Abstract TP181: Prior Antiplatelet Use and Baseline Stroke Severity: A Population-Based Study

Introduction: There is conflicting evidence on the association of antiplatelet (AP) use prior to admission with baseline ischemic stroke (IS) severity. We evaluated this association within a large, bi-racial population.

Methods: We identified all hospital-ascertained cases of IS that occurred in 2010 (including ED arriving, direct admits, and in-hospital strokes) within a population of 1.3 million. Specific AP used prior to presentation for IS were aspirin, clopidogrel, dipyridamole, prasugrel, and cilostazol. We excluded those on an anticoagulant (AC) medication for this analysis. Baseline IS severity was defined as NIH stroke scale score (NIHSS) on admission. A multivariable linear regression model including demographic and clinical variables with log-transformed NIHSS as the dependent variable was used to evaluate the effect of prior AP use on stroke severity (results shown as percentage change in NIHSS).

Results: In 2010, there were 2259 IS cases, of which 1982 (22% black, 55% female, median age 70 years [58, 81]) were included in the analysis, and 998 (50%) had history of prior AP use. Unadjusted, minor stroke (NIHSS ≤5) was slightly less common in those with prior AP use compared with those without (68% vs. 72%; p=0.04). In the multivariable model among patients with history of atrial fibrillation (AF) yet not on AC, a significant 23% reduction in NIHSS (average NIHSS 6.00 to 4.88, p=0.02) was seen in those with prior AP use. No such association was found in patients with no history of AF. The table displays the multivariable model of stroke severity.

Conclusion: We found that prior AP use did not have significant association with baseline stroke severity in the multivariable analysis. However, a subgroup of patients with history of AF had significantly less severe strokes with prior antiplatelet use.

Abstract WMP55: Temporal Trends of Sex Differences in Transient Ischemic Attack Incidence Within a Population

Introduction: Previously we reported that ischemic stroke incidence is declining over time for men but not women. We sought to describe temporal trends of sex differences in TIA incidence within a large, biracial population.

Methods: Among the biracial population of 1.3 million in the Greater Cincinnati Northern Kentucky Stroke Study (GCNKSS) region, all first-ever transient ischemic attacks (TIAs) among area residents (≥20 years old) were identified at all local hospitals. Out of hospital cases were ascertained using a sampling scheme. All cases were reviewed by study physicians. Sex-specific TIA incidence rates over time (during 7/93-6/94 and calendar years 1999, 2005, and 2010) were determined. Incidence rates were calculated using the age-, race-, and sex-specific number of TIAs divided by the population in that group; rates were standardized to the 2010 U.S. population. Statistical testing for differences over time was done using linear regression models adjusted for age and race. The delta method was used to estimate the ratio of female to male TIA incidence and the associated standard error (SE).

Results: There were a total of 3203 patients with incident TIA; 54% were female, and 12% were black. Overall, mean age for men was 66 (SE 0.36) compared to 71 (SE 0.33) for women, p=0.01. Compared with men, women had lower rates of TIA in all 4 study periods, and TIA incidence rates were stable over time for women (p=0.19) and men (p=0.12). (See table). TIA patients were younger in 2010 than in 1993/4 and 1999 (P<0.05) with means of 68 (SE 0.53), 70 (SE 0.50) and 71 (SE 0.47) respectively.

Conclusions: Within the GCNKSS population, women had lower TIA incidence rates than men. In contrast to what we have previously described in ischemic stroke incidence, neither the sex difference in incidence nor the sex-specific incidence rates are changing over time. Further research is needed to understand the drivers of higher TIA incidence in men and the lack of change in TIA incidence over time.

Systemic inflammatory response syndrome, infection, and outcome in intracerebral hemorrhage

Objective:

Systemic inflammatory response syndrome (SIRS) may be related to poor outcomes after intracerebral hemorrhage (ICH).

Methods:

The Ethnic/Racial Variations of Intracerebral Hemorrhage study is an observational study of ICH in whites, blacks, and Hispanics throughout the United Sates. SIRS was defined by standard criteria as 2 or more of the following on admission: (1) body temperature <36°C or >38°C, (2) heart rate >90 beats per minute, (3) respiratory rate >20 breaths per minute, or (4) white blood cell count <4,000/mm³ or >12,000/mm³. The relationship among SIRS, infection, and poor outcome (modified Rankin Scale [mRS] 3–6) at discharge and 3 months was assessed.

Results:

Of 2,441 patients included, 343 (14%) met SIRS criteria at admission. Patients with SIRS were younger (58.2 vs 62.7 years; p < 0.0001) and more likely to have intraventricular hemorrhage (IVH; 53.6% vs 36.7%; p < 0.0001), higher admission hematoma volume (25.4 vs 17.5 mL; p < 0.0001), and lower admission Glasgow Coma Scale (GCS; 10.7 vs 13.1; p < 0.0001). SIRS on admission was significantly related to infections during hospitalization (adjusted odds ratio [OR] 1.36, 95% confidence interval [CI] 1.04–1.78). In unadjusted analyses, SIRS was associated with poor outcomes at discharge (OR 1.96, 95% CI 1.42–2.70) and 3 months (OR 1.75, 95% CI 1.35–2.33) after ICH. In analyses adjusted for infection, age, IVH, hematoma location, admission GCS, and premorbid mRS, SIRS was no longer associated with poor outcomes.

Conclusions:

SIRS on admission is associated with ICH score on admission and infection, but it was not an independent predictor of poor functional outcomes after ICH.

Sex-specific stroke incidence over time in the Greater Cincinnati/Northern Kentucky Stroke Study

OBJECTIVE

Recent data suggest stroke incidence is decreasing over time, but it is unknown whether incidence is decreasing in women and men to the same extent.

METHODS

Within our population of 1.3 million, all incident strokes among residents ≥20 years old were ascertained at all hospitals during July 1993-June 1994 and calendar years 1999, 2005, and 2010. A sampling scheme was used to ascertain out-of-hospital cases. Sex-specific incidence rates per 100,000 among black and white participants, age- and race-adjusted, were standardized to the 2000 US Census population. Trends over time by sex were compared; a Bonferroni correction was applied for multiple comparisons.

RESULTS

Over the 4 study periods, there were 7,710 incident strokes; 57.2% (n = 4,412) were women. Women were older than men (mean ± SE 72.4 ± 0.34 vs 68.2 ± 0.32, p < 0.001). Incidence of all strokes decreased over time in men (263 [confidence interval 246-281] to 192 [179-205], p < 0.001) but not in women (217 [205-230] to 198 [187-210], p = 0.15). Similar sex differences were seen for ischemic stroke (men, 238 [223-257] to 165 [153-177], p < 0.01; women, 193 [181-205] to 173 [162-184], p = 0.09). Incidence of all strokes and of ischemic strokes was similar between women and men in 2010. Incidence of intracerebral hemorrhage and subarachnoid hemorrhage were stable over time in both sexes.

CONCLUSIONS

Decreases in stroke incidence over time are driven by a decrease in ischemic stroke in men. Contrary to previous study periods, stroke incidence rates were similar by sex in 2010. Future research is needed to understand why the decrease in ischemic stroke incidence is more pronounced in men.

Use of Statins and Outcomes in Intracerebral Hemorrhage Patients

BACKGROUND AND PURPOSE

Statin use may be associated with improved outcome in intracerebral hemorrhage patients. However, the topic remains controversial. Our analysis examined the effect of prior, continued, or new statin use on intracerebral hemorrhage outcomes using the ERICH (Ethnic/Racial Variations of Intracerebral Hemorrhage) data set.

METHODS

We analyzed ERICH (a multicenter study designed to examine ethnic variations in the risk, presentation, and outcomes of intracerebral hemorrhage) to explore the association of statin use and hematoma growth, mortality, and 3-month disability. We computed subset analyses with respect to 3 statin categories (prior, continued, or new use).

RESULTS

Two thousand four hundred and fifty-seven enrolled cases (mean age, 62 years; 42% females) had complete data on mortality and 3-month disability (modified Rankin Scale). Among those, 1093 cases were on statins (prior, n=268; continued, n=423; new, n=402). Overall, statin use was associated with reduced mortality and disability without any effect on hematoma growth. This association was primarily driven by continued/new statin use. A multivariate analysis adjusted for age and major predictors for poor outcome showed that continued/new statins users had good outcomes compared with prior users. However, statins may have been continued/started more frequently among less severe patients. When a propensity score was developed based on factors that could influence a physician's decision in prescribing statins and used as a covariate, continued/new statin use was no longer a significant predictor of good outcome.

CONCLUSIONS

Although statin use, especially continued/new use, was associated with improved intracerebral hemorrhage outcomes, this effect may merely reflect the physician's view of a patient's prognosis rather than a predictor of survival.

Assessment of the interaction of age and sex on 90-day outcome after intracerebral hemorrhage

OBJECTIVE

Because age affects hormonal production differently in women compared with men, we sought to define sex and age interactions across a multiracial/ethnic population after intracerebral hemorrhage (ICH) to uncover evidence that loss of gonadal hormone production would result in loss of the known neuroprotective effects of gonadal hormones.

METHODS

Clinical and radiographic data from participants in the Ethnic/Racial Variations of Intracerebral Hemorrhage study and the Genetic and Environmental Risk Factors for Hemorrhagic Stroke study prior to December 2013 were used. Relationships among sex, age, and outcome after ICH in 616 non-Hispanic black, 590 Hispanic, and 868 non-Hispanic white participants were evaluated using multivariable logistic regression analysis. Poor outcome was defined as modified Rankin Scale score ≥3 at 90 days after ICH.

RESULTS

Sex differences were found in multiple variables among the racial/ethnic groups, including age at onset, premorbid neurologic status, and neurologic outcome after ICH. Overall, no sex-age interaction effect was found for mortality (p = 0.183) or modified Rankin Scale score (p = 0.378) at 90 days after ICH. In racial/ethnic subgroups, only the non-Hispanic black cohort provided possible evidence of a sex-age interaction on 90-day modified Rankin Scale score (p = 0.003).

CONCLUSION

Unlike in ischemic stroke, there was no evidence that patient sex modified the effect of age on 90-day outcomes after ICH in a large multiracial/ethnic population. Future studies should evaluate biological reasons for these differences between stroke subtypes.

CLINICALTRIALSGOV IDENTIFIER

NCT01202864.

Estimated Impact of Emergency Medical Service Triage of Stroke Patients on Comprehensive Stroke Centers: An Urban Population-Based Study

BACKGROUND AND PURPOSE

The American Stroke Association recommends that Emergency Medical Service bypass acute stroke-ready hospital (ASRH)/primary stroke center (PSC) for comprehensive stroke centers (CSCs) when transporting appropriate stroke patients, if the additional travel time is ≤15 minutes. However, data on additional transport time and the effect on hospital census remain unknown.

METHODS

Stroke patients ≥20 years old who were transported from home to an ASRH/PSC or CSC via Emergency Medical Service in 2010 were identified in the Greater Cincinnati area population of 1.3 million. Addresses of all patients' residences and hospitals were geocoded, and estimated travel times were calculated. We estimated the mean differences between the travel time for patients taken to an ASRH/PSC and the theoretical time had they been transported directly to the region's CSC.

RESULTS

Of 929 patients with geocoded addresses, 806 were transported via Emergency Medical Service directly to an ASRH/PSC. Mean additional travel time of direct transport to the CSC, compared with transport to an ASRH/PSC, was 7.9±6.8 minutes; 85% would have ≤15 minutes added transport time. Triage of all stroke patients to the CSC would have added 727 patients to the CSC's census in 2010. Limiting triage to the CSC to patients with National Institutes of Health Stroke Scale score of ≥10 within 6 hours of onset would have added 116 patients (2.2 per week) to the CSC's annual census.

CONCLUSIONS

Emergency Medical Service triage to CSCs based on stroke severity and symptom duration may be feasible. The impact on stroke systems of care and patient outcomes remains to be determined and requires prospective evaluation.

Variability in the Use of Platelet Transfusion in Patients with Intracerebral Hemorrhage: Observations from the Ethnic/Racial Variations of Intracerebral Hemorrhage Study

BACKGROUND

We examined platelet transfusion (PTx) in the Ethnic/Racial Variations of Intracerebral Hemorrhage (ERICH) study, hypothesizing that rates of PTx would vary among hospitals and depend on whether patients were on an antiplatelet therapy or underwent intracerebral hemorrhage (ICH) surgical treatment.

METHODS

The ERICH study is a prospective observational study evaluating risk factors for ICH among whites, blacks, and Hispanics. We identified factors associated with PTx, examined practice patterns of PTx across the United States, and explored the association of PTx with mortality and poor outcome (modified Rankin Scale score 4-6).

RESULTS

Nineteen centers enrolled 2572 ICH cases; 11.7% received PTx. Factors significantly associated with PTx were antiplatelet use before onset (odds ratio [OR], 5.02; 95% confidence interval [CI], 3.81-6.61, P < .0001), thrombocytopenia (OR, 13.53; 95% CI, 8.43-21.72, P < .0001), and ventriculostomy placement (OR, 1.85; 95% CI, 1.36-2.52, P < .0001). Blacks were less likely (OR, .57; 95% CI, .41-0.80) to receive PTx. Among patients who received PTx, 42.4% were not on an antiplatelet therapy before onset. Twenty-three percent of patients on antiplatelet therapy received PTx, but percentages varied from 0% to 71% across centers. There was no difference in mortality or poor outcome at 3 months between patients receiving PTx and those who did not.

CONCLUSIONS

The frequency of PTx for ICH varies across academic centers. Thrombocytopenia, antiplatelet use, vascular risk factors, and ventriculostomy placement were associated with PTx. PTx was not associated with improved outcomes. We anticipate reduced PTx use over time given recent clinical trial data suggesting its use could be harmful; however, the issue of whether surgical management warrants PTx remains.

Aggressiveness of care following intracerebral hemorrhage in women and men

OBJECTIVE

To compare comorbidities and use of surgery and palliative care between men and women with intracerebral hemorrhage (ICH).

METHODS

The Ethnic/Racial Variations of Intracerebral Hemorrhage (ERICH) study is a prospective, multicenter, case-control study of ICH risk factors and outcomes. We compared comorbidities, treatments, and use of do-not-resuscitate (DNR) orders in men vs women. Multivariate analysis was used to assess the likelihood of ICH surgery and palliative care after adjustment for variables that were p < 0.1 in univariate analyses and backward elimination to retain those that were significant (p < 0.05).

RESULTS

Women were older on average (65.0 vs 59.9, p < 0.0001), and higher proportions of women had previous stroke (24.1% vs 19.3%, p = 0.002), had dementia (6.1% vs 3.4%, p = 0.0007), lived alone (23.1% vs 18.0%, p = 0.0005), and took anticoagulants (12.8% vs 10.1% p = 0.02), compared with men. Men had higher rates of alcohol and cocaine use. After adjusting for age, hematoma volume, and ICH location, there was no difference in rates of surgical treatment by sex (odds ratio [OR] 0.93 for men vs women, 95% confidence interval [CI] 0.68-1.28, p = 0.67), and there was no difference in DNR/comfort care decisions after adjustment for ICH score, prior stroke, and dementia (OR 0.96, CI 0.77-1.22, p = 0.76).

CONCLUSIONS

After ICH, women do not receive less aggressive care than men after controlling for the substantial comorbidity differences. Future studies on sex bias should include the presence of comorbidities, prestroke disability, and other factors that may influence management.

Practice Patterns for Acute Ischemic Stroke Workup: A Longitudinal Population-Based Study

Background

We examined practice patterns of inpatient testing to identify stroke etiologies and treatable risk factors for acute ischemic stroke recurrence.

Methods and Results

We identified stroke cases and related diagnostic testing from four 1‐year study periods (July 1993 to June 1994, 1999, 2005, and 2010) of the Greater Cincinnati/Northern Kentucky Stroke Study. Patients aged ≥18 years were included. We focused on evaluation of extracranial arteries for carotid stenosis and assessment of atrial fibrillation because randomized controlled trials supported treatment of these conditions for stroke prevention across all 4 study periods. In each study period, we also recorded stroke etiology, as determined by diagnostic testing and physician adjudication. An increasing proportion of stroke patients received assessment of both extracranial arteries and the heart over time (50%, 58%, 74%, and 78% in the 1993–1994, 1999, 2005, and 2010 periods, respectively; P<0.0001 for trend), with the most dramatic individual increases in echocardiography (57%, 63%, 77%, and 83%, respectively). Concurrently, we observed a decrease in strokes of unknown etiology (47%, 48%, 41%, and 38%, respectively; P<0.0001 for trend). We also found a significant increase in strokes of other known causes (32%, 25%, 45% and 59%, respectively; P<0.0001 for trend).

Conclusions

Stroke workup for treatable causes of stroke are being used more frequently over time, and this is associated with a decrease in cryptogenic strokes. Future study of whether better determination of treatable stroke etiologies translates to a decrease in stroke recurrence at the population level will be essential.

Alcohol use and risk of intracerebral hemorrhage

OBJECTIVE

To analyze the dose-risk relationship for alcohol consumption and intracerebral hemorrhage (ICH) in the Ethnic/Racial Variations of Intracerebral Hemorrhage (ERICH) study.

METHODS

ERICH is a multicenter, prospective, case-control study, designed to recruit 1,000 non-Hispanic white patients, 1,000 non-Hispanic black patients, and 1,000 Hispanic patients with ICH. Cases were matched 1:1 to ICH-free controls by age, sex, race/ethnicity, and geographic area. Comprehensive interviews included questions regarding alcohol consumption. Patterns of alcohol consumption were categorized as none, rare (<1 drink per month), moderate (≥1 drink per month and ≤2 drinks per day), intermediate (>2 drinks per day and <5 drinks per day), and heavy (≥5 drinks per day). ICH risk was calculated using the no-alcohol use category as the reference group.

RESULTS

Multivariable analyses demonstrated an ordinal trend for alcohol consumption: rare (odds ratio [OR] 0.57, p < 0.0001), moderate (OR 0.65, p < 0.0001), intermediate (OR 0.82, p = 0.2666), and heavy alcohol consumption (OR 1.77, p = 0.0003). Subgroup analyses demonstrated an association of rare and moderate alcohol consumption with decreased risk of both lobar and nonlobar ICH. Heavy alcohol consumption demonstrated a strong association with increased nonlobar ICH risk (OR 2.04, p = 0.0003). Heavy alcohol consumption was associated with significant increase in nonlobar ICH risk in black (OR 2.34, p = 0.0140) and Hispanic participants (OR 12.32, p < 0.0001). A similar association was not found in white participants.

CONCLUSIONS

This study demonstrated potential protective effects of rare and moderate alcohol consumption on ICH risk. Heavy alcohol consumption was associated with increased ICH risk. Race/ethnicity was a significant factor in alcohol-associated ICH risk; heavy alcohol consumption in black and Hispanic participants poses significant nonlobar ICH risk.

Prevalence of Positive Troponin and Echocardiogram Findings and Association With Mortality in Acute Ischemic Stroke

BACKGROUND AND PURPOSE

Acute ischemic stroke (AIS) patients may have raised serum cardiac troponin levels on admission, although it is unclear what prognostic implications this has, and whether elevated levels are associated with cardiac causes of stroke or structural cardiac disease as seen on echocardiogram. We investigated the positivity of cardiac troponin and echocardiogram testing within a large biracial AIS population and any association with poststroke mortality.

METHODS

Within a catchment area of 1.3 million, we screened emergency department admissions from 2010 using International Classification of Diseases, Ninth Edition, discharge codes 430 to 436 and ascertained all physician-confirmed AIS cases by retrospective chart review. Hypertroponinemia was defined as elevation in cardiac troponin above the standard 99th percentile. Multiple logistic regression was performed, controlling for stroke severity, history of cardiac disease, and all other stroke risk factors.

RESULTS

Of 1999 AIS cases, 1706 (85.3%) had a cardiac troponin drawn and 1590 (79.5%) had echocardiograms. Hypertroponinemia occurred in 353 of 1706 (20.7%) and 160 of 1590 (10.1%) had echocardiogram findings of interest. Among 1377 who had both tests performed, hypertroponinemia was independently associated with echocardiogram findings (odds ratio, 2.9; 95% confidence interval, 2-4.2). When concurrent myocardial infarctions (3.5%) were excluded, hypertroponinemia was also associated with increased mortality at 1 year (35%; odds ratio, 3.45; 95% confidence interval, 2.1-5.6) and 3 years (60%; odds ratio, 2.91; 95% confidence interval, 2.06-4.11).

CONCLUSIONS

Hypertroponinemia in the context of AIS without concurrent myocardial infarction was associated with structural cardiac disease and long-term mortality. Prospective studies are needed to determine whether further cardiac evaluation might improve the long-term mortality rates seen in this group.

Association Between Acute Kidney Disease and Intravenous Dye Administration in Patients With Acute Stroke: A Population-Based Study

BACKGROUND AND PURPOSE

Computed tomographic angiography and conventional angiography provide timely vascular anatomic information in patients with stroke. However, iodinated contrast dye may cause acute kidney injury (AKI). Within a large, biracial population, we examined in-hospital incidence of new or worsening kidney disease in patients with stroke and its association with administration of intravenous dye.

METHODS

All adult residents of the Greater Cincinnati/Northern Kentucky region with acute ischemic stroke or intracerebral hemorrhage who presented to an emergency department in 2010 were included. Prevalence of unsuspected kidney disease at the time of emergency department presentation and the incidence of AKI after admission in 2 groups of patients-those who did and those who did not receive intravenous dye-were determined.

RESULTS

In 2010, 2299 patients met inclusion criteria (89% ischemic stroke and 11% intracerebral hemorrhage); mean age 69 years (SD 15), 22% black, and 54% women. Among these patients, 37% had kidney disease at baseline, including 22% (516/2299) in whom this was unsuspected. Two percent (2%; 15/853) of patients with baseline kidney disease developed AKI during the hospital stay. Of those with no baseline kidney disease, 1% (14/14 467) developed AKI. There was no association between dye administration and new or worsening kidney disease.

CONCLUSIONS

Although 22% of patients in the Greater Cincinnati/Northern Kentucky stroke population had unsuspected kidney disease, the incidence of new or worsening kidney disease was low, and AKI was not associated with dye administration. These findings confirm single-center reports that the risk of severe renal complications after contrast dye is small.

Abstract TP170: Age and Race Disparities of Cardioembolic and Cryptogenic Strokes Over Time

Introduction: Cardioembolic (CE) stroke etiology has been increasing over time. How incidence rates of CE strokes within subgroups of the population have been changing is not known. We sought to determine if strokes of CE etiology have been changing similarly between races and between older versus younger populations over a recent 17-year period.

Methods: Within the Greater Cincinnati/Northern Kentucky (GCNK) catchment area of 1.3 million, all strokes were ascertained in the population from July 1993 to June 1994 and in 1999, 2005 and 2010 using ICD-9 codes 430-436. Stroke subtypes were determined by retrospective physician review and were then examined by age (< 50 or ≥ 50) and race (black or white). The proportions of incident stroke subtypes with 95% confidence intervals were calculated for each study period.

Results: There was an increase in the proportion of ischemic stokes identified as having CE etiology over time (p = 0.0002). The Table shows the percentage of CE and cryptogenic strokes by both race and age for each study period. Whites had a higher percentage of CE strokes compared with blacks, with the largest difference in 2010. The percentage of CE strokes in patients ≥50 years increased in 2010 but remained relatively stable in patients < 50 years old. Examination by race showed just over 10% reduction in cryptogenic strokes over time in both blacks and whites. The proportion of cryptogenic strokes decreased in both those ≥50 years and in those <50 years over time.

Conclusions: In our population, there was an increase in the proportion of CE strokes in whites only, most significantly between the two most recent study periods. Conversely, the percentage of cryptogenic strokes has decreased steadily over the study periods and equally in blacks and whites. Future studies are needed to explore the rates of longer-term cardiac monitoring to evaluate if this fully explains changes seen in CE stroke.

Abstract WP226: Isolated Aphasia in the Emergency Department: Prevalence and Characteristics of Isolated Aphasia Due to Stroke Within a Population

Background: Aphasia is a disabling consequence of ischemic stroke (IS), usually caused by strokes in the territory of the left middle cerebral artery. It is often seen as part of a larger syndrome with right hemiparesis and other left hemisphere signs. Isolated aphasia may be difficult to recognize given the lack of motor symptoms, potentially delaying treatment. Our study seeks to determine the prevalence of isolated aphasia, the rate at which these patients call 911, and the rate and speed of treatment with rt-PA compared with the general IS population.

Methods: Adult IS patients in 2005 and 2010 in the Greater Cincinnati/Northern KY region (pop. 1.3 million) were ascertained from all local hospitals via ICD-9 codes 430-436, using retrospective chart review. We limited analysis to acute IS cases that presented to an ED. Isolated aphasia was defined by a score >0 on item 9 of the initial rNIHSS (indicating language deficit) and scores of 0 on all other items except 1b and 1c. We compared rates of EMS use and rt-PA administration and median times to presentation and treatment for those with isolated aphasia versus not, using chi-square, Fisher’s exact test, t-test, or Wilcoxon rank-sum test.

Results: In 2005 and 2010, 3814 IS cases presented to EDs in the region; 22% were black, 56% were female, and the mean (SD) age was 70 (15) years. Of these, 120 (3.2%) presented with isolated aphasia. Characteristics of the isolated aphasia group are compared with all other IS in Table 1. Isolated aphasia patients showed a trend toward later arrival and lower rate of treatment with rt-PA.

Discussion: The trend toward later arrival in patients with isolated aphasia, though not statistically significant, suggests a need to better educate the public on recognizing this stroke syndrome. Isolated aphasia was significantly associated with atrial fibrillation and was associated with decreased small vessel and increased cardioembolic and undetermined stroke subtypes, a finding that merits further study.

Abstract TMP76: Stroke Quality-of-care Metrics in Comprehensive and Primary Stroke Centers and Non-stroke Centers

Introduction: Measuring the quality of stroke care has become increasingly important, but real-world data are limited, especially because many hospitals do not track their own statistics. We sought to determine differences in quality-of-care metrics for ischemic stroke (IS) among non-stroke centers, primary stroke centers (PSC), and comprehensive stroke centers (CSC).

Methods: The Greater Cincinnati/Northern Kentucky (GCNK) Stroke Study measures temporal trends in the incidence of stroke in a biracial population of 1.3 million. Adult IS cases in 2010 from the GCNK region were ascertained from all local hospitals via ICD-9 codes 430-436 using retrospective chart review. Hospitals included 10 non-stroke centers, 2 PSCs, and 1 PSC that earned CSC status in 2013. Differences in IS patients’ demographics, medical histories, and quality measures were evaluated among hospital categories using chi-square, Fisher’s exact, and Kruskal-Wallis tests. Quality measures were matched to Get With The Guidelines-Stroke (GWTG-S) when possible, although data regarding the appropriateness for non-treatment were not available.

Results: In 2010, there were 1,981 IS patients in our population (55% female, 21% black) with a median age of 71 years. Of these, 83 were transferred to a different hospital type. There were significant differences in the demographics and medical histories of IS patients, as well as the majority of quality measures, with the CSC and PSCs demonstrating greater compliance with most metrics. (Table)

Conclusions: We found significant hospital-level differences in both premorbid patient characteristics and quality-of-care metrics depending on the hospital stroke certification status. To our knowledge, this is the first measurement of best-practice care specifically involving hospitals not participating in national quality improvement programs, such as GWTG-S. These differences may help inform quality improvement efforts across hospital types.

Abstract 135: Towards Automated Incidence Rate Reporting: Leveraging Machine Learning Technologies to Assist Stroke Adjudication in a Large-scale Epidemiological Study

Introduction: Epidemiological studies utilizing administrative databases typically use International Classification of Diseases (ICD) codes to identify stroke cases and estimate incidence rates. However, they are limited by sensitivity/specificity across study designs and stroke types. Few studies utilize physician chart review of patient records to confirm cases for improved accuracy, as this is labor intensive. We sought to develop a machine learning (ML) approach that could adjudicate potential stroke events.

Methods: We utilized 8081 hospitalized stroke events in the Greater Cincinnati/Northern Kentucky Stroke Study. The study coordinators identified events with stroke-related diagnoses (ICD9 codes 430-438) from 17 regional hospitals in 2005 and 2010 and performed detailed chart abstraction. The information (e.g. diagnostic tests) was abstracted from patients’ medical records for each event, followed by physician case adjudication. Utilizing all clinical variables, a ML algorithm (logistic regression) was used to predict stroke cases and subtypes (ischemic, hemorrhagic, TIA, and non-strokes). Linear regression (LR) was applied to calibrate ML outputs and estimate prediction intervals based on gold-standard physician adjudication. The ML and LR models were trained on one year of data and tested on the other year. The model results were compared with using ICD-9 (ischemic: 434/436; hemorrhagic: 430-432; TIA: 435; non-stroke: other codes) calibrated by LR analysis.

Results: Prediction intervals generated by ML covered the majority of true numbers of stroke events (Table). Compared with ICD9 codes, the ML algorithm achieved better sensitivity/specificity and more “hits” with narrower prediction intervals.

Conclusions: The ML algorithm showed promise in matching physician adjudication and subtyping stroke cases. Future work is required to refine the methods to automate stroke epidemiology with improved accuracy and granularity.

Abstract TP207: Sex Differences in Cardiovascular Risk Profiles of Patients with Diabetes in the Greater Cincinnati/ Northern Kentucky Stroke Study

Introduction: Diabetes mellitus (DM) carries a greater stroke risk for females than males, possibly because of a difference in cardiovascular risk profiles between females and males with DM. Our aim was to compare the sex-specific risk factor profiles for patients with DM with those without DM among patients with acute ischemic stroke (AIS) in the Greater Cincinnati/ Northern Kentucky Stroke Study (GCNKSS).

Methods: The GCNKSS ascertained cases of AIS in 2005 and 2010 among adult (age ≥20 years) residents of a biracial population of 1.3 million. Past and current stroke risk factors, obtained via chart review, were compared between those with and without DM using chi-square to examine bivariate differences and multiple logistic regression to examine sex-specific profiles. P < 0.05 was considered statistically significant.

Results: There were 3515 patients with incident AIS; 1919 (55%) were female, 697 (20%) were black, and 1146 (33%) had DM. A lower proportion of females with DM were over 65 years old compared with those without DM. The proportion of males >65 with DM was not significantly different from that of males without DM. Among both females and males with DM, significantly more were Black, obese, and had histories of hypertension, high cholesterol, CAD and myocardial infarction compared to those without DM. In sex-specific adjusted analyses, women with DM were significantly less likely to be over 65 and more likely to have CAD than women without DM, whereas age and CAD were not significant factors in differentiating the profiles of men with and without DM.

Conclusions: The result that females had their strokes at a younger age if they had a history of DM, and that no such age difference existed in males, suggests that DM is more severe and has a greater negative impact on females than males. As opposed to males, females with DM were also more likely to have CAD compared to those without DM, consistent with a possible sex difference in the association between DM and vascular disease.

Abstract WP213: Comparison of Clinical and Imaging Characteristic of Cryptogenic Stroke to Known Ischemic Subtypes

Introduction: Cryptogenic stroke is defined as not attributable to an identified source despite standard evaluation. The absence of small vessel or large artery disease in such evaluation suggests that cryptogenic stroke may be largely cardioembolic. We hypothesized that cryptogenic stroke would be similar to cardioembolic stroke in clinical and imaging characteristics.

Methods: The Greater Cincinnati/Northern Kentucky Stroke Study (GCNKSS) is a population-based study that tracks the regional incidence of stroke. A convenient subsample from the 2010 GCNKSS ischemic stroke cohort (N= 368) was selected for detailed neuroimaging analysis. The study physician subtyped cases based on clinical, radiographic and laboratory findings (carotid ultrasound, echocardiography, vascular imaging). Subtypes included cryptogenic, cardioembolic, large-vessel, small-vessel, undetermined, and other. Three radiologists performed imaging analysis including number of acute infarcts, location and white matter hyperintensity (WMH). Infarct volume was segmented using manual tracing.

Results: Of 368 ischemic stroke cases with imaging data, subtypes were 26.4% cryptogenic, 16.3% large vessel, 15.5% small vessel, 24.7% cardioembolic, 5.4% undetermined, and 11.7% other. Compared to cardioembolic, cryptogenic stroke patients were younger, had less hypertension, higher alcohol use, smaller infarct volume and differed in location of stroke. Cryptogenic stroke had more clinical and radiological features in common with large and small-vessel stroke (Table). Undetermined and other had no significant differences to cryptogenic.

Conclusion: Contrary to our hypothesis, cryptogenic stroke was different from cardioembolic stroke and appeared more similar to large vessel stroke in clinical and radiological characteristics. Further testing on a larger sample size to evaluate the impact of cardiac event monitoring on subtype distribution is needed.

Abstract TMP61: Preliminary Results of a Population Based Outcomes Pilot Study: the Greater Cincinnati/Northern Kentucky Stroke Study

Background: We previously followed a cohort of survivors longitudinally with direct interview for outcomes. We then proved that we could obtain similar outcomes by tracking people in a health information exchange followed by first phone call contact at 3 months, thus minimizing contact. This study sought to determine the feasibility of estimating population-based post-stroke outcomes using information available in the electronic medical record (EMR) without any patient contact.

Methods: Our study is a retrospective population-based epidemiology project that ascertains hospitalized strokes via ICD-discharge codes (ICD-9 430-436, ICD-10 I60-I67, G45-G46). Our study region encompasses 5 greater Cincinnati counties; study period 1/1/15-12/31/15. For this pilot outcomes study, we identified all ischemic strokes that presented to a system of 4 hospitals and performed phone calls at 3 and 6 months to determine current place of residence and functional outcomes including the modified Rankin Score (mRS) and the Euroqol (EQ-5D). Simultaneously, our lead Study Coordinator reviewed all available EMR records and used this information to estimate outcome status blinded to phone call results. We compared the “gold-standard” of interview-determined place of residence, mRS and EQ-5D to those estimated from EMR using the either the Kappa statistic or interclass correlation (ICC), as appropriate.

Results: See Table for details. Using standard definitions of Kappa/ICC, estimation of 3- and 6-mo place of residence was “almost perfect” and estimation of mRS grade and EQ-5D was “substantial”. Censoring observations where no EMR information was available did not reduce Kappa/ICC.

Conclusion: This work shows promise in using EMR information to accurately estimate post-stroke outcomes without patient contact, to allow a population-based estimation of outcome. Future work will involve machine-learning to improve our accuracy in outcomes estimation from EMR information.

Abstract 139: Trends in Ischemic Stroke Subtype Over a 17-Year Period

Introduction: Overall US stroke incidence rates have declined. Prior analysis of the Cincinnati region has demonstrated more thorough diagnostic workups coinciding with decreased proportion of cryptogenic and increased proportion of cardioembolic strokes over time in those patients presenting to the ED. We now examine trends in population-based incidence rates of stroke subtypes.

Methods: Within the Greater Cincinnati/Northern Kentucky catchment area of 1.3 million, all strokes were ascertained between July 1993 and June 1994 and in 1999, 2005 and 2010. Incidence rates per 100,000, age-, race- and sex-adjusted to the 2000 US population, and associated 95% confidence intervals were calculated. Changes in stroke-subtype proportions over time were examined using a general linear model.

Results: There were a total of 6859 incident ischemic strokes (1709 in 1993/94, 1778 in 1999, 1681 in 2005, and 1691 in 2010; age ≥20 years), of which 1290 (18.8%) were black and 3846 (56.1%) female. The Table shows subtype-adjusted incident rates by study period. Incidence rates of both small- and large-vessel etiology showed no significant change over time. Incidence rates of both cardioembolic and other known etiology increased significantly over time, whereas incidence rates of unknown subtype decreased significantly.

Conclusions: In our large, biracial population-based cohort, while overall stroke incidence rates have been stable or declining over the last 17 years, trends for individual stroke subtypes have varied. Consistent with our prior analyses, more strokes have been attributed to cardioembolic etiology, whereas strokes attributable to small-vessel and large-vessel etiology have remained stable. The increase in cardioembolic strokes may be due to age and/or prolonged cardiac monitoring. Future analysis of age-adjusted rates for atrial fibrillation over time is warranted.

Ischemic lesions, blood pressure dysregulation, and poor outcomes in intracerebral hemorrhage

OBJECTIVE

To evaluate the associations among diffusion-weighted imaging (DWI) lesions, blood pressure (BP) dysregulation, MRI markers of small vessel disease, and poor outcome in a large, prospective study of primary intracerebral hemorrhage (ICH).

METHODS

The Ethnic/Racial Variations of Intracerebral Hemorrhage (ERICH) study is a multicenter, observational study of ICH among white, black, and Hispanic patients.

RESULTS

Of 600 patients, mean (±SD) age was 60.8 ± 13.6 years, median (interquartile range) ICH volume was 9.1 mL (3.5-20.8), and 79.6% had hypertension. Overall, 26.5% of cases had DWI lesions, and this frequency differed by race/ethnicity (black 33.8%, Hispanic 24.9%, white 20.2%, overall p = 0.006). A logistic regression model of variables associated with DWI lesions included lower age (odds ratio [OR] 0.721, p = 0.002), higher first recorded systolic BP (10-unit OR 1.12, p = 0.002), greater change in mean arterial pressure (MAP) prior to the MRI (10-unit OR 1.10, p = 0.037), microbleeds (OR 1.99, p = 0.008), and higher white matter hyperintensity (WMH) score (1-unit OR 1.16, p = 0.002) after controlling for race/ethnicity, leukocyte count, and acute in-hospital antihypertensive treatment. A second model of variables associated with poor 90-day functional outcome (modified Rankin Scale scores 4-6) included DWI lesion count (OR 1.085, p = 0.034) as well as age, ICH volume, intraventricular hemorrhage, Glasgow Coma Scale score, WMH score, race/ethnicity, acute in-hospital antihypertensive treatment, and ICH location.

CONCLUSIONS

These results support the hypotheses that acute BP dysregulation is associated with the development of DWI lesions in primary ICH and that DWI lesions are, in turn, associated with poor outcomes.

Stable incidence but declining case-fatality rates of subarachnoid hemorrhage in a population

OBJECTIVE

To characterize temporal trends in subarachnoid hemorrhage (SAH) incidence and outcomes over 5 time periods in a large population-based stroke study in the United States.

METHODS

All SAHs among residents of the Greater Cincinnati/Northern Kentucky region at least 20 years of age were identified and verified via study physician review in 5 distinct year-long study periods between 1988 and 2010. We abstracted demographics, care patterns, and outcomes, and we compared incidence and case-fatality rates across the study periods.

RESULTS

The incidence of SAH in the 5 study periods (age-, race-, and sex-adjusted to the 2000 US population) was 8.8 (95% confidence interval 6.8-10.7), 9.2 (7.2-11.2), 10.0 (8.0-12.0), 9.0 (7.1-10.9), and 7.7 (6.0-9.4) per 100,000, respectively; the trend in incidence rates from 1988 to 2010 was not statistically significant (p = 0.22). Advanced neurovascular imaging, endovascular coiling, and neurologic intensive care unit availability increased significantly over time. All-cause 5-day (32%-18%, p = 0.01; for trend), 30-day (46%-25%, p = 0.001), and 90-day (49%-29%, p = 0.001) case-fatality rates declined from 1988 to 2010. When we included only proven or highly likely aneurysmal SAH, the declines in case-fatality were no longer statistically significant.

CONCLUSIONS

Although the incidence of SAH remained stable in this population-based region, 5-day, 30-day, and 90-day case-fatality rates declined significantly. Advances in surgical and medical management, along with systems-based changes such as the emergence of neurocritical care units, are potential explanations for the reduced case-fatality.

Untreated Hypertension: A Powerful Risk Factor for Lobar and Nonlobar Intracerebral Hemorrhage in Whites, Blacks, and Hispanics

BACKGROUND

Hypertension is a significant risk factor for intracerebral hemorrhage (ICH). Although ethnic/racial disparities related to hypertension and ICH have been reported, these previous studies were limited by a lack of Hispanics and inadequate power to analyze by ICH location. In the current study, while overcoming these prior limitations, we investigated whether there was variation by ethnicity/race of treated and untreated hypertension as risk factors for ICH.

METHODS

The ERICH study (Ethnic/Racial Variations of Intracerebral Hemorrhage) is a prospective, multicenter, case-control study of ICH among whites, blacks, and Hispanics. Cases were enrolled from 42 recruitment sites. Controls matched to cases 1:1 by age (±5 years), sex, ethnicity/race, and metropolitan area were identified by random-digit dialing. Subjects were interviewed to determine history of hypertension and use of antihypertensive medications. Cases and controls within ethnic groups were compared by using conditional logistic regression. Multivariable conditional logistic regression models were computed for ICH as an overall group and separately for the location subcategories deep, lobar, and infratentorial (brainstem/cerebellar).

RESULTS

Nine hundred fifty-eight white, 880 black, and 766 Hispanic ICH patients were enrolled. For ICH cases, untreated hypertension was higher in blacks (43.6%, P<0.0001) and Hispanics (46.9%, P<0.0001) versus whites (32.7%). In multivariable analyses adjusted for alcohol use, anticoagulation, hypercholesterolemia, education, and medical insurance status, treated hypertension was a significant risk factor across all locations of ICH in whites (odds ratio [OR], 1.57; 95% confidence interval [CI], 1.24-1.98; P<0.0001), blacks (OR, 3.02; 95% CI, 2.16-4.22; P<0.0001), and Hispanics (OR, 2.50; 95% CI, 1.73-3.62; P<0.0001). Untreated hypertension was a substantially greater risk factor for all 3 racial/ethnic groups across all locations of ICH: whites (OR, 8.79; 95% CI, 5.66-13.66; P<0.0001), blacks (OR, 12.46; 95% CI, 8.08-19.20; P<0.0001), and Hispanics (OR, 10.95; 95% CI, 6.58-18.23; P<0.0001). There was an interaction between race/ethnicity and ICH risk (P<0.0001).

CONCLUSIONS

Untreated hypertension confers a greater ICH risk in blacks and Hispanics relative to whites across all anatomic locations of ICH. Accelerated research efforts are needed to improve overall hypertension treatment rates and to monitor the impact of such efforts on racial/ethnic disparities in stroke.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01202864.