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Excerpt
Dear Editor:
We read with great interest the article by Kauer et al.1 concerning an investigation into the role of duodenal juice in the pathogenesis of gastroesophageal reflux disease. It emphasizes the fact that esophageal pH has little bearing on the presence of bile acids in the esophagus, and that for the majority of the time, the pH is at a level at which bile acids are more than capable of causing damage. The authors have used Bilitec 2000 (Synthetics Medical, Stockholm, Sweden) as the tool for detecting duodenal juice in the esophagus: this is technology that has been in clinical practice for 3 to 4 years and was first described in 1988.2 Several clinical studies have been published concerning its use,3-7 but they differ fundamentally from Dr. Kauer's article because they have all used an absorbance threshold of 0.14; below this level, absorbance is said to be due to suspended particles and mucus in gastric juice. However, Dr. Kauer and colleagues1 have used a threshold value of 0.2, and then quote normal values for Bilitec 2000 based on this absorbance threshold.
We recently analyzed the results of 22 reflux patients investigated in our laboratory at both threshold values. This first confirmed that esophageal reflux of duodenal juice correlates well with acid reflux and that it bears no relationship to "alkaline" reflux. At a threshold of 0.14 (and using Dr. Kauer's normal values), 14 patients (64%) had significant duodenal reflux, and 8 patients (36%) did not. At a threshold value of 0.2, using the same normal values, 10 patients (45%) had significant duodenal reflux and 12 (55%) did not (p = 0.06, McNemar's test). Although this is only significant at the 10% level, probably because of the small numbers, four patients (18%) changed from significant reflux to no reflux, and seven patients (32%) had their reflux severity downgraded (up to twice normal indicating mild reflux, 2-3 times normal moderate reflux and above this, severe reflux). Thus, 50% of patients had their reflux grading altered.
Bilitec 2000 is an exciting new tool that may reveal further information regarding the relationship between acid and duodenal reflux in the esophagus. Doubts have been cast over the original validation studies8 and the concerns raised hopefully are being addressed. However, we believe that it is absolutely vital that if results using this new technology in different centers are to be compared meaningfully, normal values must be established using standard criteria and international protocols must be established for its use. Otherwise, further doubts about Bilitec 2000 will be raised.
