title: Evaluation of symptom index in identifying gastroesophageal reflux disease-related noncardiac chest pain.
abstract: BACKGROUND
  Symptom index (SI), which represents the percentage of perceived gastroesophageal reflux-related symptoms that correlate with esophageal acid reflux events (pH <4), has been suggested as a measure to improve diagnosis of gastroesophageal reflux (GER)-related noncardiac chest pain (NCCP). Because no study has evaluated the value of the symptom index in NCCP patients, data to support this claim have yet to be elucidated.
  
  
  OBJECTIVE
  To evaluate the value of SI in identifying gastroesophageal reflux disease (GERD)-related NCCP patients.
  
  
  METHODS
  Patients enrolled in this study were referred by a cardiologist after a comprehensive work-up excluded a cardiac cause for their chest pain. All patients underwent upper endoscopy to determine esophageal inflammation and 24-hour esophageal pH monitoring to assess esophageal acid exposure. Patients were instructed to record all chest pain episodes during the pH test. Patients with a positive SI (> or =50%) underwent the proton pump inhibitors (PPI) test, which is a therapeutic trial using a short course of high dose PPI.
  
  
  RESULTS
  A total of 94 patients with NCCP were included in this study. Forty-seven (50%) had either a positive upper endoscopy or an abnormal pH test and were considered GERD-Positive. Forty-seven patients (50%) had both tests negative and were considered GERD-Negative. Total number of reflux episodes and percent total, supine and upright time pH less than 4, were significantly higher in the GERD-Positive group as compared with the GERD-Negative group (P < 0.0001, P < 0.0001, P = 0.0045, and P < 0.0001 respectively). Only 9 (19.1%) patients in the GERD-Positive group and 5 (10.6%) patients in the GERD-Negative group had a positive SI (p = ns). Eight (89%) out of the 9 patients who had a positive SI in the GERD-Positive group and 2 (40%) out of 5 patients in the GERD-Negative group responded to the PPI test.
  
  
  CONCLUSIONS
  Positive SI is relatively uncommon in NCCP patients, regardless if GERD is present or absent. Hence, symptom index provides very little improvement in diagnosing GERD-related NCCP.
authors.affiliation: Section of Gastroenterology, Department of Medicine, Southern Arizona VA Health Care System and University of Arizona Health Science Center, 3601 S. 6th Avenue, Tucson, AZ 85723, USA.
authors.forename: Roy
authors.initials: R
authors.lastname: Dekel
authors.forename: Stephanie D
authors.initials: SD
authors.lastname: Martinez-Hawthorne
authors.forename: R Jose
authors.initials: RJ
authors.lastname: Guillen
authors.forename: Ronnie
authors.initials: R
authors.lastname: Fass
mesh_terms: D000136:Acid-Base Equilibrium; D002637:Chest Pain / Q000175:diagnosis* / Q000209:etiology; D020776:Endoscopes, Gastrointestinal; D005260:Female; D005764:Gastroesophageal Reflux / Q000150:complications / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018670:Monitoring, Ambulatory / Q000379:methods; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index