Adenoma Detection Rate During Colonoscopy With Water Exchange Technique in Comparison With Water Immersion Technique: Meta-Analysis of Randomized Studies

Abstract

Introduction: Colonoscopy is the preferred procedure for prevention of colorectal cancer by detecting its precursor lesion, adenomas. However, several studies have reported an adenoma miss rate of 10-25% despite technical improvements in endoscopic techniques. Adenoma detection rate(ADR) is an important quality indicator for colonoscopies. Water assisted colonoscopy has been shown to reduce patient discomfort and also improve ADR marginally and there are 2 techniques that are used - water immersion(WI) and water exchange(WE). However there is no meta-analysis comparing ADR between the 2 techniques. Methods: Comprehensive literature search was performed in EMBASE, Scopus, Pubmed, Cochrane databases from 1946 to May 31, 2017 to identify potential articles. MeSH headings included in the search included adenoma detection rate, colonoscopy, water exchange, water immersion, water assist. All references from the identified articles were further searched to find more articles. Studies were included if they were randomized clinical trials(RCT) and reported ADR on cohorts of patients undergoing colonoscopy with WE and WI techniques. Odds ratio of ADR and cecal intubation time were compared between WE and WI. Statistics were done using Revman version 5.3. Results: A total of 128 articles were identified from the search strategy and from articles identified through references and abstracts. A total of 4 RCT studies met the inclusion criteria. Total number of patients included in the analysis was 2229 (1110 in WE group, 1119 in WI group). WE technique improved ADR when compared to WI technique and the results were statistically significant (1.31; 95% CI 1.10-1.55) (image 1). There was no heterogeneity between the studies (I2=0%). Three studies reported mean cecal intubation time and the use of WE increased the cecal intubation time by an average of 4.82 minutes (95% CI 4.19-5.46) or 4 minutes 49 seconds (image 2). Conclusion: WE technique is superior to WI technique with respect to adenoma detection rate. However, the disadvantage of WE in terms of longer cecal intubation time should be taken into account in interpretation of these results. Given that all the 4 studies were RCT and no heterogeneity between the studies, the results of this study are important in current clinical context, as ADR is the most important colonoscopy quality indicator.Figure: Adenoma detection rate.Figure: Mean difference of cecal intubation time.