Objective: To produce and validate for telephone use in Spain a cross-cultural adaptation of the gastroesophageal reflux questionnaire (GERQ) developed by Locke et al.
Material and method: The Spanish version of the questionnaire was developed through translation, assessment of comprehensibility, back translation, and appraisal of applicability. Subsequently, reproducibility was measured by a test-retest procedure in 125 patients, and concurrent validity was evaluated by comparing self-reported questionnaire data against a gastroenterologist's findings from clinical interviews with 50 patients.
Results: The Spanish version showed itself to be easily understandable and widely applicable. Reproducibility for the two cardinal symptoms of gastroesophageal reflux disease (heartburn and acid regurgitation) as measured by the kappa index (95% confidence interval), was 0.85 (0.73-0.97) and 0.81 (0.70-0.92), respectively. With respect to the process of concurrent validation, kappa values (95% confidence interval) for heartburn and acid regurgitation were 0.85 (0.68-1) and 0.91 (0.79-1), respectively. Median kappa for all questions on the questionnaire was 0.75 (range: 0.42 a 1) in the reproducibility analysis and 0.83 (range: 0.44 a 1) in the concurrent validity analysis.
Conclusions: The reproducibility and concurrent validity of the Spanish version of the GERQ is excellent and comparable to that of the original English version.