Psychometric and methodological characteristics of a culturally adjusted gastroesophageal reflux disease questionnaire

Abstract

Population-based data regarding the prevalence of gastroesophageal reflux disease (GERD) in Turkey is lacking. Therefore, a valid and reliable instrument for population-based study of GERD is important. The purpose of the study is to establish the feasibility, reproducibility, reliability and validity of the Turkish version of the GERD questionnaire. The study sample of 630 people was randomly recruited from the 20- to 65-year-old-population of Menderes, Izmir. Face to face interviews were conducted using the Turkish GERD questionnaire. The questionnaire was translated into Turkish, and then test-retest reliability of the study was carried out with 25 individuals. Internal reliability was measured using Cronbach's alpha. Additionally, a validity study was performed at the gastroenterology outpatient clinic at Ege University, Faculty of Medicine (45 people). This Turkish GERD questionnaire was easily understood and completed in a reasonable time by members of the population for whom the survey was intended. For all questions (omitting the demographic questions) kappa statistics were calculated; the median kappa for the outpatient assessment was 0.82. The sensitivity of the questionnaire concerning heartburn was strong and the specificity of the test was weak. By calculating Cronbach's alpha coefficient, we estimated the internal consistency or the reliability of each component. The Cronbach's alpha coefficients were above 0.70. This instrument can be used for large-scale population based studies in Turkey.