Reproducibility of 24-Hour Intraesophageal pH Monitoring in Pediatric Patients

Abstract

Objective. Despite the widespread use of 24-hour intraesophageal pH monitoring for evaluation of gastroesophageal reflux in infants and children, there is little published information regarding the reproducibility of ambulatory pH studies in this patient population. The purpose of our study was to evaluate the reproducibility of 24-hour intraesophageal pH monitoring in pediatric patients.

Methods. We prospectively investigated 26 patients with symptoms suggestive of gastroesophageal reflux (14 females and 12 males) ranging in age from 1 month to 18 years (mean, 9.2 years). The patients underwent extended intraesophageal pH monitoring over two consecutive 24-hour periods.

Results. Data analysis revealed that the overall reproducibility of ambulatory 24-hour pH monitoring is only 69% (r = 0.32). Eight of 26 patients had conflicting results on day 1 compared with results on day 2. Of the 8 patients with conflicting results on day 1 versus day 2, 5 had normal studies on day 1, but demonstrated pathologic reflux on day 2. Thus, the false-negative rate for day 1 was 19.2%. The κ statistic calculated for the total time the pH was abnormal was 0.32, with values <0.4 representing poor correlation. Spearman correlation coefficients indicated that the percentage of time with pH <4 (r = 0.64) and the number of reflux episodes (r = 0.71) per 24-hour period are the most reproducible pH parameters.

Conclusion. The reproducibility of 24-hour intraesophageal pH monitoring in the pediatric population is suboptimal. The investigation should be extended or repeated if the result does not correlate with the patient's clinical history.