Feasibility of Emergency Department-initiated, Mobile Health Blood Pressure Intervention: An Exploratory, Randomized Clinical Trial

Abstract

Objectives: We aimed to assess the feasibility of a text messaging intervention by determining the proportion of emergency department (ED) patients who responded to prompted home blood pressure (BP) self-monitoring and had persistent hypertension. We also explored the effect of the intervention on systolic blood pressure (sBP) over time.

Methods: We conducted a randomized, controlled trial of ED patients with expected discharge to home with elevated BP. Participants were identified by automated alerts from the electronic health record. Those who consented received a BP cuff to take home and enrolled in the 3-week screening phase. Text responders with persistent hypertension were randomized to control or weekly prompted BP self-monitoring and healthy behavior text messages.

Results: Among the 104 patients enrolled in the ED, 73 reported at least one home BP over the 3-week run-in (screening) period. A total of 55 of 73 reported a home BP of ≥140/90 and were randomized to SMS intervention (n = 28) or control (n = 27). The intervention group had significant sBP reduction over time with a mean drop of 9.1 mm Hg (95% confidence interval = 1.1 to 17.6).

Conclusions: The identification of ED patients with persistent hypertension using home BP self-monitoring and text messaging was feasible. The intervention was associated with a decrease in sBP likely to be clinically meaningful. Future studies are needed to further refine this approach and determine its efficacy.

Trial registration: ClinicalTrials.gov NCT02301455.

Figure 1:

Overview of Study Design

Figure 2:

Participant Screening and Flow

Figure 3:. Distribution of BP responses in the intervention group

Within the intervention group, the number of weeks that a blood pressure was texted back in response to the system prompt.

Figure 4:. Blood Pressure Trends and Early Drop-out Over Study Period

Each of the 104 patients grouped from left to right by those who did not qualify for randomization, the intervention group and the control group. Within each group participants are arranged from left to right in order of highest ED SBP. Red bars depict the change in SBP from ED visit to median screening phase SBP for patients taking BP medications; the blue bars represent this change for patients not taking BP medications. For patients who never returned any texts, the circles represent the ED SBP for patients taking BP medications and the triangles represent each subject who was not taking BP medications. The narrower, yellow bars represent the change in SBP from the screening phase to the final visit for the intervention group. Subject 73 is an example of a case where the SBP was higher at the final visit. The narrower, purple bars represent the change from screening phase to end of study for the control group. Some subjects with median SBP lower than 140 from the screening phase depicted above were randomized. In one case, a participant had a diastolic BP over 90, in the other cases at least one SBP measurement was 140 or above.

Figure 5 –. All study blood pressures over time

All systolic blood pressures, by week of study. Week 1 is the baseline in the emergency department, Weeks 2-4 are the screening period, Weeks 5-16 are weekly text messaging-based responses in the intervention group, and Week 17 is the final in-person follow up visit. Patients who were not eligible (due to SBP under 140) or did not respond to texts are indicated with a plus sign, the intervention group is indicated with triangles, and the control group with circles.