Effects of a Digital Intervention to Improve DASH and Blood Pressure Among US Adults.

Background: Dietary Approaches to Stop Hypertension (DASH) is a recommended first-line treatment for adults with hypertension, yet adherence to DASH is low. To evaluate the efficacy of a digital health intervention (DHI), compared with attention control, on changes in DASH adherence and blood pressure among adults with hypertension.

Methods: Nourish was a 12-month, parallel, 2-arm, randomized controlled trial of a virtually delivered DHI. Participants had a previous diagnosis of hypertension. The primary outcome was a 6-month change in DASH adherence. The secondary outcome was a change in blood pressure. We used linear mixed models to compare 6 and 12-month changes in DASH adherence, systolic blood pressure, and diastolic blood pressure.

Results: Nourish randomized 301 adults who averaged 54.4 (SD, 13.4) years and predominately identified as female (65%), White (53%), or Black (31%). Adjusted mean baseline DASH score was 2.30 (95% CI, 2.03-2.58). The adjusted mean baseline systolic blood pressure and diastolic blood pressure were 123.2 (95% CI, 119.5-126.9) and 77.1 (95% CI, 74.6-79.6) mm Hg. DASH score change was not significantly different between arms at 6 months (M_diff, 0.02 [95% CI, -0.37 to 0.40]). Yet, DHI participants had significantly greater 12-month changes in DASH score, relative to control (M_diff, 0.62 [95% CI, 0.16-1.08]). Between-group differences in 6-month changes were insignificant for systolic blood pressure and marginally significant for diastolic blood pressure, despite the DHI group showing significant blood pressure reductions from baseline.

Conclusions: A DHI led to modest improvements in DASH and blood pressure among adults with hypertension but did not outperform the attention control. Further research is needed to understand the utility of DHIs to promote DASH and identify intervention components that support long-term behavior change.