title: The relationship between esophagoscopic findings and total acid reflux time below pH 4 and pH 5 in the upper esophagus in patients with laryngopharyngeal reflux disease (LPRD).
abstract: OBJECTIVE
  : To investigate the relationship between esophagoscopic findings and total acid reflux time in the upper esophagus in the patients of laryngopharyngeal reflux disease (LPRD), and to evaluate whether pH<5 holding time is appropriate for diagnosing LPRD.
  
  
  METHODS
  : Esophagoscopy and 24-h pH monitoring in the upper esophagus were performed in 29 patients suspected of LPRD and 19 healthy volunteers participated as controls. The total acid reflux times below pH 4 and 5 in the upper esophagus were compared between the LPRD group and the controls. The LPRD group was divided into LPRD with reflux esophagitis (RE) and LPRD without RE, and the total acid reflux times below pH 4 and 5 of these two groups were compared.
  
  
  RESULTS
  : Eight of the 29 (27.6%) LPRD patients had reflux esophagitis. The LPRD group showed a significantly longer acid reflux time than the control group at pH below 5 (P=0.009) but not at pH below 4 (P=0.48). The LPRD with RE had significantly longer acid reflux times below both pH 4 and 5 in the upper esophagus compared to those of the LPRD without RE. The P values using a cut-off value of pH 5 were smaller than that of pH 4 in all statistical results.
  
  
  CONCLUSIONS
  : The LPRD patients showed significantly longer acid reflux time in the upper esophagus than the control group. In the LPRD group, the LPRD with RE patients had more frequent acid exposure in the upper esophagus than the LPRD without RE. A pH level of 5 could be appropriate as a cutoff level for the diagnosis of LPRD in upper esophagus pH monitoring.
authors.affiliation: Department of Otolaryngology, Tokyo Medical University, 6-7-1 Nishishinjuku, Shinjuku-ku, Tokyo 160-0023, Japan.
authors.forename: Ryoji
authors.initials: R
authors.lastname: Tokashiki
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Nakamura
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Hiroya
authors.initials: H
authors.lastname: Yamaguchi
authors.forename: Mamoru
authors.initials: M
authors.lastname: Suzuki
mesh_terms: D016022:Case-Control Studies; D004945:Esophagoscopy; D004947:Esophagus / Q000737:chemistry*; D005260:Female; D005744:Gastric Acid; D005764:Gastroesophageal Reflux / Q000175:diagnosis*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007830:Larynx / Q000737:chemistry*; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D013997:Time Factors