Longitudinal hierarchical Bayesian models of covariate effects on airway and alveolar nitric oxide

Biomarkers such as exhaled nitric oxide (FeNO), a marker of airway inflammation, have applications in the study of chronic respiratory disease where longitudinal studies of within-participant changes in the biomarker are particularly relevant. A cutting-edge approach to assessing FeNO, called multiple flow FeNO, repeatedly assesses FeNO across a range of expiratory flow rates at a single visit and combines these data with a deterministic model of lower respiratory tract NO to estimate parameters quantifying airway wall and alveolar NO sources. Previous methodological work for multiple flow FeNO has focused on methods for data from a single participant or from cross-sectional studies. Performance of existing ad hoc two-stage methods for longitudinal multiple flow FeNO in cohort or panel studies has not been evaluated. In this paper, we present a novel longitudinal extension to a unified hierarchical Bayesian (L_U_HB) model relating longitudinally assessed multiple flow FeNO to covariates. In several simulation study scenarios, we compare the L_U_HB method to other unified and two-stage frequentist methods. In general, L_U_HB produced unbiased estimates, had good power, and its performance was not sensitive to the magnitude of the association with a covariate and correlations between NO parameters. In an application relating height to longitudinal multiple flow FeNO in schoolchildren without asthma, unified analysis methods estimated positive, statistically significant associations of height with airway and alveolar NO concentrations and negative associations with airway wall diffusivity while estimates from two-stage methods were smaller in magnitude and sometimes non-significant.

Hierarchical Bayesian estimation of covariate effects on airway and alveolar nitric oxide

Exhaled breath biomarkers are an important emerging field. The fractional concentration of exhaled nitric oxide (FeNO) is a marker of airway inflammation with clinical and epidemiological applications (e.g., air pollution health effects studies). Systems of differential equations describe FeNO—measured non-invasively at the mouth—as a function of exhalation flow rate and parameters representing airway and alveolar sources of NO in the airway. Traditionally, NO parameters have been estimated separately for each study participant (Stage I) and then related to covariates (Stage II). Statistical properties of these two-step approaches have not been investigated. In simulation studies, we evaluated finite sample properties of existing two-step methods as well as a novel Unified Hierarchical Bayesian (U-HB) model. The U-HB is a one-step estimation method developed with the goal of properly propagating uncertainty as well as increasing power and reducing type I error for estimating associations of covariates with NO parameters. We demonstrated the U-HB method in an analysis of data from the southern California Children’s Health Study relating traffic-related air pollution exposure to airway and alveolar airway inflammation.

Patterns and determinants of exhaled nitric oxide trajectories in schoolchildren over a 7-year period

Fractional exhaled nitric oxide (F _ENO50 ), a marker of allergic airway inflammation, is used in respiratory research and asthma clinical care; however, its trajectory with increasing age during childhood has not been well characterised. We examined F _ENO50 longitudinally during a period of important somatic growth to describe trajectories across childhood and adolescence in healthy participants and evaluate clinical factors as potential determinants of trajectories.F _ENO50 was collected at six visits over 8 years in a population-based cohort of 1791 schoolchildren without asthma (median age at entry 8.4 years). Smooth sex-specific F _ENO50 trajectories were estimated using generalised additive mixed models, with participant-level random effects. We evaluated whether sex-specific trajectories were influenced by race/ethnicity, body mass index (BMI) percentile, allergic rhinitis or puberty.Different F _ENO50 patterns were observed by sex in later childhood and several factors were associated with either F _ENO50 level or change in F _ENO50 as participants aged. F _ENO50 -age trajectories were similar by sex until age ∼11.5 years, after which males had greater F _ENO50 change than females. This divergence in F _ENO50 -age trajectories coincides with puberty. Males with higher starting BMI percentile had attenuated F _ENO50 -age slopes. Among males, F _ENO50 levels were lower in non-Hispanic white subjects. Among both sexes, participants with rhinitis had higher F _ENO50 F _ENO50 levels within individuals tracked over time; however, there was considerable variation in F _ENO50 patterns across participants.F _ENO50 trajectories from longitudinal data provide evidence of sex differences coinciding with puberty, suggesting potential hormone link. Improved understanding of determinants of F _ENO50 trajectories is needed to realise the potential for using individualised predicted F _ENO50 trajectories.

Impact of different fixed flow sampling protocols on flow-independent exhaled nitric oxide parameter estimates using the Bayesian dynamic two-compartment model

Exhaled nitric oxide (FeNO) is an established respiratory biomarker with clinical applications in the diagnosis and management of asthma. Because FeNO depends strongly on the flow (exhalation) rate, early protocols specified that measurements should be taken when subjects exhaled at a fixed rate of 50 ml/s. Subsequently, multiple flow (or "extended") protocols were introduced which measure FeNO across a range of fixed flow rates, allowing estimation of parameters including Caw NO and CA NO which partition the physiological sources of NO into proximal airway wall tissue and distal alveolar regions (respectively). A recently developed dynamic model of FeNO uses flow-concentration data from the entire exhalation maneuver rather than plateau means, permitting estimation of Caw NO and CA NO from a wide variety of protocols. In this paper, we use a simulation study to compare Caw NO and CA NO estimation from a variety of fixed flow protocols, including: single maneuvers (30, 50,100, or 300 ml/s) and three established multiple maneuver protocols. We quantify the improved precision with multiple maneuvers and the importance of low flow maneuvers in estimating Caw NO. We conclude by applying the dynamic model to FeNO data from 100 participants of the Southern California Children's Health Study, establishing the feasibility of using the dynamic method to reanalyze archived online FeNO data and extract new information on Caw NO and CA NO in situations where these estimates would have been impossible to obtain using traditional steady-state two compartment model estimation methods.

Sex-specific associations of autism spectrum disorder with residential air pollution exposure in a large Southern California pregnancy cohort

Autism spectrum disorder (ASD) affects more boys than girls. Recent animal studies found that early life exposure to ambient particles caused autism-like behaviors only in males. However, there has been little study of sex-specificity of effects on ASD in humans. We evaluated ASD risk associated with prenatal and first year of life exposures to particulate matter less than 2.5 μm in aerodynamic diameter (PM2.5) by child sex. This retrospective cohort study included 246,420 singleton children born in Kaiser Permanente Southern California (KPSC) hospitals between 1999 and 2009. The cohort was followed from birth through age five to identify 2471 ASD cases from the electronic medical record. Ambient PM2.5 and other regional air pollution measurements (PM less than 10 μm, ozone, nitrogen dioxide) from regulatory air monitoring stations were interpolated to estimate exposure during each trimester and first year of life at each geocoded birth address. Hazard ratios (HRs) were estimated using Cox regression models to adjust for birth year, KPSC medical center service areas, and relevant maternal and child characteristics. Adjusted HRs per 6.5 μg/m3 PM2.5 were elevated during entire pregnancy [1.17 (95% confidence interval (CI), 1.04-1.33)]; first trimester [1.10 (95% CI, 1.02-1.19)]; third trimester [1.08 (1.00-1.18)]; and first year of life [1.21 (95% CI, 1.05-1.40)]. Only the first trimester association remained robust to adjustment for other exposure windows, and was specific to boys only (HR = 1.18; 95% CI, 1.08-1.27); there was no association in girls (HR = 0.90; 95% CI, 0.76-1.07; interaction p-value 0.03). There were no statistically significant associations with other pollutants. PM2.5-associated ASD risk was stronger in boys, consistent with findings from recent animal studies. Further studies are needed to better understand these sexually dimorphic neurodevelopmental associations.

Antithrombotic Treatment at Onset of Stroke with Atrial Fibrillation, Functional Outcome, and Fatality: A Systematic Review and Meta-Analysis

Background

In atrial fibrillation–associated stroke, conflicting data exist regarding association between therapeutic vitamin K-antagonist anticoagulation (International Normalized Ratio 2–3) and early death and functional outcome, and few data exist relating to late outcome in ischemic and haemorrhagic atrial fibrillation–stroke.

Aim

We performed a systematic review and meta-analysis of oral anticoagulation at stroke onset, death and functional outcome.

Methods

We performed a systematic review, searching multiple sources. Studies were included if outcomes in atrial fibrillation–associated stroke were reported stratified by pre-stroke antithrombotic status, with documented International Normalized Ratio at onset. Outcomes were survival and good functional outcome (modified Rankin score 0–2) at discharge/30 days, and at one-year.

Results

Of eight studies (3552 patients) in ischemic stroke, International Normalized Ratio ≥ 2 compared with other treatments (International Normalized Ratio < 2, antiplatelet, or no anti-thrombotic) was associated with good outcome [pooled odds ratio 1·9 (95% confidence interval) 1·5–2·5, P < 0·001] and improved survival at 30 days discharge (pooled odds ratio for death 0·4, confidence interval 0·2–0·5, P < 0·001). The net benefit remained after inclusion of haemorrhagic stroke (odds ratio for good outcome 1·89, confidence interval 1·45–2·46, P < 0·001). At one-year, improved functional outcome for International Normalized Ratio ≥ 2 (pooled odds ratio 1·7, confidence interval 1·0–2·7, P = 0·04) and survival (odds ratio for death 0·5, confidence interval 0·4–0·8, P = 0·001) were also observed.

Conclusions

Therapeutic International Normalized Ratio at stroke onset was associated with early and late improved survival and functional recovery suggesting sustained benefit for warfarin anticoagulation for stroke outcome in atrial fibrillation patients. Long-term outcome data following stroke in patients taking new oral anticoagulants is required.

Serum uric acid and subsequent cognitive performance in patients with pre-existing cardiovascular disease

High serum uric acid (UA) levels are associated with numerous vascular risk factors, and vascular disease, that predispose patients to cognitive impairment, yet UA is also a major natural antioxidant and higher levels have been linked to slower progression of several neurodegenerative disease. In-order to test the association between UA and subsequent cognitive performance among patients that carry a high vascular burden, UA levels were determined by calorimetric enzymatic tests in a sub-cohort of patients with chronic cardiovascular disease who previously participating in a secondary prevention trial. After an average of 9.8±1.7 years, we assessed cognitive performance (Neurotrax Computerized Cognitive Battery) as well as cerebrovascular reactivity (CVR) and common carotid intima-media thickness (IMT). Among 446 men (mean age 62.3±6.4 yrs) mean UA levels were 5.8±1.1 mg/dL. Adjusted linear regression models revealed that low UA levels (bottom quintile) were associated with poorer cognitive performance. Adjusted differences between the bottom quintile and grouped top UA quintiles were (B coefficient±SE) −4.23±1.28 for global cognitive scores (p = 0.001), −4.69±1.81 for memory scores (p = 0.010), −3.32±1.43 for executive scores (p = 0.020) and −3.43±1.97 for visual spatial scores (p = 0.082). Significant difference was also found for attention scores (p = 0.015). Additional adjustment for impaired CVR and high common carotid IMT slightly attenuated the relationship. Stronger UA effect on cognitive performance was found for older (age>65) patients with significant age interaction for global cognitive score (p = 0.016) and for executive (p = 0.018) and attention domains (p<0.001). In conclusion, we demonstrate that low UA levels in patients with preexisting cardiovascular disease are associated with poorer cognitive function a decade later. These findings lend support to the hypothesis that oxidative stress may be involved in the pathogenesis of age-associated cognitive impairment.

Trends in antihypertensive treatment--lessons from the National Acute Stroke Israeli (NASIS) registry

BACKGROUND

Recent guidelines recommended different approaches to hypertension therapy. Our aim was to evaluate trends in blood pressure (BP) management among patients admitted with acute stroke over the past decade.

METHODS

The study population comprised 6279 consecutive patients, admitted with an acute stroke, and included in a national registry of three consecutive periods conducted during the years 2004-2010. We compared patients' characteristics and temporal trends of antihypertensive therapy utilization before hospital admission.

RESULTS

Among 4727 hypertensive patients, 3940 (83%) patients have taken antihypertensive drug therapy - 1430 (30.2%) a single agent, 1500 (31.7%) two agents and 1010 (21.4%) three or more antihypertensive agents. The most common class used was renin-angiotensin system (RAS) blockers (n = 2575; 54%) followed by beta-blockers (n = 2033; 43%). The same pattern was observed in patients treated with monotherapy. The use of RAS blockers and beta-blockers has increased over the years (p < 0.001 for both), whereas the use of diuretics decreased and the use of calcium antagonists remained stable. Among those who were treated with a single agent, the use of diuretics and calcium antagonists decreased and the use of RAS blockers increased, whereas the use of beta-blockers remained unchanged.

CONCLUSIONS

RAS blockers and beta-blockers are the most common antihypertensive agents used in Israel. Over time, the use of RAS blockers and beta-blockers has increased, whereas the use of diuretics decreased.

Abstract T P159: Cardiovascular Health and Subsequent Cognitive Function in Patients with Pre-existing Coronary Heart Disease

Background: Cardiovascular (CV) health factors are associated with lower risk of CV disease, stroke and all-cause mortality. We used a CV health metric in order to examine association with subsequent cognitive function.

Methods: A subset of patients with coronary heart disease (CHD) that participated in the secondary prevention BIP trial were assessed for cognitive function (Mindstream Computerized Cognitive Battery) after an average of 9.8 ±1.7 years. A CV health metric at baseline was calculated including 3 health factors (glucose, LDL cholesterol, and blood pressure), 4 health behaviors (BMI, physical activity, adherence to a Mediterranean diet, and cigarette smoking), and one marker assessing in-part early life environment (body height), categorizing each of these 8 factors into ideal (2 points), intermediate (1 point), and poor levels (0 points).

Results: Among 310 patients (mean age 62 yrs, 96.5% men) higher CV health scores were positively associated with educational level (p<0.001) and inversely with age (p=0.003), while no significant associations were identified with ultrasound indices of cerebrovascular disease (impaired CVR, increased common carotid IMT and carotid plaques). In linear regression models adjusted for age, educational level, sex and BIP study arm, increment in the overall CV health score (per 1 point) was associated with higher scores in executive function (p=0.002), memory (p=0.06), visuospatial function (p=0.005), attention (p=0.024) as well as in a global cognitive function score [B coefficient ± SE, 1.19±0.35 (p=0.001)] assessed a decade later. Increment (per 1-point) in the health behavior component was associated with 1.28±0.49 (p=0.009) higher cognitive score, in the early life environment component with 2.55±0.75 (p=0.001) higher cognitive score, while the health factors component was not associated with subsequent cognitive scores [0.24±0.52 (p=0.64)]. In sensitivity analyses excluding patients with stroke similar findings were observed.

Conclusion: Among patients with pre-existing CHD, better CV health is associated with subsequent higher cognitive functions. Our findings suggest that health behavior and early life environment are important determinants of late-life cognitive function.

Cumulative exposure to particulate matter air pollution and long-term post-myocardial infarction outcomes

INTRODUCTION

Chronic environmental exposure to particulate matter <2.5μm in diameter (PM2.5) has been associated with cardiovascular disease; however, the effect of air pollution on myocardial infarction (MI) survivors is not clear. We studied the association of chronic exposure to PM2.5 with death and recurrent cardiovascular events in MI survivors.

METHODS

Consecutive patients aged ≤65years admitted to all medical centers in central Israel after first-MI in 1992-1993 were followed through 2005 for cardiovascular events and 2011 for survival. Data on sociodemographic and prognostic factors were collected at baseline and during follow-up. Residential exposure to PM2.5 was estimated for each patient based on data recorded at air quality monitoring stations. Cox and Andersen-Gill proportional hazards models were used to study the pollution-outcome association.

RESULTS

Among the 1120 patients, 469 (41.9%) died and 541 (48.3%) experienced one or more recurrent cardiovascular event. The adjusted hazard ratios associated with a 10μg/m(3) increase in PM2.5 exposure were 1.3 (95% CI 0.8-2.1) for death and 1.5 (95% CI 1.1-1.9) for multiple recurrences of cardiovascular events (MI, heart failure and stroke).

CONCLUSION

When adjustment for socio-demographic factors is performed, cumulative chronic exposure to PM2.5 is positively associated with recurrence of cardiovascular events in patients after a first MI.

The LRRK2 G2019S mutation status does not affect the outcome of subthalamic stimulation in patients with Parkinson's disease

BACKGROUND

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an established therapy for advanced Parkinson's disease (PD). The most common genetic mutation associated with PD identified to date is the G2019S mutation of the LRRK2 gene, which is highly prevalent in the Ashkenazi Jewish population. The effect of STN-DBS surgery in patients carrying this mutation has not been systematically studied. We therefore performed a case-control study to evaluate the impact of the G2019S mutation status on the outcomes of bilateral STN-DBS.

METHODS

The study sample included 39 Jewish PD patients with bilateral STN-DBS. Thirteen patients (5 females) were G2019S mutation heterozygous. The control group consisted of 26 PD patients with bilateral STN-DBS, negative for the mutation, matched (2:1) for gender, age at PD onset, and disease duration at surgery. Clinical data including the Unified PD Rating Scale scores (UPDRS), levodopa equivalent daily dose (LEDD), and clinical global impression of change (CGIC) concerning both motor and neuropsychiatric outcome- were available at 3 time points (preoperative baseline, 6-12 months and 3 years postoperatively).

RESULTS

Implementing a linear mixed model, a significant improvement (p < 0.05) was found for the whole group concerning reduction in motor UPRDS (off state) and LEDD pre- vs. postoperatively, as expected. No difference in clinical outcome was found between carriers and matched non-carriers at baseline or at postoperative follow-up (up to 3 years).

CONCLUSIONS

In our study, STN-DBS outcomes were not influenced by the LRRK2 G2019S mutation, and thus knowledge of carrier status may not be relevant to the considerations of patient selection for surgery.

Quantitative detection of thrombin activity in an ischemic stroke model

Thrombin, a central factor in thrombogenesis, affects cells in the brain through protease activated receptors. Low levels of thrombin activity are neuroprotective while higher levels are deleterious, and we have therefore developed a new method for its direct quantitative measurement in brain slices following stroke. Thrombin activity was measured by a fluorescent substrate on fresh coronal slices taken from the ipsilateral and contralateral hemispheres 24-72 h following permanent right middle cerebral artery occlusion. Prolyl endopeptidase and aminopeptidases were inhibited as a critical step to insure the specificity of the assay for thrombin detection. Infarct volume was assessed using TTC staining. Thrombin activity in the right ischemic hemisphere was significantly higher compared to the contralateral hemisphere (32 ± 6 and 27 ± 10 mU/ml, mean ± SE in the two most affected slices from the ischemic hemisphere vs. 21 ± 6 and 8 ± 2 mU/ml in corresponding contralateral slices; p < 0.05). Thrombin levels in the ischemic and contralateral hemispheres were significantly higher compared to healthy control mice and were above the range known to be protective to brain cells. A significant correlation was found between thrombin activity in the ischemic hemisphere and the infarct volume. Results of studies based on this method may translate into potential thrombin based therapies.

Is the evaluation and treatment of transient ischemic attack performed according to current knowledge? A nationwide Israeli registry

BACKGROUND

Patients with transient ischemic attack (TIA) at a high risk of stroke can be identified and should be managed urgently.

OBJECTIVES

To investigate whether recognized recommendations are being implemented in Israel.

METHODS

An Israeli nationwide registry (NASIS) on patients admitted with stroke and TIA was conducted in all acute care hospitals within 2 successive months during 2004, 2007 and 2010. A revised ABCD2 score was applied retrospectively. Patients with TIA were divided into a low risk group (LRG, 0-3 points) and a high risk group (HRG, 4-6 points) and were compared to patients with minor ischemic strokes (MIS, NIHSS score < or = 5 points).

RESULTS

A total of 3336 patients were included (1023 with TIA: LRG 484, HRG 539, and MIS 2313). LRG patients were younger and had lower rates of most traditional risk factors as compared with HRG and MIS patients. Brain imaging was performed in almost all the patients. Ancillary tests (vascular and cardiac) were overall underused, yet were performed more in LRG (53.2% and 26.9% respectively) than in HRG patients (41.6%, 18.9%). Between periods there was no change in usage of ancillary tests for the LRG and a modest increase in both HRG and MIS patients. For performance of vascular investigations overall, the odds ratio was 1.69 (95% confidence interval 1.42-2.00) comparing 2010 with 2004, but 0.7 (95% CI 0.5-0.9) comparing HRG with LRG. Between periods an increase in statin usage was observed in all groups (OR 2.69, 95% CI 2.25-3.21) but was more marked in MIS patients (OR 3.06, 95% CI 2.47-3.8).

CONCLUSIONS

The approach to TIA risk stratification and management in Israeli hospitals does not follow standards set by current guidelines. Standardized protocols for TIA should be used to assure effective management.

Perceived hardships at midlife: prediction of long-term stroke mortality

OBJECTIVES

The objective of this study is to examine the association between perceived hardships and long-term stroke mortality among a large cohort of middle-aged men.

BACKGROUND

Unlike cardiovascular morbidity and mortality, much less is known about the relationship between psychosocial factors and risk of stroke.

METHODS

A cohort of 10,059 men aged ≥ 40 years at study inclusion that were tenured civil servants or municipal employees were followed for mortality over a median of 28.1 years (IQR 18.9-34.3). During follow-up 6528 (64.9%) men died, 665 of stroke and 1769 of coronary heart disease (CHD). A composite score of perceived hardships was calculated based on a structured psychosocial questionnaire filled at baseline, assessing domains of work, family, and finance. Cox proportional hazard models were used adjusting for traditional risk factors and socio-economic status.

RESULTS

At baseline, subjects with higher hardship scores were slightly older, smoked more cigarettes, had higher prevalence of CHD, lower systolic blood pressure, higher anxiety levels and lower socio-economic status. Compared with the bottom tertile, the middle (HR 1.26, 95% CI 1.04-1.53) and top tertiles of the hardship score (HR 1.33, 95% CI 1.07-1.64) exhibited higher risk of stroke mortality (P for trend=0.008), while no significant association was found with long-term mortality from CHD. The magnitude of the association was comparable to that of diabetes (HR 1.30, 95% CI 1.02-1.66).

CONCLUSION

Perceived hardships measured at midlife in a large cohort of apparently healthy men independently predict stroke mortality over long-term follow-up.

Recovery of self-rated health as a predictor of recurrent ischemic events after first myocardial infarction: a 13-year follow-up

OBJECTIVE

Following the trajectory hypothesis for the validity of self-rated health (SRH), we tested whether subjective recovery of health, that is, return to the same or higher level of SRH after a major health event, independently predicts better long-term prognosis.

METHODS

Participants were 640 patients (≤ 65 years) admitted to the eight medical centers in central Israel with incident MI in a 1-year period (mean age 54, 17% female). Baseline data were collected within days of the index MI. SRH in the preceding year was assessed at baseline, and current SRH was assessed 3-6 months later. Recurrent ischemic events (recurrent MI, hospitalization with unstable angina pectoris, or cardiac death) were recorded during a mean follow-up of 13 years.

RESULTS

A reduced risk of recurrent events was associated with an upward change of one level (e.g., from 3 at T1 to 4 at T2) in SRH (HR = 0.76, 95%CI: 0.69-0.85), controlling for baseline retrospective SRH. Risk was still significantly lower for each unit of improvement after adjusting for sociodemographics, preevent comorbidity, cardiac risk factors, MI severity, and early post-MI events (HR = 0.85, 95% CI 0.75-0.95).

CONCLUSIONS

Individuals who perceived themselves 3-6 months after a first MI to be healthier than they had been in the year preceding the MI were more likely to survive event-free throughout the next 13 years, controlling for baseline retrospective SRH and multiple cardiac risk factors. Failure to experience such subjective recovery of one's health is a serious risk factor, which indicates that SRH should be monitored regularly after a MI.

The relatively good outcome of cerebellum-brainstem ischemic strokes

BACKGROUND

Our clinical experience suggests that the outcome of cerebellum-brainstem ischemic strokes is better than that of hemispheric ischemic strokes.

METHODS

Within the setting of 2 national Israeli prospective stroke surveys, we analyzed risk factors, etiology, severity at presentation, and prognosis of first ischemic cerebellum-brainstem stroke (259 patients), comparing with strokes within the anterior circulation (1,029 patients).

RESULTS

Patients with cerebellum-brainstem strokes were younger and had less frequently atrial fibrillation and congestive heart failure. Cardioembolic etiology was significantly less prevalent (p < 0.001). Severity at presentation was milder (p < 0.001). At discharge, worsening of the modified Rankin Scale was present in a smaller number of patients (p < 0.001); more returned to their home (p < 0.001). Six-month and 1-year mortality were lower (p < 0.001 for both). Adjusted logistic regression models showed that patients with cerebellum-brainstem strokes had 50% smaller chances of dying (OR 0.55; 95% CI 0.31-0.98) and a smaller chance of worsening of the modified Rankin Scale at discharge (OR 0.61; 95% CI 0.46-0.82).

CONCLUSIONS

Cerebellum-brainstem strokes are less frequently cardioembolic, have a less severe presentation, and carry a better immediate and long-term prognosis.

The frontal assessment battery as a tool for evaluation of frontal lobe dysfunction in patients with Parkinson disease

BACKGROUND

Frontal-type cognitive deficits are common in patients with Parkinson disease (PD). The Frontal Assessment Battery (FAB) was developed to assess frontal lobe functions. However, many studies found that it also correlated with a variety of other general neuropsychological tests.

OBJECTIVES

To evaluate whether the FAB has an added value over the Mini-Mental State Examination (MMSE) and other bedside neuropsychological tests in reflecting cognitive deficits in patients with PD.

METHODS

Seventy-two consecutive patients with PD underwent cognitive assessment including the FAB, the MMSE, and a variety of other neuropsychological tests. Correlations were examined using the Spearman's r.

RESULTS

Highly significant correlations were found between the total FAB score and tests of attention, executive functions, and memory. To evaluate the contribution of the FAB beyond that of the MMSE, partial correlation was used. Analyses revealed that the FAB still correlated with most of the tests. Dividing the patients according to the median MMSE score revealed that the high correlation between the FAB and the MMSE was preserved in the low MMSE group, while in the high MMSE group the correlation was relatively low. In the high MMSE group, the FAB correlated with 11 tests compared to the MMSE that correlated with one (P < .001), while in the low MMSE group the number of correlations was 13 versus 7, respectively (P = .05).

CONCLUSIONS

In our sample of patients with PD, the FAB correlated with dysfunction in a variety of cognitive domains including attention, memory, and executive functions. The FAB has an added value over the MMSE, particularly among nondemented patients, an advantage that can be used in clinical practice.

Abstract 3332: Common Carotid Intima Media Thickness, Carotid Plaque and Cognitive Performance in Patients with Atherosclerotic Disease

Background - Patients with atherothrombotic disease are prone to cognitive impairment. We tested whether high common carotid intima-media thickness (CC-IMT) and bilateral carotid plaques among patients with long lasting CHD are associated with poorer cognitive scores.

Methods - Patients with CHD previously included in a secondary prevention trial were assessed after a period of 15±3 years for cognitive performance (Mindstream Computerized Cognitive Battery), for CC-IMT (M’Ath®-Std, Metris) and for carotid plaque using ultrasound (HDI 5000 SonoCT, Philips). We compared cognitive scores in patients with and without high CC-IMT values (top quartile of CC- IMT; >1.06 mm) and in patients with and without high CC-IMT and bilateral carotid plaques.

Results - Among 448 non-demented patients (mean age 71.8±6.1 yrs, 96% men) mean±SD CC-IMT was 0.97±0.17 and 54.7% had bilateral carotid plaques. Linear regression models ( Table ) adjusted for age, sex, education, BMI, smoking, diabetes and hypertension (Model 1) demonstrated that high CC-IMT and presence of high CC-IMT and carotid plaques were associated with lower cognitive scores. Additional adjustment for history of stroke and impaired cerebrovascular reactivity (Model 2) resulted in similar effects. Associations were only slightly altered after exclusion of patients with history of stroke.

Conclusion - Among non-demented patients with long lasting CHD, high CC- IMT and presence of high CC-IMT and carotid plaques are associated with lower cognitive performance particularly in the executive function domain.

Cerebral artery calcification in patients with acute cerebrovascular diseases: determinants and long-term clinical outcome

BACKGROUND AND PURPOSE

Coronary artery calcium is an independent predictor of all-cause mortality. We sought to examine the determinants of intracranial cerebral artery calcification (CAC) and its association with long-term outcome in a large prospective cohort of stroke patients.

METHODS

Consecutive patients hospitalized because of acute stroke (ischaemic and intracerebral hemorrhage) or TIA throughout a large medical center were systematically assessed and followed up for 1 year. Intracranial CAC was assessed from baseline brain CT blinded to clinical data. Patients were categorized to no, mild, and severe CAC according to their total CAC score. Determinants of CAC were studied with logistic regression analysis. Risk of death, Barthel Index ≤ 60 or death and living in a nursing facility or death were assessed.

RESULTS

  Amongst 1049 patients (mean age: 70 ± 13 years, 59% males) CAC was present in 727 (69%) patients. The main determinants of CAC were increasing age (OR 1.4, 95% CI 1.3-1.6, per 5 years), diabetes (OR: 2.1, 1.4-3.0), smoking (1.4, 1.0-2.2), hypertension (1.4, 1.0-2.1), and prior coronary heart disease (1.9, 1.3-2.9). CAC was associated with mortality and poor outcome amongst patients with ischaemic stroke; however, after adjusting for age and stroke severity, no significant association was observed. In patients with intracerebral hemorrhage, outcomes were not related to CAC.

CONCLUSIONS

  Intracranial CAC is highly prevalent in patients with acute stroke and its main determinants are older age, diabetes, smoking, hypertension, and prior coronary heart disease. Associations between CAC and mortality or poor functional outcome in the first year after ischaemic stroke are mainly age- and stroke severity-driven.

Off-hours admission for acute stroke is not associated with worse outcome--a nationwide Israeli stroke project

BACKGROUND AND PURPOSE

Several studies reported worse outcome for stroke patients arriving on weekends. We compared working hours to off-work hours throughout the week as there is lack of experienced staff and special services during off-hours.

METHODS

A nationwide stroke survey project on acute stroke was carried out in all acute care hospitals in Israel during 2004, 2007 and 2010 (2-month each). 'On-hours' were defined as regular Israel working hours and the rest, including holidays, were defined as 'off-hours'. The modified Rankin scale (mRS) at discharge was used for the main analysis on outcome.

RESULTS

A total of 4827 acute strokes patients were analyzed (2139 arrived on-hours and 2688 during off-hours). 'Off-hours' patients were 1 year younger (mean 70 vs. 71 years in 'on-hours') had lower rates of prior cardiac interventions, but had higher admission blood pressure levels and had more intracerebral hemorrhages (ICH) (11% vs. 8% in 'on-hours' patients, P < 0.001). Death during hospitalization was recorded in 9% of 'off-hours' vs. 6% of 'on-hours' patient (P = 0.004). Controlling for age, blood pressure, stroke type, pre-stroke mRS, admission NIHSS, and thrombolysis, the relative odds of poor outcome (i.e. mRS ≥ 2) amongst 'off-hours' admissions compared to on-hours was 1.09 (95% CI: 0.92-1.30). Odds ratio amongst ischaemic stroke patients was 1.08 (95% CI: 0.88-1.33).

CONCLUSIONS

Off-hours stroke admissions were associated with higher short-term mortality rate, probably due to a higher rate of ICH. After controlling for the latter and other potential confounders, 'off-hours' admissions were not different from 'on-hours' with respect to poor outcome.

Ethnic variations in acute ischemic stroke: findings from the National Acute Stroke Israeli Survey (NASIS)

BACKGROUND

We intended to determine ethnic differences in the characteristics, management and outcome of acute ischemic stroke between the Israeli Arab and Jewish populations.

METHODS

A national survey was conducted in 2004 at all 28 hospitals in Israel. Information on demographics, transportation, risk factors, clinical presentation, stroke severity, type and subtype, management and clinical outcome was obtained. Mortality during the 36 months after hospitalization was assessed by matching with national mortality data.

RESULTS

Of the 1,540 patients, 169 (11%) were Arabs and 1,371 (89%) were Jews. The mean age of Arab patients was 9 years younger than in Jewish patients (63 ± 11 vs. 72 ± 12 years). Also, Arabs were more likely to be obese (OR = 1.72; 95% CI: 1.19-2.50) and have diabetes (OR = 1.41; 95% CI: 1.01-1.96), while Jews were more likely to have dyslipidemia (OR = 1.56; 95% CI: 1.11-2.17). A greater percentage of the Arab patients arrived at the hospital independently (OR = 3.85; 95% CI: 2.56-5.56) and were less likely to arrive within 3 h of symptom onset (OR = 2.33; 95% CI: 1.39-3.85). Arabs suffered increased rates of lacunar stroke (OR = 1.67; 95% CI: 1.14-2.43) and were discharged home more often (OR = 2.40; 95% CI: 1.35-4.25). No differences in severity of stroke, management, complications, disability or mortality were found between the 2 groups.

CONCLUSIONS

The unique characteristics of the Arab and Jewish populations should be considered when planning stroke-care services and culturally oriented public education programs.

Chronic kidney disease in patients with acute intracerebral hemorrhage: association with large hematoma volume and poor outcome

BACKGROUND

Chronic kidney disease (CKD) is associated with both a risk of adverse vascular outcome and a risk of bleeding. We have tested the hypothesis that in the setting of an acute intracerebral hemorrhage (ICH), CKD is associated with poor outcome and with larger hematoma volume.

METHODS

We examined the association between CKD and ICH characteristics and outcome within a prospective cohort study of consecutive patients hospitalized with an acute stroke and followed for 1 year. CKD was categorized by the estimated baseline glomerular filtration rate into moderate/severe impairment (<45), mild impairment (45-60) and no impairment (>60 ml/min/1.73 m(2)).

RESULTS

Among 128 patients with an ICH (mean age = 71.7 ± 12.3 years, 41.4% women) 46.1% had CKD (23.4% mild and 22.7% moderate/severe). Patients with moderate/severe impairment had >4-fold adjusted hazard ratio for mortality over 1 year (4.29; 95% CI = 1.69-10.90) compared to patients with no impairment. The hematoma volumes [median (25-75%)] were 15.3 ml (5.4-37.5) in patients with no impairment, 16.6 (6.8-36.9) in mild impairment and 50.2 (10.4-109.1) in moderate/severe impairment (p = 0.009). The location of the hematoma was lobar in 12% with no impairment, 17% with mild impairment and 39% with moderate/severe impairment (p = 0.02). Patients with moderate/severe impairment exhibited a 2.3-fold higher hematoma volume (p = 0.04) and a >6-fold higher odds of lobar location (95% CI = 1.59-24.02) as compared to no impairment. Further adjustment for antiplatelet use and for presence of leukoaraiosis attenuated the association with hematoma volume (p = 0.15), while moderate/severe impairment was associated with an adjusted OR of 5.35 (95% CI = 1.18-24.14) for lobar location.

CONCLUSIONS

Presence of moderate/severe CKD among patients with ICH is associated with larger, lobar hematomas and with poor outcome.

Serum calcium levels and long-term mortality in patients with acute stroke

BACKGROUND

Calcium concentrations in serum are maintained within an exquisitely narrow range. Our aim was to examine the association between serum calcium and albumin-adjusted calcium (calcium(adj)) levels and stroke outcome in a cohort of unselected patients with acute stroke.

METHODS

Consecutive patients hospitalized due to acute stroke (ischemic or intracerebral hemorrhage) throughout a large medical center were systematically assessed and followed for 1 year. Baseline total calcium and calcium(adj) levels were collapsed into groups of low (<8.6 mg/dl), normal (8.7-9.9 mg/dl) and high (>10 mg/dl) levels and linear and quadratic relations with outcome were examined.

RESULT

Among 784 patients (mean age 70.7 ± 12.5 years, 42.5% females), the mean ± SD total calcium level was 9.3 ± 0.6 mg/dl. For total calcium, the adjusted hazard ratio (HR) for all-cause death over 1 year was 1.83 [95% confidence interval (CI) 1.22-2.75] among patients with low versus normal levels. For calcium(adj), the adjusted HR for all-cause death among women was over 3-fold higher among patients with high calcium(adj) levels versus those with normal levels (3.31; 95% CI 1.70-6.46), while no such associations were observed among men. In models developed to estimate the linear and quadratic relations, each unit increment in total calcium squared was associated with an increased adjusted HR of all-cause death over 1 year (p = 0.02) confirming nonlinear associations, and each unit increment in calcium(adj) squared was associated with an increased adjusted HR of all-cause death over 1 year among women (p < 0.001) but not among men (p = 0.70).

CONCLUSIONS

Serum calcium concentrations are a marker of mortality in acute stroke patients, but the associations are not linear, increasing at both extremes of calcium levels. Our findings suggest that long-term survival is optimal in a distinct range of serum calcium levels.

Ischemic stroke due to acute basilar artery occlusion: proportion and outcomes

BACKGROUND

Multiple case series, mostly highly selected, have demonstrated a very high mortality following acute basilar artery occlusion. The more widespread availability and use of non-invasive vascular imaging over recent years has increased the rate of ABAO diagnosis.

OBJECTIVES

To estimate the proportion of diagnosed ABAO among all-cause ischemic stroke in an era of increasing use of non-invasive vascular imaging and to compare the characteristics and outcomes between these two groups.

METHODS

We compared 27 consecutive cases of ABAO identified in a university hospital between 2003 and 2007 with 311 unselected cases of ischemic stroke from two 4 month surveys.

RESULTS

ABAO diagnosis increased from 0.3% of all-cause ischemic stroke (2003-2004) to 1.1% (2007), reflecting the increased use of non-invasive vascular imaging. In comparison to all-cause ischemic stroke, ABAO patients were younger (mean age 60 vs. 71 years), were more likely to be male (89% vs. 60%), had less atrial fibrillation (7% vs. 26%), more severe strokes (baseline NIHSS over 20: 52% vs. 12%), higher admission white cell count (12,000 vs. 9000 cells/ mm3), lower admission systolic blood pressure (140 +/- 24 vs. 153 +/- 27 mmHg), higher in-hospital mortality rates (30% vs. 8%) and worse functional outcome (modified Rankin scale < or = 3, 22% vs. 56%) (P< 0.05 for all). Rates of reperfusion therapy for ABAO increased from 0 in 2003-2004 to 60% in 2007.

CONCLUSIONS

In this study, ABAO patients represented approximately 1% of all-cause ischemic stroke and were about a decade younger than patients with all-cause ischemic stroke. We report a lower ABAO mortality compared to previous more selected case series; however, most survivors had a poor functional outcome. Given the marked clinical heterogeneity of ABAO, a low threshold for non-invasive vascular imaging with a view to definitive reperfusion treatment is needed.

Anemia status, hemoglobin concentration and outcome after acute stroke: a cohort study

BACKGROUND

In the setting of an acute stroke, anemia has the potential to worsen brain ischemia, however, the relationship between the entire range of hemoglobin to long-term outcome is not well understood.

METHODS

We examined the association between World Health Organization-defined admission anemia status (hemoglobin<13 in males, <12 g/dl in women) and hemoglobin concentration and 1-year outcome among 859 consecutive patients with acute stroke (ischemic or intracerebral hemorrhage).

RESULTS

The mean baseline hemoglobin concentration was 13.8 +/- 1.7 g/dl (range 8.1 - 18.7). WHO-defined anemia was present in 19% of patients among both women and men. After adjustment for differences in baseline characteristics, patients with admission anemia had an adjusted OR for all-cause death at 1-month of 1.90 (95% CI, 1.05 to 3.43) and at 1-year of 1.72 (95% CI, 1.00 to 2.93) and for the combined end-point of disability, nursing facility care or death of 2.09 (95% CI, 1.13 to 3.84) and 1.83 (95% CI, 1.02 to 3.27) respectively. The relationship between hemoglobin quartiles and all-cause death revealed a non-linear association with increased risk at extremes of both low and high concentrations. In logistic regression models developed to estimate the linear and quadratic relation between hemoglobin and outcomes of interest, each unit increment in hemoglobin squared was associated with increased adjusted odds of all-cause death [at 1-month 1.06 (1.01 to 1.12; p = 0.03); at 1-year 1.09 (1.04 to 1.15; p < 0.01)], confirming that extremes of both low and high levels of hemoglobin were associated with increased mortality.

CONCLUSIONS

WHO-defined anemia was common in both men and women among patients with acute stroke and predicted poor outcome. Moreover, the association between admission hemoglobin and mortality was not linear; risk for death increased at both extremes of hemoglobin.