In the recently published SAHARA study, researchers found that a digital health intervention using messaging targeted at lifestyle modification failed to reduce heart attack risk among South Asian adults.

While tremendous progress has been made in treatment of coronary artery disease, it’s now well recognized that we’ve fallen short in primary prevention. When working with a patient, primary prevention starts with understanding their risk. In the US, recent guidelines gave us a new risk estimator that the American College of Cardiology packaged into the ASCVD Risk Estimator app. Once you understand their risk, then comes the intervention focused on modifiable risk factors.

In the SAHARA study, researchers used a combination messaging platform that sent educational and motivational messages via email and text message. Motivational emails tailored to the participant’s stage of change went out every other week and health tips via text messaging went out weekly. They measured risk using the InterHeart Risk Score at the beginning and end of the study. This risk score incorporates a variety of parameters such as waist circumference, smoking, cholesterol, and many other modifiable risk factors.

They randomized nearly 350 patients to either the intervention or control. Overall, they found no difference between the two groups in terms of improvements in their risk scores (RR −0.27; 95% CI, −1.12 to 0.58; P = .53).

The SAHARA study is another important reminder that when it comes to digital health interventions, the “dose” matters. We’ve now seen a number of negative studies using low frequency interventions. In the much publicized Scripps study where patients were simply given a variety of digital health devices, the only intervention was giving the patient the device. In another heart failure trial, a similarly low frequency educational intervention failed to show benefit.

Other studies using high frequency interventions have been more positive. In an Australian study among patients with known coronary disease, reductions in a variety of risk factors such as blood pressure and cholesterol were achieved with high frequency educational text messaging. In the mActive study, giving patients a connected pedometer that generated adaptive text messaging to support physical activity led to significant improvements in step counts.

The core strength of digital health technology is that it can be with patients all the time, including in fleeting moments when critical decisions about whether to go exercise or watch TV, to smoke a cigarette or chew the gum, or to eat a salad or McDonalds are being made. This work joins a growing list of studies that can help guide design of more effective digital health interventions by fine tuning the “dose” of the intervention being delivered.