GMV Intervention involved 90-minute monthly sessions over 9 months, involving 6-10 participants, co-facilitated by a primary care physician and health educator.

The Patient Self-Management Scale was derived from a questionnaire used in the Diabetes Quality Improvement Project. The scale is designed to reflect patients' assessment of their ability to manage aspects of diabetes self-care in 5 separate areas (medication, diet, exercise, blood glucose monitoring, and foot care). Respondents are asked how difficult over the past year has it been to follow exactly as their doctor who takes care of their diabetes suggested. Possible scores for each scale item range from 0 to 100 with higher score indicating more self-efficacy. Total scale score is calculated as the average across all items. Change is calculated as 1-year score minus baseline score.

The Interpersonal Processes of Care (IPC) captures patient reports of providers' communication over the prior year. The scale is intended to measure patients' assessment of providers' communication within 3 broad domains: communication (e.g., lack of clarity), decision making (e.g., patient-centered decision making), and interpersonal style (e.g., friendliness). Each instrument item is scored on a 5-point scale ranging from 1 to 5. Scores are transformed to a 100-point scale and averaged across all items to create a total scale score. Higher total scores indicate better communication. Change is calculated as 1-year score minus baseline score.

The SF-12 Health Survey (SF-12) is a 12-item short-form survey used to measure health status and monitor health outcomes. The survey asks about various health aspects, including physical functioning, role limitations due to physical health problems, bodily pain, general health, vitality, social functioning, role limitations due to emotional problems, and mental health (psychological distress and psychological well-being). Two summary measures are derived: the Physical and the Mental Health Component Summary. For each component summary, survey items were weighted and summed to create a summary score between 0 and 100 with higher score indicating better functioning and outcome. Change is calculated as 1-year score minus baseline score.

The SF-12 Health Survey (SF-12) is a 12-item short-form survey used to measure health status and monitor health outcomes. The survey asks about various health aspects, including physical functioning, role limitations due to physical health problems, bodily pain, general health, vitality, social functioning, role limitations due to emotional problems, and mental health (psychological distress and psychological well-being). Two summary measures are derived: the Physical and the Mental Health Component Summary. For each component summary, survey items were weighted and summed to create a summary score between 0 and 100 with higher score indicating better functioning and outcome. Change is calculated as 1-year score minus baseline score.

A measure of patients' functional status is ascertained by asking patients the following question: "In the last 30 days, how many days did your health keep you in bed all or most of the day?" Number of days may range from 0 to 30, with lower number of days indicating better functional status.

A measure of diabetes interference on patients is ascertained by asking patients the following question: "In the last 12 months, how often has your diabetes kept you from doing your normal daily activities, such as going to work, grocery shopping, and taking care of yourself and others?" Responses consist of 6 possible options: "Always", "Almost Always", "Often", "Sometimes", "Almost Never", and "Never". These responses are grouped into 2 categories, with one category consisting of "Always", "Almost Always", and "Often" responses while the other category consists of the remaining responses. The proportion of patients reporting diabetes interference is the number of patients in the first category divided by the number of patients in the 2 categories combined.

Hemoglobin A1c is a form of hemoglobin that is measured primarily to identify the average plasma glucose concentration over prolonged periods of time. As the average amount of plasma glucose increases, the fraction of hemoglobin A1c increases in a predictable way. This serves as a marker for average blood glucose levels over the previous months prior to the measurement. Higher amounts of hemoglobin A1c indicate poorer control of blood glucose levels and have been associated with cardiovascular disease. Change is calculated as 1-year level minus baseline level.

Systolic blood pressure is the pressure exerted on arteries and vessels by the heart when it contracts and pushes blood through the arteries to the rest of the body. Change is calculated as 1-year pressure minus baseline pressure.

Diastolic blood pressure is the pressure exerted on the walls of the arteries and vessels in between heart beats, when the heart is relaxed and dilated, filling with blood. Change is calculated as 1-year pressure minus baseline pressure.

Body Mass Index (BMI) is a number calculated from a person's weight and height. BMI is defined as the individual's body mass divided by the square of their height. The formulae used produce a unit of measure of kg/m2. BMI provides an indicator of body fatness.