Promoting Self-Management in Adults with Type 2 Diabetes: Development of the Impact of Glucose Monitoring on Self-Management Scale

Objectives: Type 2 diabetes (T2D) management requires behavioural engagement to achieve optimal outcomes and continuous glucose monitoring (CGM) technologies may facilitate self-management. In this study we describe the development and validation of a self-report instrument, the Impact of Glucose Monitoring on Self-Management Scale (IGMSS), assessing the impact of device use (primarily CGM but also self-monitored blood glucose SMBG) on the capability, motivation, and opportunity to engage in self-management. Methods: Potential items were generated from 3 sources: themes and quotes from 13 adults with T2D motivated by CGM use who participated in a qualitative study; behaviour change theory identifying capability, opportunity, and motivation to self-manage; and expert committee review of items. An initial pool of 42 items were generated describing CGM as promoting personalized knowledge, improved health (Capability), improved relationships, having positive device characteristics (Opportunity), and improved engagement in self-management (Motivation). Based on expert committee consensus, items were written so as to be completed by those using any glucose-sensing device (SMBG and CGM). Psychometric evaluation was conducted with 514 English-speaking Canadians. Scale reduction (22 final items) was completed using item-response distribution, internal consistency, factor analysis, and expert opinion. Construct and convergent validity were evaluated using the Impact of Glucose Monitoring Satisfaction Scale, the Diabetes Self-Management Questionnaire, the Diabetes Distress Scale, the 5-item World Health Organization Well-Being Index, and the Centre for Epidemiology Depression Scale. Test–retest reliability was determined for 130 participants. Results: Internal consistency was high for all scales, ranging from 0.73 to 0.91. Test–retest reliability ranged from 0.58 to 0.79, except for Device Characteristics. Construct and convergent validity indices were acceptable. There was substantial overlap between the IGMSS and established measures of CGM satisfaction. IGMSS findings were also predictive of self-management behaviour and emotional functioning. Conclusions: The IGMSS has positive psychometric characteristics and has the potential to screen people with T2D for engagement in diabetes self-management using CGM or any sensing device. Scores can be determined for various aspects of Capability (Personalized Knowledge, Improved Health), Opportunity (Relationships and Device Characteristics), and Motivation.