A Digital Health Intervention to Lower Cardiovascular Risk: A Randomized Clinical Trial.

Importance: South Asian individuals have a high burden of premature myocardial infarction (MI).

Objectives: To test whether a digital health intervention (DHI) designed to change diet and physical activity improves MI risk among a South Asian population.

Design, Setting, And Participants: This single-blind, community-based, randomized clinical trial with 1-year follow-up was performed among South Asian men and women 30 years or older and living in Ontario and British Columbia who were free of cardiovascular disease. Data analysis was by intention to treat. Data were collected from June 3, 2012, to October 27, 2013. Final follow-up was completed on December 2, 2014, and data were analyzed from April 2, 2015, to February 29, 2016.

Interventions: Participants were randomized 1:1 to the DHI or control condition. The goal-setting DHI used emails or text messages and focused on improving diet and physical activity that was tailored to the participant's self-reported stage of change.

Main Outcomes And Measures: The change in an MI risk score from baseline to 1 year was the primary outcome. Secondary outcomes included the change in each objectively measured component of the MI risk score (ie, blood pressure, waist to hip ratio, hemoglobin A1c level, and the ratio of apolipoprotein B to apolipoprotein A). Genetic risk for MI was determined by counting the 9p21 risk alleles; results were provided to each participant at baseline.

Results: A total of 343 South Asian men and women (178 men [51.9%]; mean [SD] age, 50.6 [11.4] years) who were free of cardiovascular disease were randomized to the control condition (n = 174) or the DHI (n = 169). The mean (SD) MI risk score was 13.3 (6.6) at baseline. No significant difference was found in the change in MI score after 1 year between the DHI and control groups (-0.27; 95% CI, -1.12 to 0.58; P = .53) after adjusting for baseline scores, and no difference was found in the fully adjusted model (-0.39; 95% CI, -1.24 to 0.45; P = .36). No association between knowledge of the genetic risk status at baseline and the change in MI risk score was found (0.19; 95% CI, -0.40 to 0.78; P = .53).

Conclusions And Relevance: Among South Asian individuals, a DHI was not associated with a reduction in MI risk score after 12 months and was not influenced by knowledge of genetic risk status.

Trial Registration: clinicaltrials.gov Identifier: NCT01841398.