Answers to Key Questions

Why measure quality of life (QoL) in eating disorders?

Eating Disorders treatment has traditionally used change in symptoms and behaviors as outcome measures. These are important, but increasingly Quality of Life is seen as another crucial outcome measure for progressive, patient-centred programs across many health conditions. Quality of Life is the outcome typically most valued by patients and their families - their involvement in treatment is ultimately aimed at a desire for a better life more broadly.

Why not just use Quality of Life scales developed for other conditions (i.e. generic scales)?

Most evidence, including our own, has shown that scales developed specifically for the condition of interest perform better than generic scales. They usually have better face validity (respondents feel that the items make sense and apply to them) and responsiveness (they are able to show greater change with treatment than generic scales). Responsiveness is a critical characteristic if the scale is being used to measure outcome in a clinical trial or to track improvement over time in individual patients.

What about ego-syntonic responding?

EDQLS items were consciously selected to minimize ego-syntonic responding, which is a feature of the illness at some time points for some patients. However, it is impossible to completely eliminate all response distortion in any measurement (including clinical assessment) that relies on self-report. Clinical impression is an important adjunct to Quality of Life measurement. A Manual with tips on how to administer the scale to minimize the impact of ego-syntonic responding is now available and versions of the EDQLS for parents and healthcare providers are available which can be used to corroborate scores.

What is the evidence for its reliability, validity and responsiveness?

In a multi-site Canadian sample the internal consistency reliability of the EDQLS was found to be .96, and construct validity was strongly supported across several comparator instruments. In 3 and 6 month follow-up, the EDQLS has been shown to have very good responsiveness across multiple indicators and in comparison with well-validated generic instruments. The main peer-reviewed publication that describes the development and validation of the instrument can be found at http://www.hqlo.com/content/5/1/23. The publication relating to its responsiveness can be found at http://www.hqlo.com/content/8/1/83

Are there costs associated with using the EDQLS?

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Eating Disorders Quality of Life Scale