The Functional Dyspepsia Symptom Diary (FDSD) was developed to address the lack of symptom-focused, patient-reported outcome measures designed for use in functional dyspepsia patients and meeting Food and Drug Administration recommendations for patient-reported outcome instrument development.
Dr Fiona Taylor and colleagues conducted concept elicitation interviews with functional dyspepsia participants to identify symptoms important and relevant to functional dyspepsia patients.
A preliminary version of the FDSD was constructed, then completed by functional dyspepsia participants on an electronic device in cognitive interviews to evaluate the readability, comprehensibility, relevance, and comprehensiveness of the FDSD, and to preliminarily evaluate its measurement properties.
During concept elicitation interviews, the research team noted that 45 participants spontaneously reported 19 symptom concepts.
Of those, 7 symptoms were selected for assessment by the 8-item FDSD.
Cognitive interviews with 57 participants confirmed that participants were able to comprehend and provide meaningful responses to the FDSD, and that the handheld electronic FDSD format was suitable for use in the target population.
The researchers found that scores of the FDSD were well-distributed among response options, and item discrimination indices suggested that the FDSD items differentiate among patients with varying degrees of functional dyspepsia severity.
The team observed that inter-item correlations suggested that no items of the FDSD were capturing redundant information.
Internal consistency estimates and construct-related validity estimates using known-groups methods were within acceptable ranges.
Dr Taylor's team concludes, "The FDSD is a content-valid patient reported outcome measure, with preliminary psychometric evidence providing support for the FDSD’s items and total score."
"Further psychometric evaluations are recommended to more fully test the FDSD’s score performance and other measurement properties in the target patient population."