A novel psychological-behavioral intervention to promote physical activity in type 2 diabetes.

Among the 30 million Americans with type 2 diabetes (T2D), physical activity is prospectively associated with better glycemic control, reduced cardiovascular risk, and lower rates of death. Unfortunately, more than 75% of T2D patients do not engage in recommended levels of physical activity. Many existing physical activity interventions in T2D have had limited effects on activity and diabetes outcomes, and most do not address psychological factors independently linked with greater activity. Furthermore, physical activity interventions that do appear to be effective are intensive and have been difficult to implement in clinical settings. Innovative, accessible interventions to promote physical activity in T2D are badly needed. Positive psychology (PP) interventions may represent a novel, effective component of a T2D activity intervention. Positive psychological well-being (e.g., optimism, positive affect) is prospectively associated with more physical activity, better glycemic control, and lower cardiac risk. PP interventions use simple exercises (e.g., using personal strengths, accessing gratitude) to systematically cultivate such well-being. In preliminary work, PP has led to substantial increases in activity when combined with existing behavior change programs. Motivational interviewing (MI) could be another element of a scalable activity intervention in T2D. MI is a well-established, effective approach to behavior change that can be delivered remotely. However, MI alone has had somewhat modest effects on activity in T2D, potentially due to low levels of optimism and self-efficacy in this population that could be addressed by PP. Given their complementary approaches to behavior change, PP and MI could be combined to promote optimism, self-efficacy, and motivation to engage in physical activity. We have developed a remotely delivered, combined PP-MI intervention to promote physical activity in T2D patients, and in an NIDDK R21 pilot trial (NIH Stage IB; N=60) we found the intervention to be well- accepted and associated with promising improvements in well-being and physical activity. We now aim to examine the efficacy of the 16-week PP-MI intervention, with 8 weeks of phone sessions and 16 total weeks of text messaging to further support change, in a randomized NIH Stage II efficacy trial in 280 patients with T2D and low baseline physical activity. PP-MI will be compared to a time-matched, MI-alone control condition. The primary study outcome will be improvement in moderate to vigorous physical activity (MVPA) at 16 weeks. We will also measure the intervention’s impact on overall physical activity, psychological measures, diabetes self- care, function, cardiac risk factors, and glycemic control at 8, 16, 24, and 52 weeks. Finally, we will assess PP- MI’s mechanism of effect on MVPA via causal mediation analyses to allow further intervention refinement. Through its potential to promote physical activity in T2D, the remotely delivered PP-MI program could impact public health and clinical practice. If PP-MI shows efficacy in this trial, we will more definitively examine its effects on glycemic control and cardiac risk in a larger, Stage III effectiveness-based trial.