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Quality of life in functional dyspepsia: responsiveness of the Nepean Dyspepsia Index and development of a new 10‐item short form
Author(s) -
Talley N. J.,
Verlinden M.,
Jones M.
Publication year - 2001
Publication title -
alimentary pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.308
H-Index - 177
eISSN - 1365-2036
pISSN - 0269-2813
DOI - 10.1046/j.1365-2036.2001.00900.x
Subject(s) - medicine , cronbach's alpha , quality of life (healthcare) , index (typography) , placebo , internal consistency , psychometrics , gerontology , physical therapy , clinical psychology , alternative medicine , pathology , nursing , world wide web , computer science
Background: The Nepean Dyspepsia Index is a reliable and valid measure of quality of life in functional dyspepsia, but responsiveness has been little studied. The Nepean Dyspepsia Index originally contained 42 items designed to measure impairment of a subject’s ability to engage in relevant aspects of their life because of dyspepsia, and their enjoyment of these aspects; in addition, the individual importance of areas was assessed. It was subsequently shortened to 25 items, yielding five sub‐scales. Aim: To test the Nepean Dyspepsia Index’s responsiveness and develop a responsive, very short form. Methods: A randomized, double‐blind controlled trial was performed in 589 patients with documented functional dyspepsia. Symptoms and quality of life were measured at baseline, 2 and 4 weeks. Responsiveness of the Nepean Dyspepsia Index quality‐of‐life section was evaluated by correlation with symptom scores and calculation of standardized changes in scores. Two items from each sub‐scale which best represented the area of life (by factor loadings) were selected to create the 10‐item short form (SF; short form‐Nepean Dyspepsia Index). Internal consistency was assessed by Cronbach’s alpha and responsiveness was assessed as above. Results: The Nepean Dyspepsia Index quality‐of‐life scales demonstrated excellent responsiveness to change in both the active and placebo arms (standardized response means all > 1.0). The Nepean Dyspepsia Index accounted for only 8% of the variance in percentage change in symptoms (by visual analogue scales), indicating that it was evaluating areas of life not covered by symptoms. The 10‐item short form had adequate internal consistency (all scales ≥ 0.70) and all strongly (and significantly) correlated with the long form sub‐scales; it was also highly responsive. Conclusion: The Nepean Dyspepsia Index is a responsive disease‐specific quality‐of‐life measure; the 10‐item short form can be applied in clinical trials of functional dyspepsia.