Background: Hypertension-related visits to the emergency department (ED) are increasing every year. Thus, ED could play a significant role in detecting hypertension and providing necessary interventions. However, it is not known whether a hypertensive event observed in the ED is an independent risk factor for future major adverse cardiovascular events (MACE).
Methods: A population-based observational study was conducted using a nationally representative cohort that contained the claim data of 1 million individuals from 2002 to 2013. We included non-critical ED visits without any history of MACE, and compared the new occurrences of MACE according to the presence of hypertensive events using extended Cox regression model. The disease-modifying effect of a follow-up visit was assessed by analyzing the interaction between hypertensive event and follow-up visit.
Results: Among 262,927 first non-critical ED visits during the study period (from 2004 to 2013), 6,243 (2.4%) visits were accompanied by a hypertensive event. The hypertensive event group had a higher risk of having a first MACE at 3 pre-specified intervals: 0-3 years (HR, 4.25; 95% CI, 3.83-4.71; P<0.001), 4-6 years (HR, 3.65; 95% CI, 3.14-4.24; P<0.001), and 7-10 years (HR, 3.20; 95% CI, 2.50-4.11; P<0.001). Follow-up visits showed significant disease-modifying effect at 2 intervals: 0-3 years (HR 0.65, 95% CI, 0.50-0.83) and 4-7 years (HR 0.68, 95% CI, 0.48-0.95).
Conclusions: A hypertensive event in the ED is an independent risk factor for MACE, and follow-up visits after the event can significantly modify the risk.