Published online May 27, 2020. doi: 10.4240/wjgs.v12.i5.236
Peer-review started: December 30, 2019
First decision: April 3, 2020
Revised: April 9, 2020
Accepted: May 5, 2020
Article in press: May 5, 2020
Published online: May 27, 2020
When gastroesophageal reflux contents reach above the upper esophageal sphincter, patients may, in addition to typical reflux symptoms, present with atypical, extraesophageal symptoms related to laryngopharyngeal reflux (LPR). Surgical treatment of LPR has shown to lead to 70% symptom improvement, however no gold standard for the diagnosis of LPR exists. In 2007, the Restech Dx-pH was released as a valid method to measure acid exposure above the upper esophageal sphincter. Recently, a new software update was introduced for analysis of measured pH data and calculation of composite scores. The effect of the changes applied to the new software version have not yet been analyzed.
The aim of this study was to compare results generated by DataView 3 to the most recently released DataView 4, and to validate the new software in a large patient cohort following a standardized protocol. Our results may be especially important when comparing or reproducing results of clinical research studies previously performed using DataView version 3 with data obtained by the new software version 4.
The RYAN Score, the composite score calculated for oropharyngeal pH testing was first introduced in 2009. Normal thresholds and calculating algorithms were determined in 55 healthy subjects. A significant difference between upright and supine values was found, resulting in the development of two separate scores, RYAN Score upright and RYAN Score supine. Parameters used to calculate the RYAN score are percent of time below threshold (pH < 5.5 for upright and pH < 5 for supine), number of episodes and duration of longest episode for upright and supine respectively. DataView 4 introduced changes to the originally validated algorithms of calculation. Changes made included new criteria for when an event is no longer recorded as a single event, symptom button presses are not counted for 5 min after a button press of the same type and subtraction of a cumulative correction factor from each data point collected after 24 h to compensate for a pH drift. Our study compared the scores calculated by DataView 3 to those calculated by 4 as well as the percent of time below threshold for upright and supine periods.
All patients with gastroesophageal reflux disease symptoms were seen in a specialized surgical outpatient clinic for gastrointestinal function testing. Retrospective chart review was performed of all patients presenting with suspected gastroesophageal reflux disease and extraesophageal reflux symptoms, who underwent laryngopharyngeal pH monitoring using the Restech Dx-pH system (Respiratory Technology Corp., Houston, TX, United States) and simultaneous esophageal pH monitoring. DataView 3 and DataView 4 were used to evaluate Restech studies obtained. Diary entries such as mealtimes, supine and upright periods, and symptoms were entered manually to ensure accuracy and precise conversion of data between both software versions. Paired t test was performed for statistical analysis of results.
A total of 174 patients (63.8% female) met inclusion criteria, all suffering from extraesophageal reflux symptoms as well as typical gastroesophageal reflux disease symptoms. Mean RYAN score upright was 48.77 in DataView 3 compared to 22.17 in DataView 4, showing a significant difference (aP = 0.0001). Similar results were shown for supine period (mean RYAN Score DataView 3 5.29 vs 1.42 in DataView 4, cP = 0.0001). For upright periods 80 patients showed a decrease of value of the RYAN score with a mean of -58.9 (mean 51.1% decrease). For supine position 25 patients showed a decrease of value of the RYAN score with a mean of -15.13 [range (-153.44)–(-0.01)], which equals a mean decrease of value of 44.5%. Ten patients showed no oropharyngeal acid exposure in DataView 3, but mild/moderate (n = 7) or severe (n = 3) acid exposure in DataView 4. Correlation with positive esophageal pH measurement was improved in all 10 patients. Since only 24-h studies were available for analysis, a possible improvement of data by applying a new correction factor for pH drift after 24-h could not be examined. Also, for this study, results obtained from the Restech Dx pH were not evaluated separately depending on if the measurement was performed pre- or postoperatively, resulting in a greater heterogeneity of patient’s groups. Further multicentric studies are needed to evaluate the results of our study.
Overall, this study shows that results of DataView 3 and 4 cannot be compared to each other. This may be especially important when comparing results of clinical research studies performed using DataView version 3. However, our data suggests that the new software version may be an improvement, dealing with confounders and improving the value of the Restech pH measurement in the evaluation of LPR.
Further multicentric studies are needed to show the impact of the new software on results previously published on the Restech measurement. In addition, 48-h oropharyngeal pH studies are needed to analyze the impact of the new correction factor applied for pH drift on the measured data.