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Dependability of esophageal pH-monitoring data in infants on cutoff limits: the oscillatory index
Y Vandenplas1, R Lepoudre, R Helven
1Department of Pediatrics, Vrije Universiteit Brussels, Belgium.
Insights
A small pH error can misinterpret gastroesophageal reflux (GER) data in infants. Introducing an "oscillatory index" (OI) may improve GER diagnosis accuracy by accounting for pH variability.
Area of Science:
- Pediatric Gastroenterology
- Diagnostic Accuracy
- pH Monitoring
Background:
- The established cutoff for pathologic gastroesophageal reflux (GER) is pH 4.00.
- Small variations around this pH threshold can lead to data misinterpretation.
Purpose of the Study:
- To analyze the impact of pH measurement errors on GER diagnosis in infants.
- To propose and evaluate a new parameter, the
- oscillatory index
- (OI), to enhance diagnostic accuracy.
Main Methods:
- Analysis of 173 infant pH monitoring studies.
- Introduction of the "oscillatory index" (OI) measuring pH variation between 3.75 and 4.25.
- Correlation analysis between OI and traditional GER metrics.
Main Results:
- A pH error of 0.25 units led to misinterpretation in 29% of infant cases.
- The OI ranged from 0-42% and showed a strong correlation (r=0.75) with the percentage of time pH was below 4.00.
- Reclassification of data was suggested for 26% of infants based on proposed OI thresholds.
Conclusions:
- The arbitrary nature of the pH 4.00 cutoff can compromise GER diagnosis.
- The proposed "oscillatory index" (OI) offers a potential method to improve the interpretation of infant pH monitoring data.
- Further validation across diverse patient populations and analysis of different oscillatory ranges are recommended.
Abstract:
The cutoff limit for pathologic gastroesophageal reflux (GER) has been arbitrary, although generally accepted determined at pH 4.00. The influence of a small pH error (0.25 pH units above or below pH 4.00) was analyzed in 173 consecutive pH monitorings. This appeared to cause a misinterpretation of the data in 51 of 173 infants (29%). We propose the introduction of a new parameter measuring the percent of time of the total investigation that the recorded pH varies between 4.25 and 3.75: the "oscillatory index" (OI). The index ranged from 0-42%. The higher the OI, the more pH data that are recorded between pH 4.25 and 3.75. The OI is related to the arbitrary aspects of a boundary level. The Pearson correlation coefficient between the percent of time of the investigation the pH was less than 4.00 and the OI was 0.75. If an OI of more than 10% in infants with normal pH-monitoring data of more than 15% in infants with a GER pathology would be considered as abnormal, pH-monitoring data of 45 infants should be considered for reclassification (26%). Prior to general application, this parameter should be evaluated by more centers in different patient populations, and other "oscillatory ranges" should be analyzed.