title: Validation of the reflux disease questionnaire for an Italian population of patients with gastroesophageal reflux disease.
abstract: OBJECTIVE
  The reflux disease questionnaire (RDQ) is a very simple questionnaire based on only 12 questions that can be answered and evaluated quickly in a primary care setting, which was already found to be valid and reliable in the diagnosis of gastroesophageal reflux disease (GERD). As an English and a German version of the RDQ exist, but not an Italian one, we aimed at translating the RDQ into Italian and evaluating its reliability for the use of Italian-speaking GERD patients.
  
  
  METHODS
  For the purpose of linguistic validation, we translated backward and forward the original RDQ into Italian and again into English. For the purpose of assessing internal consistency, test-retest, and interrater reliability, 130 GERD patients were used, of whom 57 patients had an endoscopic oesophagitis of grade A to C according to the Los Angeles classification and 63 patients had uninvestigated GERD symptoms but with a frequency of heartburn and/or regurgitation at least twice a week.
  
  
  RESULTS
  After professional translation, the Italian RDQ was judged to retain fully the meaning of the original RDQ. Internal consistency, as judged by the (Cronbach's alpha) was satisfactory, with an overall RDQ scale alpha=0.86 (minimum acceptable value=0.70). Test--retest reliability (Spearman coefficient) was again found to be optimal, with individual item values ranging between 0.74 (for 'pain in the upper stomach: frequency') and 0.90 (for 'burning feeling behind breastbone: severity'). Finally, the correlation coefficient was 0.96 for the total scale and a range of 0.85-0.98 for individual items, indicating extremely satisfactory concordance.
  
  
  CONCLUSIONS
  The Italian RDQ appears to be a simple, reproducible, and reliable tool for the diagnosis of GERD. We believe that this questionnaire is well suited for use, both in primary care settings and in epidemiological studies, in particular for the assessment of so-called typical symptoms.
authors.affiliation: Department of Clinical Sciences, Division of Gastroenterology, L Sacco University Hospital, Milan, Italy. fabio.pace@unimi.it
authors.forename: Fabio
authors.initials: F
authors.lastname: Pace
authors.forename: Pamela
authors.initials: P
authors.lastname: Scarlata
authors.forename: Valentina
authors.initials: V
authors.lastname: Casini
authors.forename: Piercarlo
authors.initials: P
authors.lastname: Sarzi-Puttini
authors.forename: Gabriele Bianchi
authors.initials: GB
authors.lastname: Porro
mesh_terms: D000328:Adult; D000368:Aged; D003431:Cross-Cultural Comparison; D005260:Female; D005764:Gastroesophageal Reflux / Q000175:diagnosis*; D006801:Humans; D007558:Italy; D007802:Language; D008297:Male; D008875:Middle Aged; D011320:Primary Health Care / Q000379:methods; D011594:Psychometrics; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D055815:Young Adult