title: Validation of the GerdQ questionnaire for the diagnosis of gastro-oesophageal reflux disease.
abstract: BACKGROUND
  The diagnosis of gastro-oesophageal reflux disease (GERD) remains a challenge as both invasive methods and symptom-based strategies have limitations. The symptom-based management of GERD in primary care may be further optimised with the use of a questionnaire.
  
  
  OBJECTIVE
  To assess the diagnostic validity of the GerdQ questionnaire in patients with symptoms suggestive of GERD.
  
  
  METHODS
  Patients with symptoms suggestive of GERD without alarm features, underwent upper endoscopy, and if normal, pH-metry. Patients were followed for 4 weeks and GerdQ was completed blinded to the investigator at both visits. Reflux oesophagitis or pathological acid exposure was used as diagnostic references for GERD. The diagnostic accuracy for GERD on symptom response to proton pump inhibitor (PPI) was assessed.
  
  
  RESULTS
  Among the 169 patients, a GerdQ cutoff ≥9 gave the best balance with regard to sensitivity, 66% (95% CI: 58-74), and specificity, 64% (95% CI: 41-83), for GERD. The high prevalence of reflux oesophagitis (81%) resulted in a high proportion of true positives, but at the same time a high proportion of false-negatives. Consequently, GerdQ had a high positive predictive value, 92% (95% CI: 86-97), but a low negative predictive value, 22% (95% CI: 13-34), for GERD. Symptom resolution on PPI therapy had high sensitivity, 76% (95% CI: 66-84), but low specificity, 33% (95% CI: 17-53), for GERD.
  
  
  CONCLUSIONS
  GerdQ is a useful complementary tool for the diagnosis of gastro-oesophageal reflux disease in primary care. The implementation of GerdQ could reduce the need for upper endoscopy and improve resource utilisation. Symptom resolution on proton pump inhibitor did not predict gastro-oesophageal reflux disease.
authors.affiliation: Institute of Medicine, University of Bergen, Norway. christian.jonasson@med.uib.no
authors.forename: C
authors.initials: C
authors.lastname: Jonasson
authors.forename: B
authors.initials: B
authors.lastname: Wernersson
authors.forename: D A L
authors.initials: DA
authors.lastname: Hoff
authors.forename: J G
authors.initials: JG
authors.lastname: Hatlebakk
mesh_terms: D000328:Adult; D004724:Endoscopy / Q000379:methods; D005260:Female; D005764:Gastroesophageal Reflux / Q000175:diagnosis* / Q000188:drug therapy / Q000523:psychology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires / Q000592:standards*