Study | Subject groups | EGJ-CI (mm Hg·cm) | Notes |

Nicodème et al110 | Controls (n=75) GERD (n=7) Functional (n=45) | 39 (25–55) 18* (8–30) 27 (17 –69) | GERD had +++ abnormal pH-impedance studies vs partial + or − for functional |

Tolone et al111 | Functional (n=39) GERD (n=91) | 22 (10–41) 11* (3–21) | GERD or functional by endoscopy and pH-impedance testing |

Jasper et al112 | Controls (n=65) GERD (n=116) | 63 (50–90) 50* (28 –70) | GERD by pH-metry |

Wang et al113 | Controls (n=21) GERD (n=68) | 35 (26–58) 30* (15 –53) | GERD patients underwent fundoplication |

Xie et al114 | Controls (n=21) Oesophagitis (n=39) NERD (n=38) Hypersensitive (n=21) | 63 (38–83) 22* (20 –31) 26* (15 –38) 30* (19 –44) | Patients differentiated by pH-impedance and symptom correlation |

Ham et al108 | Controls (n=23) Oesophagitis (n=25) NERD (n=16) Non-GERD ((n=91) | 67 (27–79) 28* (4 –63) 26* (15 -–32) 51 (3–153) | Patients with no GERD had negative pH-impedance studies |

Methods of EGJ-CI computation were not uniform between these studies, and this might explain differences in calculated thresholds. NERD: non-erosive reflux disease.

↵*P<0.05 vs controls or comparator.

EGJ-CI, oesophagogastric junction contractile integral; NERD: non-erosive reflux disease.