Long-term risks of respiratory diseases in patients infected with SARS-CoV-2: a longitudinal, population-based cohort study

Background

In the post-pandemic era, growing apprehension exists regarding the potential sequelae of COVID-19. However, the risks of respiratory diseases following SARS-CoV-2 infection have not been comprehensively understood. This study aimed to investigate whether COVID-19 increases the long-term risk of respiratory illness in patients with COVID-19.

Methods

In this longitudinal, population-based cohort study, we built three distinct cohorts age 37-73 years using the UK Biobank database; a COVID-19 group diagnosed in medical records between January 30th, 2020 and October 30th, 2022, and two control groups, a contemporary control group and a historical control group, with cutoff dates of October 30th, 2022 and October 30th, 2019, respectively. The follow-up period of all three groups was 2.7 years (the median (IQR) follow-up time was 0.8 years). Respiratory outcomes diagnosed in medical records included common chronic pulmonary diseases (asthma, bronchiectasis, chronic obstructive pulmonary disease (COPD), interstitial lung disease (ILD), pulmonary vascular disease (PVD), and lung cancer. For the data analysis, we calculated hazard ratios (HRs) along with their 95% CIs using Cox regression models, following the application of inverse probability weights (IPTW).

Findings

A total of 3 cohorts were included in this study; 112,311 individuals in the COVID-19 group with a mean age (±SDs) of 56.2 (8.1) years, 359,671 in the contemporary control group, and 370,979 in the historical control group. Compared with the contemporary control group, those infected with SARS-CoV-2 exhibited elevated risks for developing respiratory diseases. This includes asthma, with a HR of 1.49 and a 95% CI 1.28-1.74; bronchiectasis (1.30; 1.06-1.61); COPD (1.59; 1.41-1.81); ILD (1.81; 1.38-2.21); PVD (1.59; 1.39-1.82); and lung cancer (1.39; 1.13-1.71). With the severity of the acute phase of COVID-19, the risk of pre-described respiratory outcomes increases progressively. Besides, during the 24-months follow-up, we observed an increasing trend in the risks of asthma and bronchiectasis over time. Additionally, the HR of lung cancer for 0-6 month follow-up was 3.07 (CI 1.73-5.44), and the association of lung cancer with COVID-19 disease disappeared at 6-12 month follow-up (1.06; 0.43-2.64) and at 12-24 months (1.02; 0.45-2.34). Compared to those with one SARS-CoV-2 infection, reinfected patients were at a higher risk of asthma (3.0; 1.32-6.84), COPD (3.07; 1.42-6.65), ILD (3.61; 1.11-11.8), and lung cancer (3.20; 1.59-6.45). Similar findings were noted when comparing with a historical cohort serving as a control group, including asthma (1.31; 1.13-1.52); bronchiectasis (1.53; 1.23-1.89); COPD (1.41; 1.24-1.59); ILD (2.53; 2.05-3.13); PVD (2.30; 1.98-2.66); and lung cancer (2.23; 1.78-2.79).

Interpretation

Our research suggests that patients with COVID-19 may have an increased risk of developing respiratory diseases, and the risk increases with the severity of infection and reinfection. Even during the 24-month follow-up, the risk of asthma and bronchiectasis continued to increase. Hence, implementing appropriate follow-up strategies for these individuals is crucial to monitor and manage potential long-term respiratory health issues. Additionally, the increased risk in lung cancer in the COVID-19 individuals was probably due to the diagnostic tests conducted and incidental diagnoses.

Funding

The National Natural Science Foundation of China of China Regional Innovation and Development Joint Foundation; National Natural Science Foundation of China; Program for High-level Foreign Expert Introduction of China; Natural Science Foundation for Distinguished Young Scholars of Guangdong Province; Guangdong Basic and Applied Basic Research Foundation; Climbing Program of Introduced Talents and High-level Hospital Construction Project of Guangdong Provincial People's Hospital; VA Clinical Merit and ASGE clinical research funds.

Comparison of Right Colon Flat Polyp Detection Rate by Water Exchange Versus Water Immersion-pooled Results of Data File of 3 Published Reports

GOALS

We tested the hypothesis that water exchange (WE) achieved a significantly higher right colon flat polyp detection rate (rFPDR) than water immersion (WI).

BACKGROUND

Current endoscopy methods provide real-time morphology but not histopathology. Flat serrated polyps are difficult to find during colonoscopy. In 2022 2 studies reported that the serrated polyp detection rate (SPDR) significantly inversely predicted the development of interval cancers. In 2021 1 systemic review with meta-analysis showed that WE, but not WI increased SPDR. The relative contributions of WE and WI on rFPDR are unknown.

STUDY

Individual patient data from 3 reports comparing air insufflation, WI, and WE were pooled. Multiple logistic regression analysis was used to assess the factors associated with a higher rFPDR.

RESULTS

The pooled data showed that the rFPDR of air insufflation, WI, and WE were 15.4%, 14.1%, and 19.4% ( P =0.009), respectively. After adjusting for age and withdrawal time, multiple logistic regression analysis revealed that WE, when compared with WI, was significantly associated with a higher rFPDR (adjusted odds ratio[aOR]=1.53, P =0.002). Analysis of data on pathology and size were omitted to avoid duplicating our earlier publications.

CONCLUSIONS

Significantly higher rFPDR was achieved by WE. Water exchange rather than WI merits consideration for use to maximize rFPDR. Removal of flat polyps, and by inference serrated polyps, ensures their optimal management to minimize the occurrence of interval cancers. The potential benefit of WE in maximizing SPDR and minimizing interval cancers deserves evaluation in long-term randomized controlled studies focused on flat polyps detection.

Risks of digestive diseases in long COVID: evidence from a population-based cohort study

BACKGROUND

In the post-pandemic era, a wide range of COVID-19 sequelae is of growing health concern. However, the risks of digestive diseases in long COVID have not been comprehensively understood. To investigate the long-term risk of digestive diseases among COVID patients.

METHODS

In this large-scale retrospective cohort study with up to 2.6 years follow-up (median follow-up: 0.7 years), the COVID-19 group (n = 112,311), the contemporary comparison group (n = 359,671) and the historical comparison group (n = 370,979) predated the COVID-19 outbreak were built using UK Biobank database. Each digestive outcome was defined as the diagnosis 30 days or more after the onset of COVID-19 infection or the index date. Hazard ratios (HRs) and corresponding 95% confidence intervals (CI) were computed utilizing the Cox regression models after inverse probability weighting.

RESULTS

Compared with the contemporary comparison group, patients with previous COVID-19 infection had higher risks of digestive diseases, including gastrointestinal (GI) dysfunction (HR 1.38 (95% CI 1.26 to 1.51)); peptic ulcer disease (HR 1.23 (1.00 to 1.52)); gastroesophageal reflux disease (GERD) (HR 1.41 (1.30 to 1.53)); gallbladder disease (HR 1.21 (1.06 to 1.38)); severe liver disease (HR 1.35 (1.03 to 1.76)); non-alcoholic liver disease (HR 1.27 (1.09 to 1.47)); and pancreatic disease (HR 1.36 (1.11 to 1.66)). The risks of GERD were increased stepwise with the severity of the acute phase of COVID-19 infection. Even after 1-year follow-up, GERD (HR 1.64 (1.30 to 2.07)) and GI dysfunction (HR 1.35 (1.04 to 1.75)) continued to pose risks to COVID-19 patients. Compared to those with one SARS-CoV-2 infection, reinfected patients were at a higher risk of pancreatic diseases (HR 2.57 (1.23 to 5.38)). The results were consistent when the historical cohort was used as the comparison group.

CONCLUSIONS

Our study provides insights into the association between COVID-19 and the long-term risk of digestive system disorders. COVID-19 patients are at a higher risk of developing digestive diseases. The risks exhibited a stepwise escalation with the severity of COVID-19, were noted in cases of reinfection, and persisted even after 1-year follow-up. This highlights the need to understand the varying risks of digestive outcomes in COVID-19 patients over time, particularly those who experienced reinfection, and develop appropriate follow-up strategies.

Genetically predicted causal associations between periodontitis and psychiatric disorders

BACKGROUND

Psychiatric disorders have serious harm to individuals' lives with high disease burden. Observational studies reported inconsistent associations between periodontitis and some psychiatric disorders, and the causal correlations between them remain unknown.

OBJECTIVE

This study aims to explore the causal associations between periodontitis and psychiatric disorders.

METHODS

A series of two-sample Mendelian randomisation (MR) analyses were employed using genome-wide association study summary statistics for periodontitis in adults from Gene-Lifestyle Interactions in Dental Endpoints Consortium and 10 psychiatric disorders from Psychiatric Genomics Consortium. Causal effects were primarily estimated using the inverse-variance weighted (IVW) method. Various sensitivity analyses were also conducted to assess the robustness of our results.

FINDINGS

The MR analysis suggested that genetically determined periodontitis was not causally associated with 10 psychiatric disorders (IVW, all p>0.089). Furthermore, the reverse MR analysis revealed that 10 psychiatric disorders had no causal effect on periodontitis (IVW, all p>0.068). We discovered that all the results were consistent in the four MR analytical methods, including the IVW, MR-Egger, weighted median and weighted mode. Besides, we did not identify any heterogeneity or horizontal pleiotropy in the sensitivity analysis.

CONCLUSIONS

These results do not support bidirectional causal associations between genetically predicted periodontitis and 10 common psychiatric disorders. Potential confounders might contribute to the previously observed associations.

CLINICAL IMPLICATIONS

Our findings might alleviate the concerns of patients with periodontitis or psychiatric disorders. However, further research was warranted to delve into the intricate relationship between dental health and mental illnesses.

Outcome of Water Exchange and Air Insufflation Colonoscopy Performed by Supervised Trainee and Their Assessment of the Training Experience

GOALS

The hypotheses that supervised trainees would provide a more favorable assessment of the learning experience and could achieve superior results with water exchange (WE) compared with air insufflation were tested.

BACKGROUND

WE decreased pain, increased cecal intubation rate (CIR), and polyp detection rate (PDR).

STUDY

In a prospective pilot observational study, the trainees were taught WE in unsedated and WE and air insufflation in alternating order in sedated veterans. Trainee scores and procedural outcomes were tracked.

RESULTS

83 air insufflation and 119 WE cases were included. Trainee evaluations of the respective methods were scored based on a 5-point scale [1 (strongly agree) to 5 (strongly disagree, with lower scores being more favorable]. Evaluation scores [mean (SD)] were as follows: my colonoscopy experience was better than expected: WE 2.02 (1.00) versus air insufflation 2.43 (1.19), P =0.0087; I was confident with my technical skills using this method: WE 2.76 (0.91) versus air insufflation 2.85 (0.87), P =0.4822. Insertion time was 40 (21) min for WE and 30 (20) min for air insufflation ( P =0.0008). CIR were 95% (WE, unsedated); 99% (WE, overall), and 89% (air insufflation, overall). WE showed significantly higher CIR (99% vs. 89%, P =0.0031) and PDR (54% vs. 32%, P =0.0447).

CONCLUSIONS

The long air insufflation insertion time indicated the trainees were inexperienced. The significantly longer WE insertion time confirmed that learning WE required extra time. This pilot study revealed that supervised trainees reported more favorable learning experience with WE and equivalent confidence in technical skills scores. They completed both unsedated and sedated colonoscopy in over 89% of cases achieved significantly higher CIR and PDR with WE than air insufflation. It appeared that trainee education in WE might be an acceptable alternative to augment air insufflation to meet the challenges of training posed by traditional air insufflation colonoscopy.

Habitual fish oil use and risk of COVID-19-related outcomes: Evidence from a large scale cohort study and Mendelian randomization analysis

BACKGROUND & AIMS

Previous findings for the effects of fish oil on COVID-19-related outcomes remain largely inconclusive and controversy persists. Large population-based studies in real-life settings are required to explore the impact of habitual fish oil use on Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, Coronavirus disease 2019 (COVID-19)-related hospitalization and death. To investigate the associations between habitual fish oil use and SARS-CoV-2infection, COVID-19-related outcome.

METHODS

Cohort study based on the UK Biobank. 466,572 participants were enrolled. For Mendelian randomization (MR) study, single-nucleotide variants were selected for exposures of fish-oil-derived n-3 PUFAs, including docosapentaenoic acid (DPA).

RESULTS

146,969 (31.5%) participants reported their habitual fish oil use at baseline. Compared with non-fish-oil-users, the hazard ratios for habitual users were 0.97 (95% confidence interval [CI] 0.94 to 0.99) for SARS-CoV-2 infection, 0.92 (95% CI 0.85 to 0.98) for COVID-19-related hospitalization and 0.86 (95% CI 0.75 to 0.98) for COVID-19-related death. MR showed that a higher level of circulating DPA is casually associated with a lower risk of severe COVID-19 (IVW, odds ratio = 0.26, 95% CI 0.08-0.88, P = 0.030).

CONCLUSIONS

In this large cohort, we found that habitual fish oil use was significantly associated with lower risks of SARS-CoV-2 infection, hospitalization and death from COVID-19. MR analyses further support a possible causal role of DPA, one of the components of fish oil and valid biomarkers of dietary intake, in reducing the risk of severe COVID-19.

Dissecting shared genetic architecture between obesity and multiple sclerosis

BACKGROUND

Observational studies have associated obesity with an increased risk of multiple sclerosis (MS). However, the role of genetic factors in their comorbidity remains largely unknown. Our study aimed to investigate the shared genetic architecture underlying obesity and MS.

METHODS

By leveraging data from genome-wide association studies, we investigated the genetic correlation of body mass index (BMI) and MS by linkage disequilibrium score regression and genetic covariance analyser. The casualty was identified by bidirectional Mendelian randomisation. Linkage disequilibrium score regression in specifically expressed genes and multimarker analysis of GenoMic annotation was utilised to explore single-nucleotide polymorphism (SNP) enrichment at the tissue and cell-type levels. Shared risk SNPs were derived using cross-trait meta-analyses and Heritability Estimation from Summary Statistics. We explored the potential functional genes using summary-data-based Mendelian randomization (SMR). The expression profiles of the risk gene in tissues were further examined.

FINDINGS

We found a significantly positive genetic correlation between BMI and MS, and the causal association of BMI with MS was supported (β = 0.22, P = 8.03E-05). Cross-trait analysis yielded 39 shared risk SNPs, and the risk gene GGNBP2 was consistently identified in SMR. We observed tissue-specific level SNP heritability enrichment for BMI mainly in brain tissues for MS in immune-related tissues, and cell-type-specific level SNP heritability enrichment in 12 different immune cell types in brain, spleen, lung, and whole blood. The expressions of GGNBP2 were significantly altered in the tissues of patients with obesity or MS compared to those of control subjects.

INTERPRETATION

Our study indicates the genetic correlation and shared risk genes between obesity and MS. These findings provide insights into the potential mechanisms behind their comorbidity and the future development of therapeutics.

FUNDING

This work was funded by the National Natural Science Foundation of China (82171698, 82170561, 81300279, and 81741067), the Program for High-level Foreign Expert Introduction of China (G2022030047L), the Natural Science Foundation for Distinguished Young Scholars of Guangdong Province (2021B1515020003), Natural Science Foundation of Guangdong Province (2022A1515012081), the Foreign Distinguished Teacher Program of Guangdong Science and Technology Department (KD0120220129), the Climbing Programme of Introduced Talents and High-level Hospital Construction Project of Guangdong Provincial People's Hospital (DFJH201803, KJ012019099, KJ012021143, and KY012021183), and in part by VA Clinical Merit and ASGE clinical research funds (FWL).

Lack of Causal Associations of Inflammatory Bowel Disease with Parkinson's Disease and Other Neurodegenerative Disorders

BACKGROUND

Observational studies have indicated associations between inflammatory bowel disease (IBD) and neurodegenerative diseases, including Parkinson's disease (PD).

OBJECTIVE

To evaluate the causal associations of IBD with PD and other selected neurodegenerative disorders using updated data.

METHODS

Bidirectional two-sample Mendelian randomization studies using genome-wide association studies summary statistics of IBD and PD.

RESULTS

We found a lack of evidence for the causal association of IBD on PD (odds ratio [OR], 1.014; 95% confidence interval [CI], 0.967-1.063; P = 0.573). Reverse analysis also indicated no evidence of a causal effect for PD on IBD (OR, 0.978; 95% CI, 0.910-1.052; P = 0.549). The causality between IBD and Alzheimer's disease, amyotrophic lateral sclerosis, and multiple sclerosis was unfounded (all P > 0.05).

CONCLUSIONS

The updated analyses provide no clear evidence for causal associations of IBD with PD or the other three neurodegenerative diseases. Potential confounders might contribute to the previously observed associations, and further investigations are warranted. © 2023 International Parkinson and Movement Disorder Society.

Randomized Trial Comparing Left Colon Mucus Production Using Water Versus Saline During Water Exchange Colonoscopy

INTRODUCTION

Water-assisted colonoscopy increases left colon mucus production; however, the effect of saline on mucus production is unclear. We tested the hypothesis that saline infusion may reduce mucus production in a dose-related manner.

METHODS

In a randomized trial, patients were assigned to colonoscopy with CO2 insufflation, water exchange (WE) with warm water, 25% saline, or 50% saline. The primary outcome was the Left Colon Mucus Scale (LCMS) score (5-point scale). Blood electrolytes were measured before and after saline infusion.

RESULTS

A total of 296 patients with similar baseline demographics were included. The mean LCMS score for WE with water was significantly higher than that for WE with saline and CO2 (1.4 ± 0.8 [WE water] vs 0.7 ± 0.6 [WE 25% saline] vs 0.5 ± 0.5 [WE 50% saline] vs 0.2 ± 0.4 [CO2]; overall P < 0.0001), with no significant difference between the 25% and 50% saline groups. The left colon adenoma detection rate (ADR) was highest in the 50% saline group, followed by the 25% saline and the water groups (25.0% vs 18.7% vs 13.3%) but the difference was not significant. Logistic regression showed water infusion as the only predictor of moderate mucus production (odds ratio, 33.3; 95% confidence interval, 7.2-153.2). No acute electrolyte abnormalities were documented indicating a safe modification.

CONCLUSIONS

The use of 25% and 50% saline significantly inhibited mucus production and numerically increased ADR in the left colon. Evaluation of the impact of mucus inhibition by saline on ADR may refine the outcomes of WE.

Associations of habitual glucosamine use with SARS-CoV-2 infection and hospital admission and death with COVID-19: Evidence from a large population based cohort study

The coronavirus disease 2019 (COVID-19) pandemic has led to a fundamental number of morbidity and mortality worldwide. Glucosamine was indicated to help prevent and control RNA virus infection preclinically, while its potential therapeutic effects on COVID-19-related outcomes are largely unknown. To assess the association of habitual glucosamine use with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, hospital admission, and mortality with COVID-19 in a large population based cohort. Participants from UK Biobank were reinvited between June and September 2021 to have SARS-CoV-2 antibody testing. The associations between glucosamine use and the risk of SARS-CoV-2 infection were estimated by logistic regression. Hazard ratios (HRs) and 95% confidence intervals (CIs) for COVID-19-related outcomes were calculated using COX proportional hazards model. Furthermore, we carried out propensity-score matching (PSM) and stratified analyses. At baseline, 42 673 (20.7%) of the 205 704 participants reported as habitual glucosamine users. During median follow-up of 1.67 years, there were 15 299 cases of SARS-CoV-2 infection, 4214 cases of COVID-19 hospital admission, and 1141 cases of COVID-19 mortality. The fully adjusted odds ratio of SARS-CoV-2 infection with glucosamine use was 0.96 (95% CI: 0.92-1.01). The fully adjusted HR were 0.80 (95% CI: 0.74-0.87) for hospital admission, and 0.81 (95% CI: 0.69-0.95) for mortality. The logistic regression and Cox proportional hazard analyses after PSM yielded consistent results. Our study demonstrated that habitual glucosamine use is associated with reduced risks of hospital admission and death with COVID-19, but not the incidence of SARS-CoV-2 infection.

Investigating Causality and Shared Genetic Architecture between Neurodegenerative Disorders and Inflammatory Bowel Disease

Published observational studies have revealed the connection between neurodegenerative disorders and inflammatory bowel disease (IBD), whereas the causal association remains largely unclear. Our study aims to assess the causality and identify the shared genetic architecture between neurodegenerative disorders and IBD. Two-sample Mendelian randomization analyses were performed to assess the causality between IBD and neurodegenerative disorders (amyotrophic lateral sclerosis [ALS], Alzheimer's disease [AD], Parkinson's disease [PD], and multiple sclerosis [MS]). Shared genetic loci, functional interpretation, and transcriptomic profiles were further investigated in ALS and IBD. We identified that genetic predisposition to IBD was suggestively associated with lower odds of ALS (odds ratio [OR] 0.96, 95% confidence interval [CI] 0.94 to 0.99). In contrast, IBD was not genetically associated with an increased risk of AD, PD, or MS (and vice versa). Two shared genetic loci (rs6571361 and rs7154847) were derived, and SCFD1, G2E3, and HEATR5A were further identified as novel risk genes with enriched functions related to membrane trafficking. G2E3 was differentially expressed and significantly correlated with SCFD1 in patients with ALS or IBD. Our study reveals the suggestively protective role of IBD on ALS, and does not support the causality of AD, PD, or MS on IBD (and vice versa). Our findings indicate possible shared genetic architecture and pathways between ALS and IBD. These results provide insights into the pathogenesis and therapeutics of IBD and neurodegenerative disorders.

A survey of colonoscopists with and without in-depth knowledge of water-aided colonoscopy

BACKGROUND AND AIM

Endoscopy featured water-aided colonoscopy (WAC) as novel in the Innovation Forum in 2011. Gastrointestinal Endoscopy published a modified Delphi consensus review (MDCR) that supports WAC for clinical practice in 2021. We tested the hypothesis that experience was an important predictor of WAC use, either as water immersion (WI), water exchange (WE), or a combination of WI and WE.

METHODS

A questionnaire was sent by email to the MDCR authors with an in-depth knowledge of WAC. They responded and also invited colleagues and trainees without in-depth knowledge to respond. Logistic regression analysis was used with the reasons for WAC use treated as the primary outcome. Reports related to WAC post MDCR were identified.

RESULTS

Of 100 respondents, > 80% indicated willingness to adopt and modify practice to accommodate WAC. Higher adenoma detection rate (ADR) incentivized WE use. Procedure time slots ≤ 30 and > 30 min significantly predicted WI and WE use, respectively. Co-authors of the MDCR were significantly more likely to perform WAC (odds ratio [OR] = 7.5, P = 0.037). Unfamiliarity with (OR = 0.11, P = 0.02) and absence of good experience (OR = 0.019, P = 0.002) were associated with colonoscopists less likely to perform WAC. Reports related to WAC post MDCR revealed overall and right colon WE outcomes continued to improve. Network meta-analyses showed that WE was superior to Cap and Endocuff. On-demand sedation with WE shortened nursing recovery time.

CONCLUSIONS

An important predictor of WAC use was experience. Superior outcomes continued to be reported with WE.

Safety and effectiveness of underwater cold snare resection without submucosal injection of large non-pedunculated colorectal lesions

Background and study aims  Adverse events are uncommon with cold snaring, but cold techniques are generally reserved for lesions ≤ 9 mm out of concern for incomplete resection or inability to mechanically resect larger lesions. In a non-distended, water-filled lumen, colorectal lesions are not stretched, enabling capture and en bloc resection of large lesions. We assessed the effectiveness and safety of underwater cold snare resection (UCSR) without submucosal injection (SI) of ≥ 10 mm non-pedunculated, non-bulky (≤ 5 mm elevation) lesions with small, thin wire snares. Patients and methods  Retrospective analysis of an observational cohort of lesions removed by UCSR during colonoscopy. A single endoscopist performed procedures using a small thin wire (9-mm diameter) cold or (10-mm diameter) hybrid snare. Results  Fifty-three lesions (mean 15.8 mm [SD 6.9]; range 10-35 mm) were removed by UCSR from 44 patients. Compared to a historical cohort, significantly more lesions were resected en bloc by UCSR (84.9 % [45/53]; P  = 0.04) compared to conventional endoscopic mucosal resection (EMR) (64.0 % [32/50]). Results were driven by high en bloc resection rates for 10- to 19-mm lesions (97.3 % [36/37]; P  = 0.01). Multiple logistic regression analysis adjusted for potential confounders showed en bloc resection was significantly associated with UCSR compared to conventional EMR (OR 3.47, P  = 0.027). Omission of SI and forgoing prophylactic clipping of post-resection sites did not result in adverse outcomes. Conclusions  UCSR of ≥ 10 mm non-pedunculated, non-bulky colorectal lesions is feasible with high en bloc resection rates without adverse outcomes. Omission of SI and prophylactic clipping decreased resource utilization with economic benefits. UCSR deserves further evaluation in a prospective comparative study.

Polyp detection and false-positive rates by computer-aided analysis of withdrawal-phase videos of colonoscopy of the right-sided colon segment in a randomized controlled trial comparing water exchange and air insufflation

BACKGROUND AND AIMS

Water exchange (WE) improves lesion detection but misses polyps because of human limitations. Computer-aided detection (CADe) identifies additional polyps overlooked by the colonoscopist. Additional polyp detection rate (APDR) is the proportion of patients with at least 1 additional polyp detected by CADe. The number of false positives (because of feces and air bubble) per colonoscopy (FPPC) is a major CADe limitation, which might be reduced by salvage cleaning with WE. We compared the APDR and FPPC by CADe between videos of WE and air insufflation in the right-sided colon.

METHODS

CADe used a convolutional neural network with transfer learning. We edited and coded withdrawal-phase videos in a randomized controlled trial that compared right-sided colon findings between air insufflation and WE. Two experienced blinded endoscopists analyzed the CADe-overlaid videos and identified additional polyps by consensus. An artifact triggered by CADe but not considered a polyp by the reviewers was defined as a false positive. The primary outcome was APDR.

RESULTS

Two hundred forty-five coded videos of colonoscopies inserted with WE (n = 123) and air insufflation (n = 122) methods were analyzed. The APDR in the WE group was significantly higher (37 [30.1%] vs 15 [12.3%], P = .001). The mean [standard deviation] FPPC related to feces (1.78 [1.67] vs 2.09 [2.09], P = .007) and bubbles (.53 [.89] vs 1.25 [2.45], P = .001) in the WE group were significantly lower.

CONCLUSIONS

CADe showed significantly higher APDR and lower number of FPPC related to feces and bubbles in the WE group. The results support the hypothesis that the strengths of CADe and WE complement the weaknesses of each other in optimizing polyp detection.

Investigating regulatory patterns of NLRP3 Inflammasome features and association with immune microenvironment in Crohn's disease

INTRODUCTION

Crohn's disease is characterized of dysregulated inflammatory and immune reactions. The role of the NOD-like receptor family, pyrin domain-containing 3 (NLRP3) inflammasome in Crohn's disease remains largely unknown.

METHODS

The microarray-based transcriptomic data and corresponding clinical information of GSE100833 and GSE16879 were obtained from the Gene Expression Omnibus (GEO) database. Identification of in the NLRP3 inflammasome-related genes and construction of LASSO regression model. Immune landscape analysis was evaluated with ssGSEA. Classification of Crohn's-disease samples based on NLRP3 inflammasome-related genes with ConsensusClusterPlus. Functional enrichment analysis, gene set variation analysis (GSVA) and drug-gene interaction network.

RESULTS

The expressions of NLRP3 inflammasome-related genes were increased in diseased tissues, and higher expressions of NLRP3 inflammasome-related genes were correlated with generally enhanced immune cell infiltration, immune-related pathways and human leukocyte antigen (HLA)-gene expressions. The gene-based signature showed well performance in the diagnosis of Crohn's disease. Moreover, consensus clustering identified two Crohn's disease clusters based on NLRP3 inflammasome-related genes, and cluster 2 was with higher expressions of the genes. Cluster 2 demonstrated upregulated activities of immune environment in Crohn's disease. Furthermore, four key hub genes were identified and potential drugs were explored for the treatment of Crohn's disease.

CONCLUSIONS

Our findings indicate that NLRP3 inflammasome and its related genes could regulate immune cells and responses, as well as involve in the pathogenesis of Crohn's disease from transcriptomic aspects. These findings provide in silico insights into the diagnosis and treatment of Crohn's disease and might assist in the clinical decision-making process.

Sessile serrated adenoma/polyp detection rate of water exchange, Endocuff, and cap colonoscopy: A network meta-analysis

BACKGROUND AND AIM

Sessile serrated adenoma/polyp (SSA/P) may contribute to interval cancer. In a recent meta-analysis, water exchange (WE) was shown to be superior to Endocuff and cap colonoscopy at adenoma and advanced adenoma detection. The strong positive correlation between adenoma detection rate (ADR), advanced adenoma detection rate (AADR), and sessile serrated adenoma/polyp detection rate (SSA/PDR) prompted us to hypothesize that WE could significantly improve SSA/PDR compared with Endocuff and cap colonoscopy.

METHODS

The literature was searched for all randomized controlled trials (RCTs) that reported SSA/PDR as an outcome and included the keywords colonoscopy, and water exchange, Endocuff, or cap. We performed traditional network meta-analyses with random effect models comparing SSA/PDR of each method using air insufflation as the control and reported the odds ratios (ORs) with 95% confidence interval (CI). Performances were ranked based on P-score.

RESULTS

A total of 531 articles resulted from initial keywords search. Eleven RCTs were included in the analysis. A total of 7856 patients underwent air insufflation, WE, Endocuff, or cap colonoscopy. WE significantly increased SSA/PDR (OR 2.04; 95% CI 1.33-3.13). Endocuff (OR 1.15; 95% CI 0.94-1.41) and cap (OR 1.08; 95% CI 0.42-2.74) did not significantly impact SSA/P detection. P-scores for WE (0.96), Endocuff (0.49), cap (0.37), and air insufflation (0.17) suggested that WE had the highest SSA/PDR. The results did not change after adjusting for mean withdrawal time and indication for colonoscopy.

CONCLUSION

Water exchange significantly increases SSA/PDR and is superior to Endocuff and cap colonoscopy at detecting SSA/P.

Comparison of Right Colon Adenoma Miss Rates Between Water Exchange and Carbon Dioxide Insufflation: A Prospective Randomized Controlled Trial

GOALS

To test the hypothesis that water exchange (WE), when compared with carbon dioxide (CO2) insufflation, significantly reduces the right colon adenoma miss rate (rAMR) in a blinded randomized controlled trial with cap-assisted colonoscopy.

BACKGROUND

The unblinded consecutive group observational data showed that WE significantly decreased rAMR. The unblinded data are limited by potential bias.

STUDY

Consecutive patients aged 45 years or more were randomized to undergo insertion with WE or CO2. Withdrawal and polypectomy were performed with CO2 in both groups to the hepatic flexure. The colonoscope was reinserted to the cecum. A second colonoscopist re-examined the right colon. The second colonoscopist was unaware, but made a guess, of the initial insertion method. The number of additional adenomas divided by the total number detected in both examinations equaled rAMR.

RESULTS

Among 262 patients (131/group), demographic variables were similar. The body mass index was significantly higher in the WE group. Compared with CO2, WE significantly decreased rAMR [18.0% (33/183) vs. 34.6% (62/179), P=0.0025] and right colon serrated polyp miss rate [17.4% (27/155) vs. 39.3% (33/84), P=0.002]. Multivariate logistic regression analysis showed that WE was an independent predictor of rAMR (odds ratio, 0.42; 95% confidence interval, 0.21-0.86), and so was ≥2 adenomas in the right colon (odds ratio, 2.35; 95% confidence interval, 1.17-4.76). Whether the second colonoscopist guessed the insertion method correctly or not, and demographic and procedure variables were not associated with rAMR.

CONCLUSIONS

The randomized controlled trial validated unblinded observational data showing that WE significantly decreased rAMR and right colon serrated polyp miss rate (clinical trial registration number: NCT03845933).

Comparing right colon adenoma detection rate during water exchange and air insufflation: a double-blind randomized controlled trial

BACKGROUND

Randomized controlled trials (RCTs) have reported that water exchange (WE) produced the highest adenoma detection rate (ADR) but did not evaluate right colon adenoma detection rate (rADR) as a primary outcome and only one of the trials employed blinded colonoscopists. The aim of our study was to determine whether, compared with air insufflation, WE significantly increases rADR and right colon serrated lesion detection rate (rSLDR) and decreases adenoma miss rate (rAMR).

METHODS

This prospective, double-blind RCT was conducted at a regional hospital in Taiwan between December 2015 and February 2020. Standard WE and air insufflation were performed. After cecal intubation, the second blinded endoscopist examined the right colon and obtained rADR (primary outcome) and rSLDR. Then, the primary colonoscopist reinserted the scope to the cecum with WE in both groups and performed a tandem examination of the right colon to obtain rAMR.

RESULTS

There were 284 patients (50.9% male, mean age 58.9 ± 9.4 years) who were randomized to WE (n = 144) or air insufflation (n = 140). The baseline characteristics were similar. The rADR (34.7% vs. 22.3%, p = 0.025), Boston Bowel Preparation Scale scores (mean, 2.6 ± 0.6vs. 2.2 ± 0.6, p < 0.001), rSLDR (18.1% vs. 7.1%, p = 0.007), and rAMR (31.5% vs. 45.2%, p = 0.038) were significantly different between WE and air insufflation.

CONCLUSIONS

The current study demonstrated a significantly higher rADR and rSLDR with the WE method performed by blinded colonoscopists. The impact of the significant findings in this report on the occurrence of interval cancers deserves to be studied.

Heat sink effect of underwater polypectomy in a porcine colon model

BACKGROUND

Underwater polypectomy without the need for submucosal injection has been reported. A heat-sink effect by immersing the polyp in water was proposed but no such experiment has been performed to support the claim. We compared the temperature rise on the serosal side during polypectomy between air- and water-filled colon.

METHOD

Freshly harvested porcine colons were placed in a metal tray with cautery electrode pad attached to its bottom. An upper endoscope was used with a cap and a rubber band mounted to the distal end. A mucosal site was randomly selected and identified on its serosal surface with a marker while suction was applied. Suction was applied again and a ligation band was applied to create a polyp. A cautery snare grasped the artificial polyp just below the band. An assistant placed the tip of a thermometer at the marked site on the serosal surface to record the baseline temperature before cautery and the highest temperature during polypectomy. Seven polypectomies in air and underwater were performed.

RESULTS

Mean (standard deviation) baseline temperature were 23.3 (0.6) °C and 23.4 (0.6) °C in the air and water groups, respectively. The maximum rise in temperature during polypectomy was 6.1 (4.5) °C and 1.4 (1.0) °C in the air and water groups, respectively (P = 0.004).

CONCLUSIONS

The maximum temperature rise during polypectomy was significantly less when polypectomy was performed underwater, supporting the hypothesis that a heat-sink effect does exist during underwater polypectomy.

Comprehensive analysis of proton pump inhibitors and risk of digestive tract cancers

BACKGROUND

For the past two decades, dispute on whether proton pump inhibitor (PPI) leads to digestive tract cancer remains, and emerging studies in recent years still demonstrate inconsistent results, which continues to perpetuate concerns over the safety of PPI use. We performed a systematic review and meta-analysis, with comprehensive evaluation by Bradford Hill criteria of causation, to assess the effect of PPI use on digestive tract cancers.

METHODS

Medline, Embase and Web of Science databases were searched for observational studies published up to 15th January 2021. Pooled relative risks (RRs) were estimated via random effects models. Cumulative defined daily dose- and duration-risk relationships using restricted cubic spline and fractional polynomial models were investigated. Bradford Hill criteria were applied to evaluate causation. PROSPERO Registration: CRD42020211103.

RESULTS

Thirty-two publications containing 4,355,254 participants were included. PPI use is associated with an increased risk of overall digestive tract cancers (RR = 1.63, 95% confidence interval (CI) 1.33 to 2.00). PPI use is correlated with increased risks of gastric cancer (RR = 1.78, 95% CI 1.38 to 2.31), pancreatic cancer (RR = 1.72, 95% CI 1.05 to 2.82) and liver cancer (RR = 1.62, 95% CI 1.04 to 2.52), but not of esophageal cancer (RR = 2.06, 95% CI 0.65 to 6.57) and colorectal cancer (RR = 1.24, 95% CI 0.93 to 1.66). The association between PPI and digestive tract cancers is stronger in people with minimal exposure. When cumulative defined daily dose or duration increases, the risks decline and become non-significant. Evaluation by Bradford Hill criteria indicates weak evidence of causation.

CONCLUSIONS

A causal relationship between PPI use and digestive tract cancers is not supported by the evidence in the current review. Concerns over carcinogenic side-effects of PPI might be unfounded.

GIE Editorial Board top 10 topics: advances in GI endoscopy in 2020

The American Society for Gastrointestinal Endoscopy's Gastrointestinal Endoscopy Editorial Board reviewed a systematic literature search of original endoscopy-related articles published during 2020 in Gastrointestinal Endoscopy and 10 other high-impact medical and gastroenterology journals. Votes from each individual board member were tallied to identify a consensus list of the 10 most significant topic areas in GI endoscopy over the calendar year of study using 4 criteria: significance, novelty, impact on national health, and impact on global health. The 10 areas identified were as follows: artificial intelligence in endoscopy, coronavirus disease 2019 and GI practice, third-space endoscopy, lumen-apposing metal stents, single-use duodenoscopes and other disposable equipment, endosonographic needle technology and techniques, endoscopic closure devices, advances in GI bleeding management, improvements in polypectomy techniques, and bariatric endoscopy. Each board member contributed a summary of important articles relevant to 1 to 2 topic areas, leading to a collective summary that is presented in this document of the "top 10" endoscopic advances of 2020.

Water-assisted colonoscopy: an international modified Delphi review on definitions and practice recommendations

BACKGROUND AND AIMS

Since 2008, a plethora of research studies has compared the efficacy of water-assisted (aided) colonoscopy (WAC) and underwater resection (UWR) of colorectal lesions with standard colonoscopy. We reviewed and graded the research evidence with potential clinical application. We conducted a modified Delphi consensus among experienced colonoscopists on definitions and practice of water immersion (WI), water exchange (WE), and UWR.

METHODS

Major databases were searched to obtain research reports that could potentially shape clinical practice related to WAC and UWR. Pertinent references were graded (Grading of Recommendations, Assessment, Development and Evaluation). Extracted data supporting evidence-based statements were tabulated and provided to respondents. We received responses from 55 (85% surveyed) experienced colonoscopists (37 experts and 18 nonexperts in WAC) from 16 countries in 3 rounds. Voting was conducted anonymously in the second and third round, with ≥80% agreement defined as consensus. We aimed to obtain consensus in all statements.

RESULTS

In the first and the second modified Delphi rounds, 20 proposed statements were decreased to 14 and then 11 statements. After the third round, the combined responses from all respondents depicted the consensus in 11 statements (S): definitions of WI (S1) and WE (S2), procedural features (S3-S5), impact on bowel cleanliness (S6), adenoma detection (S7), pain score (S8), and UWR (S9-S11).

CONCLUSIONS

The most important consensus statements are that WI and WE are not the same in implementation and outcomes. Because studies that could potentially shape clinical practice of WAC and UWR were chosen for review, this modified Delphi consensus supports recommendations for the use of WAC in clinical practice.

The Effectiveness of Right- vs Left-lateral Starting Position in Unsedated Diagnostic Colonoscopy with Modified-water Immersion Method: A Randomized Controlled Trial Study

Objective

A colonoscopy study in sedated patients with air insufflation showed that right-lateral starting position (RLP) improved abdominal discomfort and reduced cecal intubation time. The aim of this study was to determine if RLP vs left-lateral starting position (LLP) may produce similar results in unsedated patients examined with a modified-water immersion (m-WI) method.

Methods

Consecutive patients for diagnostic colonoscopy meeting the inclusion criteria were randomized. Patients and colonoscopist were unblinded. The m-WI method entailed suction during insertion not only for fecal debris evacuation but also to facilitate passage through difficult or angulated colonic flexures. Water was infused as needed when any difficulty was encountered during insertion. A bowel visualization scale (BVS) (0=totally blurred visualization; 1=blurred lumen visualization; 2=small fecal debris with clear mucosa visualization; 3= clear visualization) was used to evaluate the interference of fecal debris with cecal intubation rate and time.

Results

A total of 142 patients (72 in RLP and 70 in LLP) were enrolled. The respective pain score, visual analog scale, (VAS) and cecal intubation rate were not significantly different. The cecal intubation time was nearly significantly different (13.4±4.5 min vs 11.7±5.4 min; p=0.054) and was significantly different in the constipation subgroup (16.0±3.5 min vs 8.6±3.8 min; p=0.001). The cecal intubation time based on BVS showed significant difference between RLP and LLP in Scale 2 (13.9±4.6 min vs 10.3±4.2 min; p=0.003) and Scale 2 and 3 combined (13.2±4.3 min vs 10.6±4.8 min; p=0.01), respectively.

Conclusion

RLP did not improve the pain score, and LLP showed better performance in unsedated m-WI colonoscopy patients (ClinicalTrial.gov, NCT03489824).

A review of water exchange and artificial intelligence in improving adenoma detection

Water exchange (WE) and artificial intelligence (AI) have made critical advances during the past decade. WE significantly increases adenoma detection and AI holds the potential to help endoscopists detect more polyps and adenomas. We performed an electronic literature search on PubMed using the following keywords: water-assisted and water exchange colonoscopy, adenoma and polyp detection, artificial intelligence, deep learning, neural networks, and computer-aided colonoscopy. We reviewed relevant articles published in English from 2010 to May 2020. Additional articles were searched manually from the reference lists of the publications reviewed. We discussed recent advances in both WE and AI, including their advantages and limitations. AI may mitigate operator-dependent factors that limit the potential of WE. By increasing bowel cleanliness and improving visualization, WE may provide the platform to optimize the performance of AI for colonoscopies. The strengths of WE and AI may complement each other in spite of their weaknesses to maximize adenoma detection.

GIE Editorial Board top 10 topics: advances in GI endoscopy in 2019

The American Society for Gastrointestinal Endoscopy's GIE Editorial Board reviewed original endoscopy-related articles published during 2019 in Gastrointestinal Endoscopy and 10 other leading medical and gastroenterology journals. Votes from each individual member were tallied to identify a consensus list of 10 topic areas of major advances in GI endoscopy. Individual board members summarized important findings published in these 10 areas of disinfection, artificial intelligence, bariatric endoscopy, adenoma detection, polypectomy, novel imaging, Barrett's esophagus, third space endoscopy, interventional EUS, and training. This document summarizes these "top 10" endoscopic advances of 2019.

Covid-19 pandemic impact on colonoscopy service and suggestions for managing recovery

Background and aim  As the post-peak phase of the epidemic is approaching, there is an urgent need of an action plan to help resume endoscopy activity. To manage the Covid-19 pandemic-imposed backlog of postponed colonoscopy examinations, an efficient approach is needed. The practice of on-demand sedation with benzodiazepines and/or opiates will allow most patients to complete a water-aided examination with minimal or no sedation. Other methods reported to minimize patient discomfort during colonoscopy can be used, in addition to water-aided techniques. Unsedated or minimally sedated patients who do not require recovery or require a shorter one allow rapid turnaround. The practice obviates the need for assistance with deep sedation from anesthesiologists, who may be in short supply. Trainee education in water-aided colonoscopy has been demonstrated to confer benefits. This review provides some insights into the impact of Covid-19 on endoscopy services, challenges ahead, and possible solutions to help recovery of colonoscopy work and training.

Impact of new techniques on adenoma detection rate based on meta-analysis data

The high incidence of colorectal cancer and the occurrence of interval cancers after screening colonoscopy support the need to develop methods to increase adenoma detection rate (ADR). This review focuses on the importance of ADR and the impact of new techniques on ADR based on meta-analysis data. The low-cost interventions (such as water-aided colonoscopy, second observation, and dynamic position change) were effective in increasing ADR. So were enhanced imaging techniques and add-on devices. Increase with higher cost interventions such as newer scopes is uncertain. Water exchange (WE) has the highest ADR compared with water immersion, air insufflation, and carbon dioxide insufflation. Second observation with forward or retroflexed views improved the right colon ADR. Add-on devices result in only modest improvement in ADR, of particular help in low performing endoscopists. The second-generation narrow-band imaging (NBI) provided a two-fold brighter image than the previous system. The improvement in ADR with NBI required the “best” quality bowel preparation. New endoscopic techniques incur various additional costs, nil for WE, small for tip attachments but large for the newer scopes. In conclusion, one or more of the above methods to improve ADR may be applicable in Taiwan. A comparison of these approaches to determine which is the most cost-effective is warranted.

Underwater versus conventional endoscopic resection of nondiminutive nonpedunculated colorectal lesions: a prospective randomized controlled trial (with video)

BACKGROUND AND AIMS

Incomplete resection of colorectal neoplasia decreases the efficacy of colonoscopy. Conventional resection (CR) of polyps, performed in a gas-distended colon, is the current standard, but incomplete resection rates of approximately 2% to 30% for nondiminutive (>5 mm), nonpedunculated lesions are reported. Underwater resection (UR) is a novel technique. The aim of this study was to determine the incomplete resection rates of colorectal lesions removed by UR versus CR.

METHODS

In a randomized controlled trial, patients with small (6-9 mm) and large (≥10 mm) nonpedunculated lesions were assigned to CR (gas-distended lumen) or UR (water-filled, gas-excluded lumen). Small lesions in both arms were removed with a dedicated cold snare. For CR, large lesions were removed with a hot snare after submucosal injection. For UR, large lesions were removed with a hot snare without submucosal injection. Four-quadrant biopsy samples around the resection sites were used to evaluate for incomplete resection.

RESULTS

Four hundred sixty-two eligible polyps (248 UR vs 214 CR) from 255 patients were removed. Incomplete resection rates for UR and CR were low and did not differ (2% vs 1.9%, P = .91). UR was performed significantly faster for lesions ≥10 mm in size (10-19 mm, 2.9 minutes vs 5.6 minutes, P < .0001); ≥20 mm, 7.3 minutes vs 9.5 minutes, P = .015).

CONCLUSIONS

Low incomplete resection rates are achievable with UR and CR. UR is effective and safe with the advantage of faster resection and potential cost savings for removal of larger (≥10 mm) lesions by avoiding submucosal injection. As an added approach, UR has potential to improve the cost-effectiveness of colonoscopy by increasing efficiency and reducing cost while maintaining quality. (Clinical trial registration number: NCT02889679.).

Feasibility of sedation on demand in Taiwan using water exchange and air insufflation: A randomized controlled trial

BACKGROUND AND AIM

Completion of colonoscopy without sedation eliminates sedation cost and complications. Reported in the United States and Europe, on-demand sedation is not routine practice in Taiwan. Water exchange (WE), characterized by infusion and nearly complete removal of infused water during insertion, reduces insertion pain compared to air insufflation (AI) during colonoscopy. We evaluated the feasibility of on-demand sedation in Taiwan. In a randomized controlled trial of WE vs AI colonoscopy, we also aimed to determine if WE augmented the implementation by reducing insertion pain and decreasing sedation requirement.

METHODS

This prospective patient-blinded study randomized patients to AI or WE (75 patients/group) to aid insertion. The primary outcome was the proportion of patients completing without sedation.

RESULTS

In the AI and WE groups, 76.0% and 93.3% (P = 0.006) completed without need for sedation, respectively. The WE group had lower insertion pain score (mean [SD]) (4.0 [2.9] vs 2.1 [2.6], P < 0.001), lower doses of propofol (25.7 [52.7] mg vs 9.1 [35.6] mg, P = 0.012), and less time in the recovery room (3.4 [7.4] vs 1.5 [5.5], P = 0.027) than the AI group. Patient satisfaction scores and willingness to repeat if needed in the future were similar.

CONCLUSION

On-demand sedation was feasible in Taiwan. The completion rate without sedation was high in patients (76.0% with standard AI) open to the option (no prior intent to receive the standard of full or minimal sedation). WE augmented the implementation by reducing insertion pain and decreasing sedation requirement without adversely affecting patient satisfaction or willingness to repeat.

An overview of deep learning algorithms and water exchange in colonoscopy in improving adenoma detection

Introduction: Among the Gastrointestinal (GI) Endoscopy Editorial Board top 10 topics in advances in endoscopy in 2018, water exchange colonoscopy and artificial intelligence were both considered important advances. Artificial intelligence holds the potential to increase and water exchange significantly increases adenoma detection.Areas covered: The authors searched MEDLINE (1998-2019) using the following medical subject terms: water-aided, water-assisted and water exchange colonoscopy, adenoma, artificial intelligence, deep learning, computer-assisted detection, and neural networks. Additional related studies were manually searched from the reference lists of publications. Only fully published journal articles in English were reviewed. The latest date of the search was Aug10, 2019. Artificial intelligence, machine learning, and deep learning contribute to the promise of real-time computer-aided detection diagnosis. By emphasizing near-complete suction of infused water during insertion, water exchange provides salvage cleaning and decreases cleaning-related multi-tasking distractions during withdrawal, increasing adenoma detection. The review will address how artificial intelligence and water exchange can complement each other in improving adenoma detection during colonoscopy.Expert opinion: In 5 years, research on artificial intelligence will likely achieve real-time application and evaluation of factors contributing to quality colonoscopy. Better understanding and more widespread use of water exchange will be possible.

Water exchange colonoscopy decreased adenoma miss rates compared with literature data and local data with CO2 insufflation: an observational study

Background

Reports showed adenoma miss rates (AMRs) of 22.5–27% in the right colon and 23.4–33.3% in the proximal colon. Missed lesions could contribute to postcolonoscopy cancers. Water exchange (WE) with near-complete removal of infused water during insertion increased adenoma detection rate but the impact on AMR had not been reported. We hypothesized that WE could reduce AMRs. Study 1 compared the AMRs of WE with literature data. Study 2 developed local AMR data with CO₂ insufflation.

Methods

The lead author attended a research seminar in 2017 on WE colonoscopy. For performance improvement, study 1 was undertaken. When data in study 1 confirmed WE produced a considerably lower AMRs in the right and proximal colon, study 2 with CO₂ insufflation was performed.

Results

Eighty-six patients completed each study. In study 1, WE removed 89% of infused water upon arrival to the cecum. The AMRs of right colon (17.5%) and proximal colon (15.5%) were considerably lower than those in the literature. Upon completion of study 2, compared with local data of CO₂ insufflation, WE showed a significantly lower AMR in the right (17.5% vs. 33.8%, P = 0.034) and proximal (15.5% vs. 30.4%, P = 0.018) colon, respectively. The major limitation was that the investigation consisted of two consecutive observational studies, not a randomized controlled trial (RCT).

Conclusions

WE with near-complete (89%) removal of infused water during insertion significantly decreased AMRs in the right and proximal colon compared with literature data and those of CO₂ insufflation in our hands. The provocative data warrant confirmation in a RCT.

Trial registration

NCT03832322 (Retrospectively registered on February 2, 2019).

Underwater polypectomy without submucosal injection for colorectal lesions ≤ 20 mm in size-a multicenter retrospective observational study

BACKGROUND

Underwater polypectomy (UWP) of large (≥ 20 mm) colorectal lesions is well described, but reports of UWP for lesions ≤ 20 mm in size, which account for > 95% of polyps encountered in routine clinical practice, are limited. We assessed the feasibility of UWP in routine practice across various sites for colorectal lesions ≤ 20 mm in size.

METHODS

A multicenter retrospective study was performed on pooled data from nine colonoscopists at 3 U.S., 1 Taiwanese and 2 Italian sites. Outcomes related to UWP on lesions ≤ 20 mm in size were analyzed.

RESULTS

In 117 patients, UWP netted 169 lesions. Polypectomy by hot (HSP, 54%) or cold (CSP, 41%) snare, and cold forceps (CFP, 5%) were performed successfully without endoscopic evidence of residual neoplasia or immediate clinically significant adverse events. The majority (74.6%) were tubular adenomas; 60.9% were from the proximal colon. Histopathologic margins were positive in 4 and unavailable in 26 CSP and 24 HSP specimens. The remainder had negative resection margins on pathologic reports.

CONCLUSION

UWP for colorectal lesions ≤ 20 mm in routine practice across multiple sites confirms the feasibility and acceptability of this technique. Improvement of resection outcomes by UWP in routine practice deserves further evaluation in a randomized controlled trial.

A prospective RCT comparing combined chromoendoscopy with water exchange (CWE) vs water exchange (WE) vs air insufflation (AI) in adenoma detection in screening colonoscopy

Background

A low adenoma detection rate (ADR) increases risks of interval cancers (ICs). Proximal colon flat polyps, e.g. serrated lesions (SLs), are difficult to find. Missed proximal colon flat lesions likely contribute to IC.

Aims

We compared chromoendoscopy with water exchange (CWE), water exchange (WE) and air insufflation (AI) in detecting adenomas in screening colonoscopy.

Methods

After split-dose preparation, 480 veterans were randomized to AI, WE and CWE.

Results

Primary outcome of proximal ADR (55.6% vs 53.4% vs 52.2%, respectively) were similar in all groups. Adenoma per colonoscopy (APC) and adenoma per positive colonoscopy (APPC) were comparable. Detection rate of proximal colon SLs was significantly higher for CWE and WE than AI (26.3%, 23.6% and 11.3%, respectively, p = 0.002). Limitations: single operator; SLs only surrogate markers of but not IC.

Conclusions

When an endoscopist achieves high-quality AI examinations with overall ADR twice (61.6%) the recommended standard (30%), use of WE and CWE does not produce further improvement in proximal or overall ADR. Comparable APC and APPC confirm equivalent withdrawal inspection techniques. WE alone is sufficient to significantly improve detection of proximal SLs. The impact of increased detection of proximal SLs by WE on prevention of IC deserves to be studied. This study is registered at ClinicalTrial.gov (NCT#01607255).

Impact of water exchange colonoscopy on endoscopy room efficiency: a systematic review and meta-analysis

BACKGROUND AND AIMS

Separate randomized controlled trials (RCTs) showed water exchange (WE) colonoscopy outperformed other techniques in minimizing insertion pain and optimizing adenoma detection rate. Longer insertion time required for removal of infused water, residual air, and feces might have hampered its wider adoption. We evaluate the impact of WE compared with air or carbon dioxide insufflation (GAS) on room turnaround efficiency measured by cecal intubation, withdrawal, and total procedure times.

METHODS

With a systematic search in PubMed, Embase, and Cochrane Library, we identified RCTs (published before March 18, 2018) that compared WE with GAS. We focused on parameters of turnaround efficiency and patient-centered outcomes.

RESULTS

We analyzed 8371 subjects from 17 studies. Demographics and indications were comparable. Mean cecal intubation time (± standard deviation) was WE 12.5 ± 6.1 minutes versus GAS 11.1 ± 7.0 minutes, with a mean difference of 1.4 ± 3.4 minutes. Six studies showed significant differences in insertion time, with mean cecal intubation times of 11.6 ± 5.1 minutes for WE versus 7.7 ± 5.2 minutes for GAS, with a mean difference of 3.9 ± 1.1 minutes. Mean withdrawal time was similar. Mean total procedure time was WE 26.0 ± 9.7 versus GAS 24.2 ± 9.6, with a mean difference of 1.8 ± 6.2 minutes. All mean procedure times were significantly different. Patient-centered outcomes revealed that patients examined with WE had significantly lower real-time insertion pain score, less need for sedation, and higher willingness to repeat the procedure.

CONCLUSIONS

Based on parameters of procedural time, the impact of WE colonoscopy on endoscopy room turnaround yields an increase in total procedure time of about 2 minutes and is associated with significant improvement in specific patient-centered outcomes.

Reduction of multitasking distractions underlies the higher adenoma detection rate of water exchange compared to air insufflation - blinded analysis of withdrawal phase videos

Background

Experts have hypothesized that a reduction of multitasking distractions and improved bowel cleanliness can explain why insertion water exchange enhances adenoma detection rate.

Objective

The purpose of this study was to test the role of both distractions during withdrawal and bowel cleanliness in enhancing adenoma detection rate using coded video records of colonoscopy.

Methods

The withdrawal phase of videos of 299 consecutive colonoscopies from two randomized controlled trials comparing water exchange versus air insufflation at a regional hospital in Taiwan were coded. The primary outcome was distractions; activities that preclude full attention being paid to inspection of the mucosa for polyps. A single blinded reviewer collected the data.

Results

There were significant agreements in inter-rater reliability indexes. Compared to air insufflation, water exchange had significantly fewer distractions; higher diagnostic yield (intervention time and number), adenoma detection rate, and Boston Bowel Preparation Scale score. Water exchange had a higher withdrawal technique score (predominantly adequacy of cleaning). The association between increased adenoma detection rate and water exchange was mediated by the number of distractions and withdrawal time, but not the Boston Bowel Preparation Scale score.

Conclusion

The speculation by experts that a reduction of multitasking distractions underlies the significantly higher adenoma detection rate of water exchange is supported by the current study. Increased bowel cleanliness did not contribute to the increased adenoma detection rate by use of water exchange.

Endoscope-connected water pump with high flow rates improves the unsedated colonoscopy performance by water immersion method

Objectives

The aim of this study was to determine if different water pump flow rates influence the insertion time of water immersion method in unsedated patients. We tested the hypothesis that high flow rate (HFR) is more effective than low flow rate (LFR) in facilitating insertion. Clinical registration number: NCT01869296.

Methods

Consecutive symptomatic patients without prior abdominal surgery were consented and enrolled. They were randomized to an HFR (10.4 mL/s) or LFR (1.7 mL/s) group. The patients were not informed about the flow rate of the water pump (single blinded). Patients underwent unsedated colonoscopy examination with standard colonoscope. Demographic and procedural parameters were recorded. Data were analyzed with Student’s t-test or Chi-square test as appropriate.

Results

A total of 132 patients (66 in HFR and 66 in LFR group) were recruited. The HFR group showed significantly shorter cecal intubation time (12.5±6.2 min in HFR vs 16.3±7.3 min in LFR, p=0.004), shorter time to pass rectosigmoid (3.6±2.2 min in HFR vs 6.2±4.6 min in LFR, p<0.001), and lower pain score (4.2±2.8 in HFR vs 5.3±2.6 in LFR, p=0.024). The cecal intubation rate was not significantly different (87.9% in HFR vs 80.3% in LFR, p=0.34), and 29 (14 in HFR and 15 in LFR) patients with signs of colon redundancy were successfully intubated to the cecum after repeated loop reduction and position changes.

Conclusion

Compared to LFR, HFR of the water infusion pump significantly reduced colonoscopy insertion time and pain score in unsedated patients. Significantly shorter time to pass the rectosigmoid appeared to play a contributory role.

Increase your adenoma detection rate without using fancy adjunct tools

The correlation between a low adenoma detection rate (ADR) and interval cancers (ICs) has made ADR one of the most important quality indicators for colonoscopy. Data from nation-wide colorectal cancer (CRC) screening programs showed that there is room for improvement in ADR in order to reduce ICs in Taiwan. Measures with and without adjunct tools have been shown to have the potential to increase ADR, with the latter being more convenient to apply without additional cost. Optimal withdrawal techniques coupled with sufficient withdrawal time, training endoscopists with emphasis on recognition of subtle characteristics of flat lesions, dynamic position changes during the withdrawal phase, removing small polyps found during insertion, and retroflexion in the right colon have all been associated with increased ADR. In particular, water exchange (WE), which is characterized using water in lieu of air and suction removal of infused water during insertion, appears to meet the needs of colonoscopy patients in Taiwan. Analyses of both primary and secondary outcome variables of recently published studies have consistently shown that WE yields higher ADR than traditional air insufflation, even in propofol-sedated patients. Colonoscopists participating in the nationwide CRC screening program in Taiwan should consider applying one or more of the above measures to improve ADR and hopefully reduce ICs.