A Psychological-behavioral Intervention for Physical Activity in Type 2 Diabetes

The investigators will compare a combined positive psychology and motivational interviewing (PP-MI) intervention that is adapted for patients with T2D to a motivational interviewing (MI) health education intervention. The MGH Diabetes Center and MGH primary care clinics will serve as the source of subjects for the study, with patients who have a diagnosis of T2D serving as potential participants. The investigators will enroll 60 participants, who will be randomized to either an 8-week PP-MI health behavior intervention or an 8-week MI-based health education intervention. In this project, the investigators plan to do the following: 1. Examine the feasibility and acceptability of an 8-week, telephone-delivered health behavior intervention utilizing PP exercises and MI with systematic goal-setting. 2. Determine whether the PP-MI intervention leads to greater increases in physical activity than the MI-based education intervention in T2D patients. 3. Explore the impact of the PP-MI intervention on other psychological, behavioral, and medical outcomes, compared to the MI-based education intervention. Participants will undergo an initial screening visit during which they will meet with study staff in person. At this visit, study eligibility will be confirmed, and eligible and willing participants will be enrolled. Following enrollment, participants will complete self-report measures, and vital signs and A1c will be measured. They then will take home and wear an accelerometer for one week, to measure baseline physical activity. Baseline information about enrolled participants will be obtained from the patients, care providers, and the electronic medical record as required for characterization of the population. This information will include data regarding medical history (type 2 diabetes mellitus), current medical variables (conditions affecting physical activity), medications, and sociodemographic data (age, gender, race/ethnicity, living alone). Participants will undergo a second in-person visit once adequate baseline physical activity data has been obtained. In this visit, accelerometer data will be reviewed to ensure that adequate baseline activity was captured. If so, participants will be randomized to either the PP-MI or MI-based health education intervention, then begin the study intervention. During this second in-person visit, participants will receive either a PP-MI or MI-based health education treatment manual, depending on randomization. For the PP-MI intervention: For each session, a PP exercise will be described in the manual, with instructions and space to write about the exercise and its effects. Next, an MI section will outline specific MI-based topics (e.g., pros/cons, managing slips) and facilitate physical activity goal-setting. At subsequent sessions, participants will review the prior week's PP exercise and learn about a new exercise, then will review the prior week's physical activity goal and set a new one. For the MI-based health education intervention: Each week, participants will learn about a different health behavior topic related to diabetes health. They will also be introduced to motivational interviewing topics in concert with the health behavior education topics, including medication adherence, having a heart-healthy diet, and being physically active. Participants will complete the remaining sessions by phone approximately weekly over the next 8 weeks. Phone sessions will last approximately 30 minutes, with PP-MI and physical activity assignments completed between phone sessions. PP and MI components will be delivered step-wise within sessions (rather than intertwined) based on our experience, participant feedback, and pilot work. If a week is missed, the session will not be skipped, but rather the intervention will be completed sequentially (with participants who miss weeks then missing the final sessions), with the exception of the final call, which skips to Planning for the Future in all cases. Participants will undergo an in-person follow-up assessment at 8 weeks. At this session, participants will repeat self-report assessments that were administered at baseline. Vital signs and a blood sample will again be collected at this in-person visit. Prior to this assessment, participants will wear an accelerometer for an additional 7 days to measure physical activity. Participants will also undergo a phone follow-up assessment at 16 weeks. During this session over the phone, participants will repeat self-report assessments that were administered at baseline. Finally, prior to this follow-up, participants will wear another accelerometer for 7 days to measure physical activity.