They are relatively easy to use, economical, non-invasive, and do not require sophisticated instruments or highly specialised staff. They have to meet scientific standards 10, and satisfy linguistic, cultural and psychometric criteria 11,12. The objective of this study is the linguistic and cultural validation into Spanish of a questionnaire for diagnosing gastroesophageal reflux disease.

Material and Methods   Design A questionnaire for diagnosing GERD was translated and adapted culturally and linguistically into Spanish. It had been compiled from three validated questionnaires in English: Reflux Disease Questionnaire (RDQ), Gastroesophageal Reflux Disease Impact Scale GERD (GIS) and Gastrointestinal Symptom Rating Scale (GSRS). This questionnaire has a cut-off of 8 (score between 0 and 18), sensitivity of 65% and specificity of 71% for diagnosing GERD. Higher GerdQ scores were associated with more frequent GERD.13 The version to be validated culturally and linguistically is a short self-administered questionnaire which makes it possible to assess the symptoms and to diagnose GERD on the basis of the frequency and severity of heartburn, reflux and epigastric pain. It consists of 6 items, each with four response options, corresponding to the number of days on which symptoms appear. The standardised process of translation and back-translation14 was used to adapt the English questionnaire linguistically, obtaining a pre-final version (Appendix 1).