Assessing the impact of diabetes on quality of life

Using data from the MILES-2 study, we have validated the DAWN Impact of Diabetes Profile

by Prof Jane Speight

For several decades, ‘quality of life’ has been recognised as an important clinical outcome. In some conditions, where health cannot be improved, it may be the most important outcome. In a condition such as diabetes, quality of life may be assessed alongside objective markers of glucose management (such as HbA1c). It is an important way of assessing whether a medical treatment has benefits. Quality of life is subjective, which means it can only be assessed by asking a person for their opinion. For most purposes, this means using questionnaires. There are several questionnaires to assess the impact of diabetes on quality of life (as discussed here). Many of them are lengthy or complex. There is a need for a brief measure focused on the aspects of life that are considered important for most people’s lives.

The DAWN2 Impact of Diabetes Profile (DIDP) was designed for inclusion in the multi-national DAWN2 study. This 6-item questionnaire assesses the perceived impact of diabetes on six key dimensions of life: physical health, finances, relationships with family/friends, leisure activities, work/studies, emotional well-being. However, until now, researchers have not examined whether the DIDP items can be combined into a single scale to assess the overall impact of diabetes across all aspects of life measured. We set out to do this, separately by diabetes type/treatment, using data from the Diabetes MILES-2 study.

The DIDP was highly acceptable to adults with type 1 and type 2 diabetes: 99% of respondents completed the questionnaire. Our analyses showed that the item scores can be combined to form a total score for the original 6-item questionnaire. We also added a 7th item, focused on dietary freedom, as this had been shown in previous work to be important for quality of life in people with diabetes. Our analyses also supported combining all 7 items to form a total score. An important aspect of validity testing is whether a measure can differentiate between groups where they are expected to differ. Our ‘Known-groups validity’ tests of the 6- and 7-item DIDP measures showed significant differences in the impact of diabetes between people with different types of diabetes, and between those with and without complications.

We can conclude that the DIDP meets the need for a brief, contemporary, valid and reliable measure of the perceived impact of diabetes on quality of life. It is suitable for completion by adults with type 1 or type 2 diabetes. In terms of psychometric properties, the 6-item and 7-item scales are equivalent, and use of the 7th item can be informed by research questions. Further work is now needed to see whether the DIDP is useful in clinical trials to assess differences in the impact of medical treatments.

To read more about quality of life, check out our previous blogs on this topic here.

Holmes-Truscott E, Skovlund S, Hendrieckx C, Pouwer F, Peyrot M, Speight JAssessing the perceived impact of diabetes on quality of life: Psychometric validation of the DAWN2 Impact of Diabetes Profile in the second Diabetes MILES – Australia (MILES-2) surveyDiabetes Research and Clinical Practice, 2019; 253-263.

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