Comparison of Adenoma Detection Rate Between Water Exchange Colonoscopy and Air Insufflation Colonoscopy: A Meta-Analysis

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 exchange(WE)technique has been shown to reduce postprocedural discomfort and also helpful in difficult colonoscopy. However its impact on ADR when compared to air insufflation(AI) has yield mixed results. We aimed to do a meta-analysis to answer this question 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, air insufflation. All references from the identified articles were further searched to find more articles. Studies were included if they reported ADR on cohorts of patients undergoing colonoscopy with WE and AI techniques. Odds ratio of ADR and cecal intubation time were compared between WE and AI. Statistical analysis were done using Revman version 5.3. Results: A total of 156 articles were identified from the search strategy and from articles identified through references and abstracts. A total of 11 studies met the inclusion criteria. Total number of patients included in the analysis was 6976(3483 in WE group, 3493 in AI group). WE technique improved ADR when compared to AI technique and the results were statistically significant(1.41; 95% CI 1.26-1.58) (image 1). There was no heterogeneity between the studies (I2=0%). Six studies reported cecal intubation time and the use of WE increased the cecal intubation time by an average of 3.42 minutes (95% CI 1.63-5.21) or 3 minutes 25 seconds.(image 2). Conclusion: WE technique is superior to AI technique with respect to adenoma detection rate during colonoscopy. However the disadvantage of WE in terms of longer cecal intubation time should be taken into account in interpretation of these results. WE also improves patient experience by reducing postprocedural abdominal discomfort and should be considered at least in patients with difficult colonoscopies.Figure: Adenoma detection rate.Figure: Mean difference of cecal intubation time.