Promoting Engagement in Type 2 Diabetes Self-Management: Development of the Impact of Glucose Monitoring on Self-Management Scale (IGMSS).

INTRODUCTION: Type 2 diabetes (T2D) management requires behavioural engagement to achieve optimal outcomes. Continuous glucose monitoring (CGM) facilitates self-management. This paper describes the development of the Impact of Glucose Monitoring on Self-Management Scale (IGMSS), assessing the impact of device use (CGM or SMBG) on capability, motivation, and opportunity for self-management.

METHODS: Items were generated from three sources: themes and quotes from a qualitative study of adults with T2D motivated by CGM use; the behaviour change theory of capability, opportunity and motivation; and expert committee review. 42 items were generated assessig personalized knowledge, improved health (Capability), improved relationships, having positive device characteristics (Opportunity) and improved self-management (Motivation). Psychometric evaluation (514 English-speaking Canadians using CGM) produced 22 final items using item-response distribution, internal consistency, factor analysis and expert opinion. Construct and convergent validity were evaluated using: Glucose Monitoring Satisfaction Scale, Diabetes Self-Management Questionnaire, Diabetes Distress Scale, WHO-5 Well-Being Index, and the Centre for Epidemiology Depression scale. Test-retest reliability was determined on 130 participants.

RESULTS: Internal consistency was high for all scales (α0.73 - 0.91), and test-retest reliability acceptable (ICC0.58 - 0.79 except for Device Characteristics). Construct and convergent validity indices were acceptable, with substantial overlap between the IGMSS and CGM satisfaction, self-management behaviours and emotional functioning. Based on expert review, items were written to be completed by those using SMBG or CGM.

CONCLUSIONS: The IGMSS has positive psychometric characteristics with scores reflecting capability (personalized knowledge, improved health), opportunity (relationships and device characteristics) and motivation.