Development of a new dyspepsia impact scale: the Nepean Dyspepsia Index N. J. TALLEY 1 , M. HAQUE 2 , J. W. WYETH 2 , N. H. STACE 2 , G. N. J. TYTGAT 3 , V. STANGHELLINI 4 , G. HOLTMANN 5 , M. VERLINDEN 6 & M. JONES 7 1 Department of Medicine, University of Sydney, Nepean Hospital, Penrith, Australia; 2 Department of Gastroenterology, Wellington Hospital, Wellington, New Zealand; 3 Department of Gastroenterology-Hepatology, Amsterdam, the Netherlands; 4 Department of Gastroenterology, University of Bologna, Italy; 5 Department of Internal Medicine, Division of Gastroenterology, University of Essen, Germany; 6 Gastroenterology Venture, Abbott Laboratories, USA; and 7 Instat, Sydney, Australia Accepted for publication 20 September 1998 INTRODUCTION Quality of life is now recognized as an important health outcome, and is frequently measured in clinical and epidemiological studies. 1±3 In clinical trials, quality of life is often used as a secondary outcome to symptom relief, while in health surveys, quality of life information provides valuable insights into the burden of illness amongst diseased populations. 1, 2 Quality of life is particularly useful as an outcome measure in studies of disease that have no obvious biological or clinical markers. In these conditions, symptom control becomes a treatment priority, and in the absence of objective clinical criteria, treatment ef®cacy should be evaluated by its impact on symptoms as well as on patient well-being and functioning. 3±5 Quality of life generally correlates well with symptom severity scores in untreated patients, 3 and improve- ments in quality of life consequent to effective treatment have been reported. 3 SUMMARY Background: There is not at present a suitable disease- speci®c health-related quality of life instrument for uninvestigated dyspepsia and functional (non-ulcer) dyspepsia. Aim: To develop a new multi-dimensional disease- speci®c instrument. Methods: The Nepean Dyspepsia Index (NDI) was designed to measure impairment of a subject's ability to engage in relevant aspects of their life and also their enjoyment of these aspects; in addition, the individual importance of each aspect is assessed. A 42-item quality of life measure was developed and tested, both in out-patients presenting to general practice with upper gastrointestinal complaints (n  113) and in a randomly chosen population- based sample (n  347). Results: Adequate face and content validity was docu- mented by an expert panel. Factor analysis identi®ed four clinically relevant subscales: interference with activities of daily living, work, enjoyment of life and emotional well-being; lack of knowledge and control over the illness; disturbance to eating or drinking; and disturbance to sleep because of dyspepsia. These scales had high internal consistency. Both symptoms and the quality of life scores discriminated dyspepsia from health. Conclusion: The Nepean Dyspepsia Index is a reliable and valid disease-speci®c index for dyspepsia, measuring symptoms and health-related quality of life. Correspondence to: Prof. N. J. Talley, Department of Medicine, University of Sydney, Nepean Hospital, Penrith, NSW 2751, Australia. E-mail: ntalley@blackburn.med.usyd.edu.au Aliment Pharmacol Ther 1999; 13: 225±235. Ó 1999 Blackwell Science Ltd 225