[The symptom index: progress in the analysis of esophageal pH metry]

Commercially available pH-monitoring systems include one or more event markers which should allow correlation between reflux episodes and symptoms. However, the clinical relevance of this feature has not yet been thoroughly investigated. In this prospective study, we attempted to establish whether the use of an event marker could improve the accuracy of intraesophageal pH-monitoring and if a correlation between symptoms, as detected by event markers and esophageal exposure to acid could be shown. One hundred seven patients were studied. Only 47 p. 100 used the event marker during 24 h pH-metry. There was no statistical significance in the incidence of gastroesophageal reflux (GER i.e. time spent below pH 4 greater than 4.2 p. 100), age and socioeconomic status between patients who used the marker and those who did not. A concordance index was calculated by dividing the number of reflux episodes associated with a marked event by the total number of marked events. In 50 p. 100 of the 16 patients who used the marker and had GER, the concordance index was greater than 75 p. 100. On the contrary, only 4 out of 35 patients without GER had a concordance index greater than 75 p. 100 (p less than 0.003). Finally, the index was less than 25 p. 100 in 4 patients with GER and in 22 without GER (p less than 0.02). The lowest pH reached within the esophagus was virtually identical during all the reflux episodes, regardless of marker pressing.(ABSTRACT TRUNCATED AT 250 WORDS)