Association of Apolipoprotein E With Intracerebral Hemorrhage Risk by Race/Ethnicity: A Meta-analysis

Importance

Genetic studies of intracerebral hemorrhage (ICH) have focused mainly on white participants, but genetic risk may vary or could be concealed by differing nongenetic coexposures in nonwhite populations. Transethnic analysis of risk may clarify the role of genetics in ICH risk across populations.

Objective

To evaluate associations between established differences in ICH risk by race/ethnicity and the variability in the risks of apolipoprotein E (APOE) ε4 alleles, the most potent genetic risk factor for ICH.

Design, Setting, and Participants

This case-control study of primary ICH meta-analyzed the association of APOE allele status on ICH risk, applying a 2-stage clustering approach based on race/ethnicity and stratified by a contributing study. A propensity score analysis was used to model the association of APOE with the burden of hypertension across race/ethnic groups. Primary ICH cases and controls were collected from 3 hospital- and population-based studies in the United States and 8 in European sites in the International Stroke Genetic Consortium. Participants were enrolled from January 1, 1999, to December 31, 2017. Participants with secondary causes of ICH were excluded from enrollment. Controls were regionally matched within each participating study.

Main Outcomes and Measures

Clinical variables were systematically obtained from structured interviews within each site. APOE genotype was centrally determined for all studies.

Results

In total, 13 124 participants (7153 [54.5%] male with a median [interquartile range] age of 66 [56-76] years) were included. In white participants, APOE ε2 (odds ratio [OR], 1.49; 95% CI, 1.24-1.80; P < .001) and APOE ε4 (OR, 1.51; 95% CI, 1.23-1.85; P < .001) were associated with lobar ICH risk; however, within self-identified Hispanic and black participants, no associations were found. After propensity score matching for hypertension burden, APOE ε4 was associated with lobar ICH risk among Hispanic (OR, 1.14; 95% CI, 1.03-1.28; P = .01) but not in black (OR, 1.02; 95% CI, 0.98-1.07; P = .25) participants. APOE ε2 and ε4 did not show an association with nonlobar ICH risk in any race/ethnicity.

Conclusions and Relevance

APOE ε4 and ε2 alleles appear to affect lobar ICH risk variably by race/ethnicity, associations that are confirmed in white individuals but can be shown in Hispanic individuals only when the excess burden of hypertension is propensity score-matched; further studies are needed to explore the interactions between APOE alleles and environmental exposures that vary by race/ethnicity in representative populations at risk for ICH.

Sleep-Disordered Breathing Is Associated With Recurrent Ischemic Stroke

Background and Purpose- Limited data are available about the relationship between sleep-disordered breathing (SDB) and recurrent stroke and mortality, especially from population-based studies, large samples, or ethnically diverse populations. Methods- In the BASIC project (Brain Attack Surveillance in Corpus Christ), we identified patients with ischemic stroke (2010-2015). Subjects were offered screening for SDB with the ApneaLink Plus device, from which a respiratory event index (REI) score ≥10 defined SDB. Demographics and baseline characteristics were determined from chart review and interview. Recurrent ischemic stroke was identified through active and passive surveillance. Cause-specific proportional hazards models were used to assess the association between REI (modeled linearly) and ischemic stroke recurrence (as the event of interest), and all-cause poststroke mortality, adjusted for multiple potential confounders. Results- Among 842 subjects, the median age was 65 (interquartile range, 57-76), 47% were female, and 58% were Mexican American. The median REI score was 14 (interquartile range, 6-26); 63% had SDB. SDB was associated with male sex, Mexican American ethnicity, being insured, nonsmoking status, diabetes mellitus, hypertension, lower educational attainment, and higher body mass index. Among Mexican American and non-Hispanic whites, 85 (11%) ischemic recurrent strokes and 104 (13%) deaths occurred, with a median follow-up time of 591 days. In fully adjusted models, REI was associated with recurrent ischemic stroke (hazard ratio, 1.02 [hazard ratio for one-unit higher REI score, 95% CI, 1.01-1.03]), but not with mortality alone (hazard ratio, 1.00 [95% CI, 0.99-1.02]). Conclusions- Results from this large population-based study show that SDB is associated with recurrent ischemic stroke, but not mortality. SDB may therefore represent an important modifiable risk factor for poor stroke outcomes.

Abstract 17: Apolipoprotein E and Intracerebral Hemorrhage: A Trans-Ethnic Meta-Analysis

Introduction: Risk of lobar and non-lobar intracerebral hemorrhage (ICH) varies among blacks, whites and Hispanics. We sought to determine whether these differences could be due to variability in the effects of Apolipoprotein E (APOE) epsilon (ε) alleles, the most potent genetic risk factor for ICH.

Methods: Primary ICH cases and controls were collected from US and European sites contributing to the International Stroke Genetic Consortium (ISGC). We meta-analyzed the effects of APOE allele status on ICH risk applying a two-stage clustering approach based on race/ethnicity and the contributing study. Models were adjusted for age, sex, history of hypertension, hypercholesterolemia, warfarin, statin and antiplatelet use, smoking and alcohol use. A propensity score analysis was used to model the influence of APOE against the burden of hypertension across races/ethnicities.

Results: 13,124 subjects (54.5% male, median age 66 years) were included. In whites, APOE ε2 (odds ratio (OR)=1.85, 95% confidence interval (CI)=1.27-2.69, p<0.001) and APOE ε4 (OR=1.94, 95% CI=1.58-2.38, p<0.001) were independently associated with lobar ICH risk, however within self-identified Hispanics and blacks, no associations were found (Figure). After propensity score-matching for hypertension burden, APOE ε4 was associated with lobar ICH risk among whites (OR=1.12, 95% CI=1.08-1.17) and Hispanics (OR=1.07, 95% CI=1.01-1.15, p=0.01), but not blacks (OR=1.02 95% CI=0.98-1.07, p=0.251). APOE ε2 and ε4 did not show an effect on non-lobar ICH risk in any race/ethnicity.

Conclusion: APOE ε4 and ε2 alleles affect lobar ICH risk variably by race and ethnicity. Associations are confirmed in whites but can be shown in Hispanics only when the excess burden of hypertension is propensity score-matched. Further studies are needed to explore interactions between APOE alleles and environmental exposures that vary by race and ethnicity in representative populations at risk for ICH.

Abstract TP179: Selecting an Outcome for Sleep Apnea Treatment Trials in Stroke: A Comparative Analysis

Introduction: Post-stroke sleep apnea (SA) affects the majority of stroke patients and is associated with poorer stroke outcomes. To select appropriate endpoints for a future SA treatment trial in stroke patients, we assessed the predictive ability between a variety of important outcome measures and SA severity, as measured by the apnea-hypopnea index (AHI), within a population-based stroke study.

Methods: Ischemic stroke patients enrolled in the Brain Attack Surveillance in Corpus Christi (BASIC) project were offered SA screening shortly after stroke with a portable sleep apnea test (ApneaLink Plus). Apnea-hypopnea index (AHI) was calculated as the sum of apneas and hypopneas during the nocturnal recording. Subjects had baseline information collected from chart abstraction and interview, and had 3-month outcomes assessed in-person including an activities of daily living (ADL)/instrumental ADL(IADL) scale, NIHSS, Modified Mini-Mental State exam (3MS), and 12-item Stroke-specific Quality of Life scale (SSQOL). Predictive R 2 (a measure of how well models predict responses for new observations) from linear regression models was used to compare predictive ability of models with and without AHI, adjusted for significant predictors of outcome.

Results: Within 455 subjects, the predictive R 2 was 31.7% for ADL/IADL, 23.2% for SSQOL, 25.0% for the 3MS, and 11.7% for NIHSS in the model without AHI. When AHI was included in the models, the predictive R 2 increased to 32.8% for ADL/IADL and increased to 11.9% for NIHSS; however, the predictive R 2 decreased by 0.1% for SSQOL and decreased by 0.2% for 3MS.

Conclusions: In future trials that test SA treatment’s effect on stroke outcomes at 3 months, improvement is most likely to be observed from a functional outcome, such as that measured by the ADL/IADL scale.

Abstract TP215: Clinical Phenotypes of Obstructive Sleep Apnea in Stroke Patients: A Cluster Analysis

Introduction: Obstructive sleep apnea (OSA) is highly prevalent in stroke survivors. Untreated OSA is associated with an increased risk of adverse cardiovascular outcomes and OSA treatment may improve neurological recovery in stroke survivors, yet OSA in stroke patients remains poorly characterized. To our knowledge, this is the first study aiming to identify OSA phenotypes in stroke survivors.

Methods: Patients (n=451) with ischemic strokes and OSA (apnea-hypopnea index (AHI) ≥ 10 using a cardiopulmonary screening device (ApneaLink Plus)) were identified from the Brain Attack Surveillance in Corpus Christi (BASIC) project. Latent class analysis was performed based on the following variables: age, sex, race/ethnicity, AHI, pre-stroke snoring, pre-stroke tiredness/fatigue, pre-stroke sleep duration, prior stroke history, initial NIHSS, BMI, hypertension, diabetes, atrial fibrillation, coronary artery disease, and congestive heart failure.

Results: A model with 3 phenotype clusters provided the best fit. Cluster 1 (n=55, 12%) was defined by higher NIHSS scores and high prevalence of snoring. Patients in cluster 2 (n=253, 56%) were younger and had relatively low NIHSS scores. Cluster 3 (n=143, 32%) included patients with severe OSA and higher prevalence of medical comorbidities.

Conclusion: Ischemic stroke survivors with OSA can be categorized into three clinical phenotype clusters characterized by differences in stroke severity, OSA severity, patient age and medical comorbidities. This highlights the heterogeneity of post-stroke OSA. Awareness of the different faces of OSA in patients with ischemic stroke may help clinicians identify OSA in their patients, and informs research concerning the pathophysiology and prognostication of post-stroke OSA.

Recurrent stroke in midlife is associated with not having a primary care physician

OBJECTIVE

To determine using a population-based study whether midlife stroke patients having a primary care physician (PCP) at the time of first stroke have a lower risk of stroke recurrence and mortality than those who do not have a PCP.

METHODS

First-ever ischemic stroke patients 45 to 64 years of age at stroke onset were ascertained through the Brain Attack Surveillance in Corpus Christi (BASIC) project from 2000 to 2013 in Texas. Cox proportional hazards models were used to examine the association between not having a PCP and stroke recurrence or all-cause mortality in separate models. Cases were followed up for up to 5 years or until December 31, 2013, whichever came first. Cases were censored for recurrence if they died before experiencing a recurrent event. We adjusted for clinical risk factors that could be associated with having a PCP and recurrence or mortality.

RESULTS

There were 663 first-occurrence ischemic stroke cases. Of these, 77% had a PCP, 43% were female, and average age was 55.6 years. Five-year recurrence risk was 14.6%, and mortality risk was 19.2%. Not having a PCP was associated with higher recurrence risk (adjusted hazard ratio 1.75, 95% confidence interval 1.02-3.02). Having a PCP was not associated with mortality. Sensitivity analyses showed that results were robust to different ways to adjust for chronic conditions.

CONCLUSION

This study found lower rates of stroke recurrence among those with a PCP at the time of first stroke. Future studies could determine the value of establishing a PCP before stroke hospital discharge for secondary stroke prevention.

Effectiveness of a short video-based educational intervention on factors related to clinical trial participation in adolescents and young adults: a pre-test/post-test design

BACKGROUND

Poor clinical trial enrollment continues to be pervasive and is especially problematic among young adults and youth, and among minorities. Efforts to address barriers to enrollment have been predominantly focused on adult diseased populations. Because older adults may already have established attitudes, it is imperative to identify strategies that target adolescents and young adults. The purpose of this study was to test the effectiveness of an educational video on factors related to clinical trial participation among a healthy adolescent and young adult population.

METHODS

Participants completed a 49-item pre-test, viewed a 10-min video, and completed a 45-item post-test to assess changes in attitudes, knowledge, self-efficacy, receptivity to, and intention to participate (primary outcome) in clinical trials. Descriptive statistics, paired samples t-tests, and Wilcoxon signed-rank tests were conducted.

RESULTS

The final analyses included 935 participants. The mean age was 20.7 years, with almost 70% aged 18 to 20 years. The majority were female (73%), non-Hispanic (92.2%), white (70%), or African American (20%). Participants indicated a higher intention to participate in a clinical trial (p < 0.0001) and receptivity to hearing more about a clinical trial (p < 0.0001) after seeing the video. Intention to participate (definitely yes and probably yes) increased by an absolute 18% (95% confidence interval 15-22%). There were significant improvements in attitudes, knowledge, and self-efficacy scores for all participants (p < 0.0001).

CONCLUSIONS

The results of this study showed strong evidence for the effectiveness of a brief intervention on factors related to participation in clinical trials. This supports the use of a brief intervention, in a traditional educational setting, to impact the immediate attitudes, knowledge, self-efficacy, and intention to participate in clinical trial research among diverse, healthy adolescents and young adults.

Sleep apnea screening is uncommon after stroke

OBJECTIVE/BACKGROUND

To assess (1) pre and post-stroke screening for sleep apnea (SA) within a population-based study without an academic medical center, and (2) ethnic differences in post-stroke sleep apnea screening among Mexican Americans (MAs) and non-Hispanic whites (NHWs).

PATIENTS/METHODS

MAs and NHWs with stroke in the Brain Attack Surveillance in Corpus Christi project (2011-2015) were interviewed shortly after stroke about the pre-stroke period, and again at approximately 90 days after stroke in reference to the post-stroke period. Questions included whether any clinical provider directly asked about snoring or daytime sleepiness or had offered polysomnography. Logistic regression tested the association between these outcomes and ethnicity both unadjusted and adjusted for potential confounders.

RESULTS

Among 981 participants, 63% were MA. MAs in comparison to NHWs were younger, had a higher prevalence of hypertension, diabetes, and never smoking, a higher body mass index, and a lower prevalence of atrial fibrillation. Only 17% reported having been offered SA diagnostic testing pre-stroke, without a difference by ethnicity. In the post-stroke period, only 50 (5%) participants reported being directly queried about snoring; 86 (9%) reported being directly queried about sleepiness; and 55 (6%) reported having been offered polysomnography. No ethnic differences were found for these three outcomes, in unadjusted or adjusted analyses.

CONCLUSIONS

Screening for classic symptoms of SA, and formal testing for SA, are rare within the first 90 days after stroke, for both MAs and NHWs. Provider education is needed to raise awareness that SA affects most patients after stroke and is associated with poor outcomes.

17p12 Influences Hematoma Volume and Outcome in Spontaneous Intracerebral Hemorrhage

BACKGROUND AND PURPOSE

Hematoma volume is an important determinant of clinical outcome in spontaneous intracerebral hemorrhage (ICH). We performed a genome-wide association study (GWAS) of hematoma volume with the aim of identifying novel biological pathways involved in the pathophysiology of primary brain injury in ICH.

METHODS

We conducted a 2-stage (discovery and replication) case-only genome-wide association study in patients with ICH of European ancestry. We utilized the admission head computed tomography to calculate hematoma volume via semiautomated computer-assisted technique. After quality control and imputation, 7 million genetic variants were available for association testing with ICH volume, which was performed separately in lobar and nonlobar ICH cases using linear regression. Signals with P<5×10-8 were pursued in replication and tested for association with admission Glasgow coma scale and 3-month post-ICH dichotomized (0-2 versus 3-6) modified Rankin Scale using ordinal and logistic regression, respectively.

RESULTS

The discovery phase included 394 ICH cases (228 lobar and 166 nonlobar) and identified 2 susceptibility loci: a genomic region on 22q13 encompassing PARVB (top single-nucleotide polymorphism rs9614326: β, 1.84; SE, 0.32; P=4.4×10-8) for lobar ICH volume and an intergenic region overlying numerous copy number variants on 17p12 (top single-nucleotide polymorphism rs11655160: β, 0.95; SE, 0.17; P=4.3×10-8) for nonlobar ICH volume. The replication included 240 ICH cases (71 lobar and 169 nonlobar) and corroborated the association for 17p12 (P=0.04; meta-analysis P=2.5×10-9; heterogeneity, P=0.16) but not for 22q13 (P=0.49). In multivariable analysis, rs11655160 was also associated with lower admission Glasgow coma scale (odds ratio, 0.17; P=0.004) and increased risk of poor 3-month modified Rankin Scale (odds ratio, 1.94; P=0.045).

CONCLUSIONS

We identified 17p12 as a novel susceptibility risk locus for hematoma volume, clinical severity, and functional outcome in nonlobar ICH. Replication in other ethnicities and follow-up translational studies are needed to elucidate the mechanism mediating the observed association.

Sleep disorders and the risk of stroke

INTRODUCTION

Stroke is a major cause of disability and death in the United States and across the world, and the incidence and prevalence of stroke are expected to rise significantly due to an aging population. Obstructive sleep apnea, an established independent risk factor for stroke, is a highly prevalent disease that is estimated to double the risk of stroke. It remains uncertain whether non-apnea sleep disorders increase the risk of stroke. Areas covered: This paper reviews the literature describing the association between incident stroke and sleep apnea, rapid eye movement sleep behavior disorder, restless legs syndrome, periodic limb movements of sleep, insomnia, and shift work. Expert commentary: Trials of continuous positive airway pressure for stroke prevention in sleep apnea patients have been largely disappointing, but additional trials that target populations not yet optimally studied are needed. Self-reported short and long sleep duration may be associated with incident stroke. However, abnormal sleep duration may be a marker of chronic disease, which may itself be associated with incident stroke. The relationship between non-apnea sleep disorders and incident stroke deserves further attention. Identification of specific non-apnea sleep disorders or sleep problems that convey an increased risk for stroke may provide novel targets for stroke prevention.

Lack of Worsening of Sleep-Disordered Breathing After Recurrent Stroke in the BASIC Project

STUDY OBJECTIVES

To investigate the difference in sleep-disordered breathing (SDB) prevalence and severity after an index and recurrent stroke.

METHODS

In a sample of 40 subjects, home sleep apnea tests were performed a median of 10 days after an index ischemic stroke and 14 days after a recurrent ischemic stroke. A respiratory event index (REI) of ≥ 10 events/h (apneas plus hypopneas per hour of recording) was used to define clinically significant SDB. The relative difference in REI or relative SDB prevalence was used to compare the post-recurrent stroke measurement with that made after the index stroke, and was expressed as a rate ratio (RR) or prevalence ratio (PR). Adjusted regression models (negative binomial for REI and log binomial for SDB) included change in body mass index and time between the events.

RESULTS

The median time from index to recurrent stroke was 330.5 days (interquartile range [IQR]: 103.5, 766.5). The median REI was 17.5 (IQR: 9.0, 32.0) after the index stroke and 18.0 (IQR: 11.0, 25.5) after the recurrent stroke. The within-subject median difference was zero (IQR: -9, 7.5). The relative difference in REI was not significant in unadjusted or adjusted (RR: 0.97 [95% confidence interval: 0.76, 1.24]) models. The prevalence of SDB was not different after the recurrent stroke compared with the index stroke, in unadjusted or adjusted (PR: 1.10 [95% confidence interval: 0.91, 1.32]) models.

CONCLUSIONS

In this within-subject, longitudinal study, neither severity nor prevalence of SDB worsened after recurrent stroke.

Intracerebral hemorrhage and sleep-disordered breathing

OBJECTIVE/BACKGROUND

Limited data are available on sleep-disordered breathing (SDB) following intracerebral hemorrhage (ICH). Our aim was to characterize the objective measures of post-ICH SDB and questionnaire-reported pre-ICH sleep characteristics, overall and by ethnicity.

PATIENTS/METHODS

Participants with ICH who were enrolled in the population-based Brain Attack Surveillance in Corpus Christi project (2010-2016) reported their pre-ICH sleep duration and completed the Berlin Questionnaire to characterize pre-ICH risk of SDB. A subsample was screened for SDB (respiratory event index ≥10) using ApneaLink Plus portable monitoring. Ethnic differences in post-ICH SDB or questionnaire-reported pre-ICH sleep characteristics were assessed using a log binomial model or a linear regression model or a Fisher's exact test.

RESULTS

ICH cases (n = 298) were enrolled (median age = 68 years, 67% Mexican American). Among 62 cases with complete ApneaLink data, median time to post-ICH SDB screening was 11 days (IQR: 6, 19). Post-ICH SDB prevalence was 46.8% (95% CI: 34.4-59.2), and this rate did not differ by ethnicity (p = 1.0). Berlin Questionnaires for 109 of the 298 ICH cases (36.6% (95% CI: 31.1-42.0)) suggested a high risk for pre-ICH SDB, and the median pre-ICH sleep duration was eight hours (IQR: 6, 8). After adjusting for confounders, there was no difference in ethnicity in high risk for pre-ICH SDB or pre-ICH sleep duration.

CONCLUSIONS

Nearly half of the patients had objective confirmation of SDB after ICH, and more than one-third had questionnaire evidence of high risk for pre-ICH SDB. Opportunities to address SDB may be common both before and after ICH.

Abstract WP280: Sleep Apnea Screening is Uncommon After Stroke

Introduction: Sleep apnea (SA) predicts poor functional outcome and mortality after stroke. Minority populations, including Mexican Americans (MAs), have worse outcomes after stroke than non-Hispanic whites (NHWs) and tend to have poorer access to care. We therefore sought to (1) assess access to SA-related care among post-stroke patients within a population-based study without an academic medical center, and (2) to compare ethnic differences in access to SA-related care in the post-stroke period in MAs and NHWs.

Methods: MA and NHWs with ischemic stroke or intracerebral hemorrhage in the Brain Attack Surveillance in Corpus Christi project between 2011-2015 were interviewed at approximately 90 days after stroke in reference to the post-stroke period. Questions included whether their clinical provider directly asked about (1) snoring or (2) daytime sleepiness, or (3) had offered polysomnography. Logistic regression was used to test the association between ethnicity and the three outcomes unadjusted and adjusted for potential confounders: age, sex, insurance status, primary care provider status (PCP), BMI, stroke type, NIHSS at stroke presentation, hypertension, diabetes, atrial fibrillation, hyperlipidemia, and current smoking.

Results: Of the almost 1,000 respondents, 49% were male, 63% MA, 81% had hypertension, 48% had diabetes, and 10% did not have a PCP. Mean age was 69 (SD=12) and mean BMI was 30 (SD=6.8). MAs were younger, had a higher BMI, greater prevalence of hypertension, diabetes, never smoking, and lower prevalence of atrial fibrillation than NHWs. Of the 985 respondents to the symptom questions, 50 (5%) reported being directly queried about snoring and 86 (9%) reported being directly queried about sleepiness. Fifty-five of 981 (6%) reported having been offered polysomnography by their providers. No ethnic differences were found among the three outcomes in unadjusted or adjusted analyses.

Conclusion: Screening for classic symptoms of SA and offers for formal testing of SA by clinical providers are rare by 90 days post-stroke, without ethnic differences. Provider education is needed to raise awareness about the very high prevalence of SA among stroke patients and its association with poor outcomes after stroke.

Abstract WMP59: Sleep Apnea is Associated with the Combined Endpoint of Recurrent Stroke and Post-Stroke Mortality

Introduction: No data are available about the relationship between sleep apnea (SA) and recurrent stroke and mortality from population-based studies, large samples, or ethnically diverse populations.

Methods: In the Brain Attack Surveillance in Corpus Christi (BASIC) project, we identified patients with ischemic stroke between 2010-2015. Subjects who enrolled were offered screening for SA with the ApneaLink Plus device from which an apnea-hypopnea index (AHI) was derived (≥10 defined SA). Demographics and baseline characteristics were determined from chart review and interview. Recurrent ischemic stroke was identified through active and passive surveillance and confirmed by study neurologists. All-cause mortality was identified through Texas Department of State Health Services records. Cox proportional-hazards models were used to assess the association between AHI (modeled linearly) and combined ischemic stroke recurrence and mortality unadjusted and adjusted for multiple potential confounders.

Results: Of the 842 subjects, the median age was 65 (IQR: 57, 76), 47% were female, 58% were Mexican American, and 34% were non-Hispanic white. The median AHI was 14 (IQR: 6, 26); 63% had SA. SA was associated with male sex, Mexican American ethnicity, being insured, nonsmoking status, diabetes, hypertension, lower educational attainment, and higher BMI. In the time period (median time to event 584 days), 90 (10.7%) recurrent strokes and 125 (14.8%) deaths occurred with a cumulative incidence of recurrence or death of 202 (24%). AHI was associated with the combined endpoint in unadjusted (HR=1.09 per one unit increase in AHI (95%CI: 1.08, 1.10)) and fully adjusted models (HR=1.09 (95%CI: 1.08, 1.10)). Mexican American ethnicity was associated with the endpoint (HR=1.71 (95%CI: 1.16, 2.54) in the fully adjusted model.

Conclusion: SA is associated with the combined endpoint of recurrent ischemic stroke and mortality in this population-based study. Mexican Americans are also at higher risk of recurrent stroke and death following ischemic stroke than non-Hispanic whites. SA may therefore represent an important modifiable risk factor for poor stroke outcomes and a target to reduce ethnic stroke disparities.

Wake-up stroke is not associated with sleep-disordered breathing in women

Background

We sought to investigate the frequency of wake-up stroke (WUS) and its association with sleep-disordered breathing (SDB) in women.

Methods

Within a population-based study, women with acute ischemic stroke were asked about their stroke symptom onset time. SDB screening was performed with the well-validated ApneaLink Plus device; SDB was defined by a respiratory event index ≥10. Logistic regression was used to test the association between SDB presence and severity and WUS unadjusted and adjusted for potential confounders including prestroke depression and sleep duration.

Results

Among 466 participants, the median age was 67.0 years (interquartile range [IQR] 58.0, 77.0), 55% were Mexican American, and the median initial NIH Stroke Scale score was 3.0 (IQR 1.0, 6.0). Stroke symptom onset occurred during nocturnal sleep (25.3%), during a nap (3.9%), during wakefulness (65.9%), or unknown (4.9%). In those with SDB screening performed (n = 259), a median of 11 days (IQR 5, 17) poststroke, WUS was not associated with the presence or severity (respiratory event index) of SDB in unadjusted or adjusted analysis.

Conclusions

In this population-based study, WUS represented about 30% of all generally mild severity ischemic strokes in women and was not associated with SDB.

A Randomized Trial of Central Venous Catheter Type and Thrombosis in Critically Ill Neurologic Patients

BACKGROUND

Observational studies suggest peripherally inserted central venous catheters (PICCs) are associated with a high risk of catheter-related large vein thrombosis (CRLVT) in critically ill neurologic patients. We evaluated the difference in thrombosis risk between PICCs and centrally inserted central venous catheters (CICVCs).

METHODS

We conducted a pragmatic, randomized controlled trial of critically ill adult neurologic patients admitted to neurological and trauma critical care units at two level I trauma centers. Patients were randomized to receive either a PICC or CICVC and undergo active surveillance for CRLVT or death within 15 days of catheter placement.

RESULTS

In total, 39 subjects received a PICC and 41 received a CICVC between February 2012 and July 2015. The trial was stopped after enrollment of 80 subjects due to feasibility affected by slow enrollment and funding. In the primary intention-to-treat analysis, 17 (43.6 %) subjects that received a PICC compared to 9 (22.0 %) that received a CICVC experienced the composite of CRLVT or death, with a risk difference of 21.6 % (95 % CI 1.57-41.71 %). Adjusted common odds ratio of CRLVT/death was significantly higher among subjects randomized to receive a PICC (adjusted OR 3.08; 95 % CI 1.1-8.65). The higher adjusted odds ratio was driven by risk of CRLVT, which was higher in those randomized to PICC compared to CICVC (adjusted OR 4.66; 95 % CI 1.3-16.76) due to increased large vein thrombosis without a reduction in proximal deep venous thrombosis.

CONCLUSIONS

Our trial demonstrates that critically ill neurologic patients who require a central venous catheter have significantly lower odds of ultrasound-diagnosed CRLVT with placement of a CICVC as compared to a PICC.

Sex differences in the impact of acute stroke treatment in a population-based study: a sex-specific propensity score approach

PURPOSE

We investigated whether sex modifies the association of acute stroke treatment on functional outcome using propensity score (PS) methods to minimize confounding and to explore the differential effects of confounders by sex.

METHODS

We included tissue plasminogen activator (tPA) treated (n = 84) and nontreated ischemic stroke cases (n = 143) from a population-based stroke study (2008-2013). The PS model that estimated the probability of receiving tPA included interactions between sex and treatment predictors. The outcome model included sex, tPA, and their interaction. In addition, sex-specific PS values were included as a continuous covariate and modeled using splines. We compared the results with conventional methods of statistical adjustment.

RESULTS

Conventional methods of adjustment suggested that women receive greater benefit from tPA than men. After taking into consideration that the influence of confounders, specifically age and stroke severity, differed by sex, we found no sex difference in the tPA-functional outcome association (P = .94).

CONCLUSIONS

Using PS methods that considered confounding of the sex × treatment interaction, we did not find that the association of tPA with functional outcome differed for women and men. Our findings may have implications for the methodologic approaches used to address confounding in studies that seek to compare stroke treatment effects by sex.

Reach Out Churches: A Community-Based Participatory Research Pilot Trial to Assess the Feasibility of a Mobile Health Technology Intervention to Reduce Blood Pressure Among African Americans

Innovative strategies are needed to reduce the hypertension epidemic among African Americans. Reach Out was a faith-collaborative, mobile health, randomized, pilot intervention trial of four mobile health components to reduce high blood pressure (BP) compared to usual care. It was designed and tested within a community-based participatory research framework among African Americans recruited and randomized from churches in Flint, Michigan. The purpose of this pilot study was to assess the feasibility of the Reach Out processes. Feasibility was assessed by willingness to consent (acceptance of randomization), proportion of weeks participants texted their BP readings (intervention use), number lost to follow-up (retention), and responses to postintervention surveys and focus groups (acceptance of intervention). Of the 425 church members who underwent BP screening, 94 enrolled in the study and 73 (78%) completed the 6-month outcome assessment. Median age was 58 years, and 79% were women. Participants responded with their BPs on an average of 13.7 (SD = 10.7) weeks out of 26 weeks that the BP prompts were sent. All participants reported satisfaction with the intervention. Reach Out, a faith-collaborative, mobile health intervention was feasible. Further study of the efficacy of the intervention and additional mobile health strategies should be considered.

Barriers and facilitators to ED physician use of the test and treatment for BPPV

BACKGROUND

The test and treatment for benign paroxysmal positional vertigo (BPPV) are evidence-based practices supported by clinical guideline statements. Yet these practices are underutilized in the emergency department (ED) and interventions to promote their use are needed. To inform the development of an intervention, we interviewed ED physicians to explore barriers and facilitators to the current use of the Dix-Hallpike test (DHT) and the canalith repositioning maneuver (CRM).

METHODS

We conducted semi-structured in-person interviews with ED physicians who were recruited at annual ED society meetings in the United States. We analyzed data thematically using qualitative content analysis methods.

RESULTS

Based on 50 interviews with ED physicians, barriers that contributed to infrequent use of DHT/CRM that emerged were (1) prior negative experiences or forgetting how to perform them and (2) reliance on the history of present illness to identify BPPV, or using the DHT but misattributing patterns of nystagmus. Based on participants' responses, the principal facilitator of DHT/CRM use was prior positive experiences using these, even if infrequent. When asked which clinical supports would facilitate more frequent use of DHT/CRM, participants agreed supports needed to be brief, readily accessible, and easy to use, and to include well-annotated video examples.

CONCLUSIONS

Interventions to promote the use of the DHT/CRM in the ED need to overcome prior negative experiences with the DHT/CRM, overreliance on the history of present illness, and the underuse and misattribution of patterns of nystagmus. Future resources need to be sensitive to provider preferences for succinct information and video examples.

Effective equations governing an active poroelastic medium

In this work, we consider the spatial homogenization of a coupled transport and fluid–structure interaction model, to the end of deriving a system of effective equations describing the flow, elastic deformation and transport in an active poroelastic medium. The ‘active’ nature of the material results from a morphoelastic response to a chemical stimulant, in which the growth time scale is strongly separated from other elastic time scales. The resulting effective model is broadly relevant to the study of biological tissue growth, geophysical flows (e.g. swelling in coals and clays) and a wide range of industrial applications (e.g. absorbant hygiene products). The key contribution of this work is the derivation of a system of homogenized partial differential equations describing macroscale growth, coupled to transport of solute, that explicitly incorporates details of the structure and dynamics of the microscopic system, and, moreover, admits finite growth and deformation at the pore scale. The resulting macroscale model comprises a Biot-type system, augmented with additional terms pertaining to growth, coupled to an advection–reaction–diffusion equation. The resultant system of effective equations is then compared with other recent models under a selection of appropriate simplifying asymptotic limits.

Abstract WP308: Impact of Ethnicity on Access to Sleep Apnea Screening and Testing In Stroke Survivors

Introduction: Sleep apnea (SA) following stroke is present in approximately 72% of patients. SA leads to increased stroke risk and is associated with poorer prognosis. Aggressive risk factor modification after stroke is widely accepted, yet evaluation for SA is not routine practice. We hypothesized that fewer Mexican-Americans (MA) are screened for and offered SA testing following stroke than non-Hispanic whites (NHW).

Methods: Between July 2011 and May 2016, MAs and NHWs with ischemic stroke or intracerebral hemorrhage in the Brain Attack Surveillance in Corpus Christi (BASIC) project were asked during a baseline interview (a median 8 days (interquartile range=16) after presentation), if they had reported symptoms of SA to their doctor, had been asked by their doctor about SA symptoms, and if their doctor had offered formal SA testing. Logistic regression was used to test the association between ethnicity and these three outcomes unadjusted and adjusted for potential confounders such as sex, age, insurance status, and BMI.

Results: Of the 1,086 MA and 621 NHW participants, median age was 68 and 49% were women. Two hundred nineteen (20.2%) MAs self-reported symptoms of SA compared with 114 (18.4%) NHW (p=0.36). One hundred forty-seven (13.5%) MAs were asked about symptoms of SA by their doctors compared with 76 (12.2%) NHWs (p=0.44). One hundred ninety-two (17.7%) MAs were offered a SA test compared with 112 (18.0%) NHWs (p=0.86). MA ethnicity was associated with a lower odds of reporting being offered SA testing in the fully adjusted model (odds ratio 0.751 (95% CI: 0.567, 0.995)), but was not associated with the other two outcomes.

Conclusions: Screening for SA in post-stroke patients is poor overall, and worse for MAs. Given the important relationship between SA and stroke, educational interventions are needed to improve provider awareness surrounding SA screening in stroke survivors.

Abstract 154: Genetic Variants in CETP That Increase HDL Levels also Increase Risk of Intracerebral Hemorrhage

Introduction: In observational studies, higher plasma high-density lipoprotein cholesterol (HDL-C) has been associated with increased risk of spontaneous intracerebral hemorrhage (ICH). Common DNA sequence variants within the cholesteryl ester transfer protein ( CETP ) gene decrease CETP protein activity and increase plasma HDL-C; as such, medicines that inhibit CETP and raise HDL-C are in clinical development to combat coronary artery disease.

Hypothesis: Common CETP DNA sequence variants associated with higher HDL-C also increase risk for ICH.

Methods: We performed a two-stage case-control genetic association study in Caucasians. The discovery phase utilized data on 12 independent loci within CETP (+/- 50 kilobases) from 3 genome-wide association studies of ICH. Replication involved direct genotyping in 5 additional studies. We also constructed a genetic risk score with 7 independent CETP variants and tested it for association with HDL-C and ICH risk. We used principal component analysis to account for population structure and a Bonferroni-adjusted p<0.004 (12 tests) to declare statistical significance.

Results: The discovery phase included 1149 ICH cases (43% lobar hemorrhages) and 1238 controls. Twelve variants were nominally associated (p<0.05) with ICH, with the strongest association at the rs173539 locus (Figure 1: OR 1.25, 95%CI 1.11-1.41; p=6.0x10 -4 ) and no heterogeneity across studies (I 2 =0%). This association was replicated in 1625 cases (43% lobar hemorrhages) and 1845 controls (OR 1.12, 95%CI 1.02-1.24; p=0.03). A genetic score of independent CETP variants known to increase HDL-C by ~2.85 mg/dL was strongly associated with ICH risk (OR 1.86, 95%CI 1.44-2.40; p=1.4x10 -6 ).

Conclusion: Genetic variants in CETP associated with increased HDL-C raise the risk of ICH. Given ongoing therapeutic development in CETP inhibition and other HDL-raising strategies, further exploration of potential adverse cerebrovascular outcomes is warranted.

Abstract WP357: Prevalence of Pre- and Post-intracerebral Hemorrhage Sleep-disordered Breathing

Background: Sleep-disordered breathing (SDB) is an independent risk factor for stroke. The reported prevalence of SDB after stroke ranges from 60 to >70%, while the pre-stroke prevalence of SDB is less well described. Moreover, much of these data are derived from ischemic stroke or mixed ischemic stroke and intracerebral hemorrhage (ICH) cohorts. Studies that assess the prevalence of SDB before and after ICH are lacking, with only one prior study (n=32) that reported a post-ICH SDB prevalence of 78%. We report herein the results of a second, larger, prospective study that assessed the prevalence of pre- and post-ICH.

Methods: Participants enrolled in the population-based stroke surveillance study, the Brain Attack Surveillance in Corpus Christi (BASIC) project, with ICH from 2010-2015 were screened for SDB with the well validated ApneaLink Plus portable monitor (SDB defined as apnea-hypopnea index (AHI) ≥10). The Berlin questionnaire was administered, with reference to the pre-ICH state, to assess for possible pre-stroke SDB.

Results: Of the 60 ICH participants screened, the median age was 63 years (interquartile range (IQR): 55.5, 74.5). Twenty-one (35%) were female, 54 (90%) were Mexican American, and 53 (88%) had a history of hypertension. The median Glasgow Coma Scale score was 15.0 (IQR: 15.0, 15.0) and the median NIHSS was 5.5 (IQR: 1.5, 8.0). Post-ICH, the median AHI was 9.5 (IQR: 5.5, 19.0); almost half (46.7%) met criteria for SDB. Thirty-four participants (56.7%) screened as high risk for SDB pre-ICH.

Conclusion: Sleep-disordered breathing was highly prevalent after ICH, and also likely common before ICH, in this mostly Mexican American, community-based sample. If SDB increases risk for ICH, the findings suggest a potential new treatment target to prevent ICH and recurrent ICH.

Lymphocyte Subsets in the Adrenal Glands of Dogs With Primary Hypoadrenocorticism

Primary hypoadrenocorticism, or Addison's disease, is an autoimmune condition common in certain dog breeds that leads to the destruction of the adrenal cortex and a clinical syndrome involving anorexia, gastrointestinal upset, and electrolyte imbalances. Previous studies have demonstrated that this destruction is strongly associated with lymphocytic-plasmacytic inflammation and that the lymphocytes are primarily T cells. In this study, we used both immunohistochemistry and in situ hybridization to characterize the T-cell subtypes involved. We collected postmortem specimens of 5 dogs with primary hypoadrenocorticism and 2 control dogs and, using the aforementioned techniques, showed that the lymphocytes are primarily CD4+ rather than CD8+. These findings have important implications for improving our understanding of the pathogenesis and in searching for the underlying causative genetic polymorphisms.