Risk of Major Adverse Cardiovascular Events After Emergency Department Visits for Hypertensive Urgency

BACKGROUND: Chronic hypertension is an established long-term risk factor for major adverse cardiovascular events (MACEs). However, little is known about short-term MACE risk after hypertensive urgency, defined as an episode of acute severe hypertension without evidence of target-organ damage. We sought to evaluate the short-term risk of MACE after an emergency department (ED) visit for hypertensive urgency resulting in discharge to home. METHODS: We performed a case-crossover study using deidentified administrative claims data. Our case periods were 1-week intervals from 0 to 12 weeks before hospitalization for MACE. We compared ED visits for hypertensive urgency during these case periods versus equivalent control periods 1 year earlier. Hypertensive urgency and MACE components were all ascertained using previously validated International Classification of Diseases , Tenth Revision Clinical Modification codes. We used McNemar test for matched data to calculate risk ratios. RESULTS: Among 2 225 722 patients with MACE, 1 893 401 (85.1%) had a prior diagnosis of hypertension. There were 4644 (0.2%) patients who had at least 1 ED visit for hypertensive urgency during the 12 weeks preceding their MACE hospitalization. An ED visit for hypertensive urgency was significantly more common in the first week before MACE compared with the same chronological week 1 year earlier (risk ratio, 3.5 [95% CI, 2.9–4.2]). The association between hypertensive urgency and MACE decreased in magnitude with increasing temporal distance from MACE and was no longer significant by 11 weeks before MACE (risk ratio, 1.2 [95% CI, 0.99–1.6]). CONCLUSIONS: ED visits for hypertensive urgency were associated with a substantially increased short-term risk of subsequent MACE.