Assessing 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) survey.

AIMS

To investigate the validity and reliability of the 6-item DAWN2 Impact of Diabetes Profile (DIDP), and the modified 7-item DIDP, which includes assessment of dietary freedom.

METHODS

The online, cross-sectional, Australian MILES-2 survey included the DIDP and other validated measures, to examine convergent, discriminant and known-groups validity. The DIDP was completed by 2207 adults with diabetes (Type 1: n = 1012; Type 2 insulin: n = 504; non-insulin: n = 691). Data were subjected to exploratory factor analysis, internal consistency reliability and univariate statistics, conducted separately by diabetes type/treatment.

RESULTS

The DIDP was highly acceptable: 99% completion rate. One-factor solutions were supported for the 6-item and 7-item DIDP scales, in all diabetes type/treatment groups (variance explained range: 6-item: 59-67%, 7-item: 55-62%), with satisfactory internal consistency (α = 0.85-0.90). Known-groups validity was demonstrated, by diabetes type and complications presence/absence, as was satisfactory convergent and discriminant validity.

CONCLUSIONS

The DIDP meets the need for a brief, contemporary, valid and reliable measure of the perceived impact of diabetes on quality of life, suitable for adults with Type 1 or Type 2 diabetes mellitus. The 6-item and 7-item scales have psychometric equivalence. Use of the seventh item can be informed by research questions.