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.