Development and validation of a Functional Dyspepsia-Related Quality of Life (FD-QOL) scale in South Korea

Background: Quality of life (QOL) in patients with functional dyspepsia in South Korea has never been studied, mostly due to the lack of a psychometrically validated disease-specific instrument for measuring the QOL. The aim of the present study was to develop and validate a QOL scale for patients with functional dyspepsia. Methods: A Functional Dyspepsia-Related QOL (FD-QOL) scale was developed and validated as follows: item generation, pilot test, and psychometric test. Patients with functional dyspepsia (n = 220) were recruited from seven university hospitals. The participants were asked to complete the preliminary item-generated FD-QOL, the Short Form-36 (SF-36), and the Index of Dyspepsia Symptoms-Korean (IDS-K). The data were analyzed using factor analysis, correlation, anova, and Cronbach's alpha. Results: Twenty-three items were generated based upon content validity. Factor analysis extracted a four-factor solution, and two items were deleted because they were not loaded significantly on any factor. The FD-QOL was correlated with the SF-36 subscales, of which scores were differentiated according to the levels of dyspepsia symptoms. Cronbach's alpha of the FD-QOL was 0.94. Conclusions: The FD-QOL scale is a rapid and easily applicable instrument with excellent psychometric properties of content, factorial, convergent, and known-groups validity, and internal consistency reliability in Korean patients with functional dyspepsia.