Ischemic Stroke After Emergency Department Discharge for Symptoms of Transient Neurological Attack

Risk of Stroke After Posterior Reversible Encephalopathy Syndrome

BACKGROUND

Posterior reversible encephalopathy syndrome (PRES) can cause short-term cerebrovascular complications, such as brain infarction and hemorrhage. We hypothesized that PRES is also associated with an increased long-term risk of stroke.

METHODS

We performed a retrospective cohort study in the United States using statewide all-payer claims data from 2016 to 2018 on all admissions to nonfederal hospitals in 11 states. Adults with PRES were compared with adults with renal colic (negative control) and transient ischemic attack (TIA; positive control). Any stroke and the secondary outcomes of ischemic and hemorrhagic stroke were ascertained using International Classification of Diseases, Tenth Revision, Clinical Modification codes. We excluded prevalent stroke. We used time-to-event statistics to calculate incidence rates and Cox proportional hazards analyses to evaluate the association between PRES and stroke, adjusting for demographics and stroke risk factors. In a sensitivity analysis, outcomes within 2 weeks of index admission were excluded.

RESULTS

We identified 1606 patients with PRES, 1192 with renal colic, and 38 216 with TIA. Patients with PRES had a mean age of 56±17 years; 72% were women. Over a median follow-up of 0.9 years, the stroke incidence per 100 person-years was 6.1 (95% CI, 5.0-7.4) after PRES, 1.0 (95% CI, 0.62-1.8) after renal colic, and 9.7 (95% CI, 9.4-10.0) after TIA. After statistical adjustment for patient characteristics and risk factors, patients with PRES had an elevated risk of stroke compared with renal colic (hazard ratio [HR], 2.3 [95% CI, 1.7-3.0]), but lower risk than patients with TIA (HR, 0.67 [95% CI, 0.54-0.82]). In secondary analyses, compared with TIA, PRES was associated with hemorrhagic stroke (HR, 2.0 [95% CI, 1.4-2.9]). PRES was associated with ischemic stroke when compared with renal colic (HR, 1.9 [95% CI, 1.4-2.7]) but not when compared with TIA (HR, 0.49 [95% CI, 0.38-0.63]). Results were similar with 2-week washout.

CONCLUSIONS

Patients with PRES had an elevated risk of incident stroke.

Cost-Effectiveness of Advanced Neuroimaging for Transient and Minor Neurological Events in the Emergency Department

Background Accurate diagnosis of patients with transient or minor neurological events can be challenging. Recent studies suggest that advanced neuroimaging can improve diagnostic accuracy in low-risk patients with transient or minor neurological symptoms, but a cost-effective emergency department diagnostic evaluation strategy remains uncertain. Methods and Results We constructed a decision-analytic model to evaluate 2 diagnostic evaluation strategies for patients with low-risk transient or minor neurological symptoms: (1) obtain advanced neuroimaging (magnetic resonance imaging brain and magnetic resonance angiography head and neck) on every patient or (2) current emergency department standard-of-care clinical evaluation with basic neuroimaging. Main probability variables were: proportion of patients with true ischemic events, strategy specificity and sensitivity, and recurrent stroke rate. Direct healthcare costs were included. We calculated incremental cost-effectiveness ratios, conducted sensitivity analyses, and evaluated various diagnostic test parameters primarily using a 1-year time horizon. Cost-effectiveness standards would be met if the incremental cost-effectiveness ratio was less than willingness to pay. We defined willingness to pay as $100 000 US dollars per quality-adjusted life year. Our primary and sensitivity analyses found that the advanced neuroimaging strategy was more cost-effective than emergency department standard of care. The incremental effectiveness of the advanced neuroimaging strategy was slightly less than the standard-of-care strategy, but the standard-of-care strategy was more costly. Potentially superior diagnostic approaches to the modeled advanced neuroimaging strategy would have to be >92% specific, >70% sensitive, and cost less than or equal to standard-of-care strategy's cost. Conclusions Obtaining advanced neuroimaging on emergency department patient with low-risk transient or minor neurological symptoms was the more cost-effective strategy in our model.

Risk of stroke after emergency department visits for neurologic complaints

Objective

To assess the risk of subsequent stroke among older patients discharged from an emergency department (ED) without a diagnosis of TIA or stroke.

Methods

Using electronic health record data from a large urban, university hospital and a community-based hospital, we analyzed patients aged 60-89 years discharged to home from the ED without an International Statistical Classification of Diseases and Related Health Problems, 9th or 10th Revision diagnosis of TIA or stroke. Based on the presence/absence of a head CT and the presence/absence of a chief complaint suggestive of TIA or stroke ("symptoms") during the index ED visit, we created 4 mutually exclusive groups (group 1, reference: head CT no, symptoms no; group 2: head CT no, symptoms yes; group 3: head CT yes, symptoms no; and group 4: head CT yes, symptoms yes). We calculated rates of stroke in the 30, 90, and 365 days after the index visit and used multivariable logistic regression to estimate odds ratios (ORs) for subsequent stroke.

Results

Among 35,622 patients (mean age 70 years, 59% women, and 16% African American), unadjusted rates of stroke in 365 days were as follows: group 4: 2.5%; group 3: 1.1%; group 2: 0.69%; and group 1: 0.54%. The adjusted OR for stroke was 3.30 (95% confidence interval [CI], 1.61-6.76) in group 4, 1.56 (95% CI, 1.16-2.09) in group 3, and 0.61 (95% CI, 0.22-1.67) in group 2.

Conclusions

Among patients discharged from the ED without a diagnosis of TIA or stroke, the occurrence of a head CT and/or specific neurologic symptoms established a clinically meaningful risk gradient for subsequent stroke.