Assessing the reliability of 12 vs 24 hour esophageal pH-impedance monitoring for gastro-esophageal reflux in infants

Objectives The recommended duration of Esophageal Multichannel Intraluminal Impedance pH (MII pH) monitoring to detect gastro esophageal reflux (GER) is currently 24 hours. This prolonged recording can be challenging in certain circumstances. We aimed to assess the diagnostic reliability of 12h versus 24h MII pH in infants. Methods Retrospective multicenter study assessing MII pH tracings from infants referred for suspect GERD. Each MII pH was analyzed twice as full time recording and in the first 12h, and data were compared. GERD was diagnosed if one of the following occurred: Number of GER episodes ≥100 in 24 hours; proximal GER episodes >44 (acid) or 57 (non acid); Reflux index (percent time with pH <4) >7%; Bolus Exposure Index (BEI) >2.4%; Bolus Clearance Time (BCT) >18s; Symptom index (SI) ≥50%, Symptom Association Probability (SAP) ≥95%. Univariate analysis was performed to compare MII pH data. Results 127 infants were studied. Median age at MII pH was 61 days (interquartile range IQR 27 116), 49 were born preterm. There were no significant differences between the 12h and the 24h analysis regarding the number of total GER and proximal GER events/hour, reflux index, BEI, BCT, positive SI/SAP. GER events lasting >5 minutes/hour were 1.97±0.27 and 1.83±0.44 respectively (p<0.001). The 12h MII pH recording showed 87.7% sensitivity, 75.6% specificity, 89.7% positive predictive value, 71.7% negative predictive value for GERD compared to 24h MII pH. Conclusions 12h MII pH had a good diagnostic performance compared to 24h recording. Only GER events lasting >5 minutes were significantly different between the two, but the clinical significance of this observation is unclear.