pH fluctuations versus reflux episodes in patients with gastroesophageal reflux disease: their optimal thresholds and significance in diagnosis.

In physiological and pathological conditions, pH monitoring in the esophagus shows small variations as well as more pronounced deflections. However, only the latter are traditionally taken into account in 24-hour pH monitoring analysis. The present study was designed to establish optimal thresholds of pH fluctuations versus reflux episodes in separating physiological and pathological gastroesophageal reflux (GER) and to evaluate their significance in the diagnosis. Twenty-four-hour intraesophageal pH monitoring and endoscopy were performed in 62 patients with GER symptoms and in 42 healthy controls. The results showed that the percentages of the time with pH fluctuations in patients with and without esophagitis and in healthy controls were, on average, 12.65, 9.5 and 2.76% in 24 h, respectively, and the respective percentages of the time with reflux episodes in the same groups in 24 h were, on average, 3.12, 2.04 and 0.18%, respectively. Using a receiver-operating-characteristic curve analysis, less than 6.7% of the time with pH fluctuations and less than 0.1% of the time with reflux episodes were defined as the combined thresholds for physiological versus pathological reflux. The sensitivity of the combined thresholds for the detection of GER patients with and without esophagitis was 96.7 and 90%, respectively, and their specificity for the diagnosis of patients with abnormal GER was 100%. It is concluded that pH fluctuations and reflux episodes, when evaluated together, are more useful for classifying patients with GER and their combined thresholds yield higher diagnostic accuracy in assessing patients with gastroesophageal disease.