Background: Enhancing self-management in health care through digital tools is a promising strategy to empower patients with type 2 diabetes (T2D) to improve self-care. Objective: This study evaluates whether the Greenhabit (mobile health [mHealth]) behavioral treatment enhances T2D outcomes compared with standard care. Methods: A 12-week, parallel, single-blind randomized controlled trial was conducted with 123 participants (62/123, 50%, female; mean age 58.25 years, SD 9.46 years) recently diagnosed with T2D. Participants were recruited face-to-face from primary care centers in Barcelona, Spain, between July 2021 and March 2022. They were randomly assigned to 1 of 2 groups: (1) an intervention group (n=61) instructed to use the Greenhabit mobile app alongside standard care, or (2) a control group (n=62) who received advice on maintaining a healthy diet and followed standard care. The Greenhabit app incorporates serious gaming technology. Participants received daily messages and challenges focused on promoting a healthy lifestyle, including nutrition, exercise, relaxation, a positive mindset, and a supportive social environment. The app encouraged participants to set weekly goals and awarded points for completing challenges. Data on nutrition, anthropometrics, and blood and urine samples were collected at baseline, 6 weeks, and 12 weeks. Questionnaires assessing quality of life, work-life balance, and social environment were administered at baseline and during the final visit. The primary outcomes were HbA1c and fasting plasma glucose (FPG). Repeated-measures analysis of variance was used to compare changes over time (baseline to 6 weeks and baseline to 12 weeks) between the 2 intervention groups. Analysis of covariance was performed to evaluate changes at 6 and 12 weeks, adjusted for baseline levels of each variable. Multiple contrasts were corrected using a Bonferroni post hoc test. Results: Both groups showed significant reductions in HbA1c after 6 and 12 weeks (mean change in the intervention group [n=50] -0.4%, P<.001 vs -0.3% in the control group [n=53], P=.001) and in FPG after 6 weeks (mean change in the intervention group -5.3 mg/dL, P=.01 vs control group -5.8 mg/dL, P=.01). At 12 weeks, the intervention group also showed significant reductions in systolic and diastolic blood pressures (mean change -4.5, P=.049 and -2.4 mmHg, P=.03, respectively), body weight (mean change -0.8 kg, P=.03), BMI (mean change -0.3 kg/m2, P=.03), waist circumference (mean change -1.0 cm, P=.046), and triglyceride concentration (mean change -20.0 mg/dL, P=.03). There was also a significant increase in high-density lipoprotein-cholesterol concentrations (mean change 2 mg/dL, P=.049). Finally, improvements were noted in 3 out of the 5 elements of balance: positivity, social environment, and work-life balance. Conclusions: The 12-week intervention with the Greenhabit behavioral treatment mHealth app showed beneficial effects on T2D outcomes and reduced the burden of cardiovascular risk factors. Although larger studies are warranted, these results suggest that mHealth apps can be a promising tool for improving T2D self-management.
