A new measure of multimorbid illness and treatment representations: The example of diabetes and depression

Background: Depression is two to three times more common in people with diabetes than in the general population. Although multimorbid diabetes and depression is associated with poor health outcome, existing research has focused on patients' understanding and management of each condition in isolation. This study describes the development and validation of the Diabetes and Depression Representation and Management Questionnaire (DDRMQ), a measure of understanding, management and medication beliefs in people with diabetes and depression. Methods: In Study 1, DDRMQ items were developed through further analysis of an earlier qualitative study and refined through 18 cognitive interviews. In Study 2, 334 adults with diabetes and depression from general practices, diabetes clinics and support groups completed the DDRMQ demographic questions and validating measures. Results: Factor analysis of the DDRMQ using principal axis factoring resulted in a 35 item scale organised into ten subscales. The modified measure had adequate internal and test-retest reliability. Initial evidence of construct validity was also demonstrated. Limitations: Low participant response rates and the high percentage of well-educated white participants limit the generalisability of results. As Study 2 was cross-sectional, future research is needed to establish if different ways of thinking about and managing diabetes and depression can predict patient outcome. Conclusions: The DDRMQ is the first measure of patient understanding, management and medication beliefs in people with established diagnoses of both diabetes and depression. The DDRMQ will facilitate an increased awareness of the patient experience of diabetes and depression and help inform patient centred care and intervention development for people with multiple conditions. (C) 2014 Elsevier B.V. All rights reserved