Abstract WP70: Emergency Department Visits For Hypertensive Urgency And Risk Of Subsequent Stroke

Introduction: Chronic hypertension is an established long-term risk factor for stroke. However, little is known about short-term stroke risk after an episode of acute severe hypertension without evidence of target organ damage (i.e., hypertensive urgency [HU]). We evaluated the short-term risk of stroke after an ED visit with HU resulting in discharge home (treat-and-release). Methods: We performed a case-crossover study using deidentified administrative claims from all nonfederal EDs and hospitals across 11 states. The study cohort comprised patients diagnosed with any stroke (ischemic stroke, intracerebral hemorrhage, or subarachnoid hemorrhage), defined using validated ICD-10 codes, between 2016-2018. We tabulated and compared incident ED visits for HU during case periods (2-week intervals from 0-24 weeks before the index stroke) to control periods (equivalent time periods exactly 1 year earlier). ED visits with HU were ascertained using the ICD-10 code I16.0, which we validated through detailed chart review of 50 patients at our center resulting in a code sensitivity and specificity of 100% and 96%, respectively. We used McNemar’s test for matched data to calculate risk ratios (RRs) for an ED HU visit occurring before stroke. Results: Among 45,063 patients with stroke, 22,417 (50%) were female and 37,577 (83%) had a prior diagnosis of hypertension. There were 201 patients with stroke who had at least one ED visit for HU during the preceding 24 weeks. An ED visit for HU was significantly more common in the 2 weeks before stroke compared to the 2-week control period 1 year earlier (RR, 5.1; 95% CI, 2.4-12.7; p<0.0001). The association between stroke and preceding ED visit for HU decreased in magnitude with increasing temporal distance from stroke and was no longer significant by the 7-8 week period before stroke (Figure 1). Conclusion: Treat-and-release ED visits for HU are associated with a significantly increased short-term risk of stroke.