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Real-world evidence of water exchange colonoscopy improving adenoma detection rates: A propensity score-matched
Ying-Ju Chao1, Yu-Hsi Hsieh1,2, Chia-Pei Tang1,2
1Division of Gastroenterology, Department of Internal Medicine, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chiayi, Taiwan.
Background:
Randomized trials show that water exchange (WE) colonoscopy improves adenoma detection rate (ADR), but its effectiveness and workflow trade-offs in routine, high-volume practice remain uncertain.
Objectives:
To evaluate the real-world performance of WE versus conventional air insufflation for adenoma detection, bowel preparation quality, and procedure efficiency.
Design:
Retrospective propensity score matched cohort study.
Methods:
Outpatient colonoscopies performed from January 2019 through October 2024 at a high-volume Taiwanese center were analyzed. WE procedures were matched 1:1 with air insufflation controls on prespecified covariates. The primary outcome was ADR. Secondary outcomes included segment-specific detection, advanced adenomas detection, sessile serrated lesion detection, bowel preparation quality, and procedure times.
Results:
The matched cohort included 4,322 colonoscopies (2,161 per group). WE increased ADR by 14.0 percentage points (57.9% vs 44.0%; P < 0.001), corresponding to a number needed to treat of 8. The largest gain occurred in the right colon (right-sided ADR 31.8% vs 18.0%; P < 0.001). WE increased detection of adenomas ≥ 10 mm (8.7% vs 6.7%; P = 0.014) and sessile serrated lesions (1.9% vs 1.0%; P = 0.011). WE improved bowel preparation (adequate preparation 97.4% vs 88.4%; P < 0.001; total BBPS 7.5 vs 6.4; P<.001). Total procedure time was longer with WE (22.6 vs 15.6 minutes; P < 0.001), primarily due to longer insertion (11.0 vs 6.0 minutes; P < 0.001).
Conclusions:
In real-world, high-volume practice, WE substantially improved neoplasia detection and bowel cleansing, with the greatest benefit in the right colon and persistence of effect against a high-performing air insufflation baseline. The time cost was predictable, supporting WE as an effective insertion technique when maximizing diagnostic yield is prioritized.
