Structural validation of a quality of life questionnaire (FDDQOL) in patients with functional dyspepsia – Revaluation of a placebo-controlled trial

Introduction Functional dyspepsia (FD) is a highly prevalent disorder with a considerable impact on quality of life. There is a need to find out the factors which represent best the treatment responsiveness of a common rating scale for quality of life. We therefore assessed the latent structure and its stability over time (8 months) of the Functional Digestive Disorders Quality of Life Questionnaire (FDDQOL). Methods We investigated the quality of life in 257 patients with functional dyspepsia at baseline, 2, 4 and 8 weeks of STW 5 (Iberogast® 20 drops tid) or placebo treatment and after 3 and 6 months follow up…