengths of the meta-analysis are the comprehensive and contemporaneous search strategy, including a recursive search of the literature of selected articles. To the best of our knowledge, this is the first study systematically addressing all available interventions to improve bowel preparation in inpatients.
We acknowledge a series of limitations in our study. The principal limitation lies in the heterogeneity encountered, calling for careful interpretation of our results. The latter mainly arises from the characteristics of the meta-analyzed evidence: retrospective, single-center setting, inadequate statistical power, small samples, and combination of randomized and observational studies, arbitrary classification of the reviewed interventions, and bowel preparation scales used. In an effort to explore the evident heterogeneity, we performed predefined sensitivity analyses; nevertheless, ecological bias cannot be excluded. Even the existing evidence supporting that educational interventions reduce the rate of inadequate colon cleansing could be of higher quality. One could argue that the presence of significant heterogeneity and questionable—in some instances—study’s quality included may challenge the validity of our results; however, our review enhances existing literature by specifically highlighting the potential role of educational interventions in inpatients bowel preparation adequacy and how current studies may still offer guidance in everyday clinical practice. Moreover, information regarding the exact stationary status of inpatients was absent, while concomitant medications were not systematically analyzed. Finally, local factors (e.g., staff availability) that might affect each intervention’s efficacy remain underrated.
In conclusion, this study highlights the inadequate level of bowel preparation in inpatients undergoing colonoscopy, although several interventions have been implemented to increase it. However, educational interventions provided to patients and health care personnel reduce the rate of inadequate colon cleansing.
Part of this study has been presented as a poster during DDW 2018, Washington DC, USA, and as an Oral e-Poster during ESGE Days 2018, Budapest, Hungary.
The authors declare that there is no conflict of interest regarding the publication of this article.
PG and GT acquired the data, performed the analysis, and drafted and approved the manuscript; ISP interpreted data and revised the draft critically for important intellectual content and approved the manuscript; KT conceived the idea, revised the draft critically for important intellectual content, and approved the manuscript. Paraskevas Gkolfakis and Georgios Tziatzios contributed equally to this work.
We would like to express our gratitude to Vikram S. Kotwal who kindly provided further information on his study.
Supplemental Material A: search strategy. Supplemental Material B: preferred reporting items for systematic reviews and meta-analyses (PRISMA) 2009 checklist. Supplemental Material C Table 1: bowel preparation rating scales used in the included studies. Supplemental Material C Table 2: assessment of secondary endpoints. Supplemental Material C Table 3: risk of bias assessment of included randomized studies and authors’ judgement. Supplemental Material C Table 4: risk of bias assessment of included observational studies using the Newcastle-Ottawa Scale. Supplemental Material C Table 5: educational interventions described in the included studies. Supplemental Material D Figure 1: funnel plot of studies included in the meta-analysis assessing (A) the overall adequacy rate and (B) the impact of educational intervention to improve inpatient bowel preparation quality. Supplemental Material D Figure 2: forest plots of studies included in the meta-analysis assessing acceptance of preparation strategies (A), amount of preparation received (B), willingness to repeat the examination (C), and adverse events (D).