Adenoma detection rate is a key colonoscopy quality indicator in Western clinical literature. 

Dr Yanglin Pan and colleagues from California, USA reported that low adenoma detection rate prompted us to assess novel methods to improve performance. 

Western retrospective reports suggested that water exchange could increase adenoma detection rate. 

However, most of these studies used pain score or intubation rate as the primary outcome. 

The team tested the hypothesis that water exchange significantly increases adenoma detection rate among Chinese colonoscopists, and designed a prospective randomized controlled trial using adenoma detection rate as their primary outcome.

The team performed a prospective, randomized controlled trial at 6 centers in China. 

Screening, surveillance, and diagnostic cases were randomized to be examined by water exchange or traditional air insufflation method. 

The team's primary outcome was adenoma detection rate.

From 2014 to 2015, 3,303 patients were randomized to water exchange and air insufflation. 

The researchers found that baseline characteristics were comparable. 

Overall adenoma detection rate was 18% with water exchange, and 13% with air insufflation. 

The team noted that adenoma detection rate in screening patients using air insufflation was 26% in males, and 16% in females. 

The researchers found that adenoma detection rate in screening patients aged >50 years old was 29% in water exchange, and 23% with air insufflation. 

The increase by water exchange was reproducibly observed in all indication categories, and significant in screening and diagnostic cases. 

The limitation imposed by the unblinded investigators was mitigated by comparable inspection times in cases without polyps, similar adenoma per positive colonoscopy, and reproducible enhancement of adenoma detection rate, and adenoma per colonoscopy by water exchange across all 8 investigators.

Dr Pan's team comments, "This prospective study confirms Western retrospective data that water exchange significantly improves adenoma detection rate among Chinese colonoscopists."

"Water exchange may be superior to air insufflation for screening colonoscopy in China."

"Colonoscopists elsewhere with low adenoma detection rate might consider evaluating water exchange for performance improvement."