Stroke risk factors and outcomes among various Asian ethnic groups in Singapore

Stroke Demographics, Risk Factors, Subtypes, Syndromes, Mechanisms and Inter-Ethnic Differences between Chinese, Malays and Indians in Singapore-A Hospital-Based Study

Disparities in stroke may be due to socioeconomics, demographics, risk factors (RF) and ethnicity. Asian data are scant. This retrospective hospital-based study aimed to explore demographics, RF, stroke subtypes and mechanisms among the Chinese, Malays and Indians in Singapore. Stroke was subtyped into haemorrhagic stroke (HS) and ischaemic stroke (IS). For IS, the clinical syndrome was classified using the Oxfordshire Community Stroke Project (OCSP) classification while the stroke mechanism was categorised using the Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification. During the study period 1 June 2015 to 31 December 2023, data were collected on 1165 patients, with a mean age of 65.6 ± 12.9 yr; 47.4% were female, 83% were Chinese and hypertension (63.5%) and hyperlipidaemia (60.3%) were the most common RF. HS comprised 23.5% (95%CI 21.1-26.1%) (intracerebral 21.7%, subarachnoid 1.3%) of the patients, while IS comprised 76.5% (95%CI 73.9-78.9%) (small artery occlusion 29.0%, cardioembolism 13.3%, large artery atherosclerosis 9.4%, stroke of other determined aetiology 6.2%, stroke of undetermined aetiology 18.6%); 55% of patients had lacunar syndrome. A multivariable analysis showed that HS was associated with ethnicity (p = 0.044), diabetes mellitus (OR 0.27, 95%CI 0.18-0.41, p < 0.001) and smoking (OR 0.47, 95%CI 0.34-0.64, p < 0.001). There were no significant inter-ethnic differences by the OCSP (p = 0.31) or TOAST (p = 0.103) classification. While differences in stroke subtype in Asia may be due to RF, ethnicity has a role. More studies are needed to further explore this.

Stroke in Asia

BACKGROUND

There is a significant burden of stroke in Asia. Asia has the largest population in the world in 2023, estimated at 4.7 billion. Approximately 9.5-10.6 million strokes will be anticipated annually in the backdrop of a diverse group of well-developed and less developed countries with large disparities in stroke care resources. In addition, Asian countries are in varying phases of epidemiological transition.

SUMMARY

In this review, we examined recent epidemiological features of ischaemic stroke and intracerebral haemorrhage in Asia with recent developments in hyperacute stroke reperfusion therapy and technical improvements in intracerebral haemorrhage. The article also discussed the spectrum of cerebrovascular diseases in Asia, which include intracranial atherosclerosis, intracerebral haemorrhage, infective aetiologies of stroke, moyamoya disease, vascular dissection, radiation vasculopathy, and cerebral venous thrombosis.

KEY MESSAGES

The review of selected literature and recent updates calls for attention to the different requirements for resources within Asia and highlights the breadth of cerebrovascular diseases still requiring further research and more effective therapies.

Epidemiology, Pathophysiology, and Imaging of Atherosclerotic Intracranial Disease

Intracranial atherosclerotic disease (ICAD) is one of the most common causes of stroke worldwide. Among people with stroke, those of East Asia descent and non-White populations in the United States have a higher burden of ICAD-related stroke compared with Whites of European descent. Disparities in the prevalence of asymptomatic ICAD are less marked than with symptomatic ICAD. In addition to stroke, ICAD increases the risk of dementia and cognitive decline, magnifying ICAD societal burden. The risk of stroke recurrence among patients with ICAD-related stroke is the highest among those with confirmed stroke and stenosis ≥70%. In fact, the 1-year recurrent stroke rate of >20% among those with stenosis >70% is one of the highest rates among common causes of stroke. The mechanisms by which ICAD causes stroke include plaque rupture with in situ thrombosis and occlusion or artery-to-artery embolization, hemodynamic injury, and branch occlusive disease. The risk of stroke recurrence varies by the presumed underlying mechanism of stroke, but whether techniques such as quantitative magnetic resonance angiography, computed tomographic angiography, magnetic resonance perfusion, or transcranial Doppler can help with risk stratification beyond the degree of stenosis is less clear. The diagnosis of ICAD is heavily reliant on lumen-based studies, such as computed tomographic angiography, magnetic resonance angiography, or digital subtraction angiography, but newer technologies, such as high-resolution vessel wall magnetic resonance imaging, can help distinguish ICAD from stenosing arteriopathies.

Prevalence and Factors Associated with Atrial Fibrillation in Patients with Transient Ischemic Attack or Ischemic Stroke in Northern Vietnam

BACKGROUND

The prevalence and risk factors of atrial fibrillation (AF) in patients with transient ischemic attack (TIA) or ischemic stroke in Northern Vietnam are not well understood. This study aimed to estimate the prevalence and identify factors associated with AF in this population.

METHODS

A cross-sectional study was conducted on 2038 consecutive patients with TIA or ischemic stroke admitted to Bach Mai Hospital. AF was diagnosed using an electrocardiogram or Holter monitor. Logistic regression analyses were performed to determine the association between AF and risk factors.

RESULTS

Among the patients, 18.1% (95% CI: 16.46 to 19.85) had AF. Older age, renal dysfunction, valvular heart disease (VHD), and low ejection fraction were significantly associated with AF. Advanced age (per 10 years) (adjusted OR, aOR 1.39; 95% CI, 1.23 to 1.57), estimated glomerular filtration ratio decrease (per 10 mL/min/1.73 m2) (aOR 1.12; 95% CI, 1.06 to 1.17), VHD (aOR 9.59; 95% CI, 7.10 to 12.95), and low ejection fraction (<50%) (aOR 2.61; 95% CI, 1.62 to 4.21) had notable odds ratios for AF.

CONCLUSIONS

Atrial fibrillation is prevalent among patients with TIA or ischemic stroke in Northern Vietnam, surpassing rates in other Southeast Asian countries. Age, renal dysfunction, VHD, and low ejection fraction were significant risk factors for AF in this population.

Etiologies, mechanisms, and risk factors of ischemic stroke in a young Asian adult cohort

OBJECTIVES

Risk factors and causes of acute ischemic stroke (AIS) are more diverse in young adults, and traditional stroke classifications may be inadequate. Precise characterisation of AIS is important for guiding management and prognostication. We describe stroke subtypes, risk factors and etiologies for AIS in a young Asian adult population.

MATERIALS AND METHODS

Young AIS patients aged 18-50 years admitted to two comprehensive stroke centres from 2020-2022 were included. Stroke etiologies and risk factors were adjudicated using Trial of Org 10172 in Acute Stroke Treatment (TOAST) and International Pediatric Stroke Study (IPSS) risk factors. Potential embolic sources (PES) were identified in a subgroup with embolic stroke of undetermined source (ESUS). These were compared across sex, ethnicities and age groups (18-39 years versus 40-50 years).

RESULTS

A total of 276 AIS patients were included, with mean age 43±5.7 years and 70.3% male. Median duration of follow-up was 5 months (IQR: 3-10). The most common TOAST subtypes were small-vessel disease (32.6%) and undetermined etiology (24.6%). IPSS risk factors were identified in 95% of all patients and 90% with undetermined etiology. IPSS risk factors included atherosclerosis (59.5%), cardiac disorders (18.7%), prothrombotic states (12.4%) and arteriopathy (7.7%). In this cohort, 20.3% had ESUS, of which 73.2% had at least one PES, which increased to 84.2% in those <40 years old.

CONCLUSIONS

Young adults have diverse risk factors and causes of AIS. IPSS risk factors and ESUS-PES construct are comprehensive classification systems that may better reflect heterogeneous risk factors and etiologies in young stroke patients.

Smoking, life expectancy, and chronic disease in South Korea, Singapore, and the United States: A microsimulation model

The substantial social and economic burden attributable to smoking is well-known, with heavy smokers at higher risk of chronic disease and premature mortality than light smokers and nonsmokers. In aging societies with high rates of male smoking such as in East Asia, smoking is a leading preventable risk factor for extending lives (including work-lives) and healthy aging. However, little is known about whether smoking interventions targeted at heavy smokers relative to light smokers lead to disproportionately larger improvements in life expectancy and prevalence of chronic diseases and how the effects vary across populations. Using a microsimulation model, we examined the health effects of smoking reduction by simulating an elimination of smoking among subgroups of smokers in South Korea, Singapore, and the United States. We found that life expectancy would increase by 0.2 to 1.5 years among light smokers and 2.5 to 3.7 years among heavy smokers. Whereas both interventions led to an increased life expectancy and decreased the prevalence of chronic diseases in all three countries, the life-extension benefits were greatest for those who would otherwise have been heavy smokers. Our findings illustrate how smoking interventions may have significant economic and social benefits, especially for life extension, that vary across countries.

Safety of antithrombotic therapy in East Asian patients

Antithrombotic agents are widely used on the globe for prevention of thrombotic events such as atherothrombotic events and thromboembolic stroke in atrial fibrillation or for prevention and treatment of venous thromboembolism. However, the net clinical benefit of antithrombotic intervention may differ substantially in various sub-population of patients. Here, the authors attempt to address the risk of serious bleeding in East Asian as compared to the other regions of the world. The community-based epidemiological data suggest numerically higher risk of hemorrhage stroke in East Asian as compared to the globe. Importantly, the life-time risk of ischemic stroke in East Asia is higher than that of the globe. Regarding the serious bleeding risk in East Asians with the use of antithrombotic agents, various clinical trials and international registries provided conflicting information. It is hard to draw generalized conclusion, but there are some specific sub-population in East Asian with higher risk of specific serious bleeding events with the use of specific antithrombotic agents such as the risk of intra-cranial bleeding (ICH) with Vitamin K antagonists. Specific characteristics in East Asian such as higher prevalence of lacunar stroke may contribute higher risk of ICH in East Asian, but the detailed mechanism is still to be elucidated. In conclusion, further investigations are necessary to clarify the specific conditions where the risk of serious bleeding events in East Asian patients differ substantially compared to the global. In addition, further understanding of the mechanisms causing the different bleeding response in specific conditions in East Asian is awaited.

Determinants and Outcomes of Asymptomatic Intracranial Atherosclerotic Stenosis

BACKGROUND

Intracranial atherosclerotic stenosis (ICAS) is one of the most common causes of stroke worldwide and confers a high risk of stroke recurrence, despite aggressive management of risk factors.

OBJECTIVES

This study identified the role of risk factors and risk of vascular events in subjects with asymptomatic ICAS for improved risk stratification.

METHODS

Stroke-free participants in the NOMAS (Northern Manhattan Study) trial, prospectively followed since 1993, underwent a brain magnetic resonance angiogram from 2003 to 2008. The study rated stenosis in 11 brain arteries as: 0: no stenosis; 1: <50% or luminal irregularities; 2: 50%-69%; and 3: ≥70% stenosis or flow gap. The study ascertained vascular events during the post-magnetic resonance imaging (MRI) period. Proportional odds regression quantified the association of pre-MRI exposures, and proportional hazard adjusted models were built to identify the risk of events in the post-MRI period.

RESULTS

The included sample included 1,211 participants from NOMAS (mean age: 71 ± 9 years; 59% women; 65% Hispanic; 45% had any stenosis). Older age (OR: 1.02 per year; 95% CI: 1.01 to 1.04), hypertension duration (OR: 1.01 per year; 95% CI: 1.00 to 1.02), higher number of glucose-lowering drugs (OR: 1.64 per each medication; 95% CI: 1.24 to 2.15), and high-density lipoprotein (OR: 0.96 per mg/dL; 95% CI: 0.92 to 0.99) were associated with ICAS. The highest event risk was noted among participants with ICAS ≥70% (5.5% annual risk of vascular events; HR: 2.1; 95% CI:1.4 to 3.2; compared with those with no ICAS).

CONCLUSIONS

ICAS is an imaging marker of established atherosclerotic disease in stroke-free subjects, and incidental diagnosis of ICAS should trigger a thorough assessment of vascular health.

A Scoping Review of the Association of Social Disadvantage and Cerebrovascular Disease Confirmed by Neuroimaging and Neuropathology

Social disadvantage-a state of low-income, limited education, poor living conditions, or limited social support-mediates chronic health conditions, including cerebrovascular disease. Social disadvantage is a key component in several health impact frameworks, providing explanations for how individual-level factors interact with interpersonal and environmental factors to create health disparities. Understanding the association between social disadvantage and vascular neuropathology, brain lesions identified by neuroimaging and autopsy, could provide insight into how one's social context interacts with biological processes to produce disease. The goal of this scoping review was to evaluate the scientific literature on the relationship between social disadvantage and cerebrovascular disease, confirmed through assessment of vascular neuropathology. We reviewed 4049 titles and abstracts returned from our search and included records for full-text review that evaluated a measure of social disadvantage as an exposure variable and cerebrovascular disease, confirmed through assessment of vascular neuropathology, as an outcome measure. We extracted exposures and outcomes from 20 articles meeting the criteria after full-text review, and described the study findings and populations sampled. An improved understanding of the link between social factors and cerebrovascular disease will be an important step in moving the field closer to addressing the fundamental causes of disease and towards more equitable brain health.

A hospital-based study on ischaemic stroke characteristics, management, and outcomes in Sarawak: Where do we stand?

BACKGROUND

Located on the Borneo Island, Sarawak is the largest state of Malaysia and has a population distinctive from Peninsular Malaysia. The ischaemic stroke data in Sarawak had not been reported despite the growing number of patients annually. We aimed to investigate patient characteristics, management, and outcomes of ischaemic stroke in Sarawak and benchmark the results with national and international published data.

METHODS

We included ischaemic stroke cases admitted to Sarawak General Hospital between June 2013 and August 2018 from Malaysia National Stroke Registry. We performed descriptive analyses on patient demographics, cardiovascular risk factors, prior medications, smoking status, arrival time, thrombolysis rate, Get With The Guidelines (GWTG)-Stroke measures, and outcomes at discharge. We also numerically compared the results from Sarawak with the published data from selected national and international cohorts.

RESULTS

We analysed 1435 ischaemic stroke cases. The mean age was 60.1±13.2 years old; 64.9% were male; median baseline National Institute of Health Stroke Scale was seven points. Hypertension was the most prevalent risk factor of ischaemic stroke; 12.7% had recurrent stroke; 13.7% were active smokers. The intravenous thrombolysis rate was 18.8%. We achieved 80-90% in three GWTG-Stroke performance measures and 90-98% in four additional quality measures in our ischaemic stroke management. At discharge, 57% had modified Rankin Scale of 0-2; 6.7% died during hospitalisation. When compared with selected national and international data, patients in Sarawak were the youngest; Sarawak had more male and more first-ever stroke. Thrombolysis rate in Sarawak was higher compared with most studies in the comparison. Functional outcome at discharge in Sarawak was better than national cohort but still lagging behind when compared with the developed countries. In-hospital mortality rate in Sarawak was slightly lower than the national data but higher when compared with other countries.

CONCLUSION

Our study described characteristics, management, and outcomes of ischaemic stroke in Sarawak. We achieved high compliance with most of GTWG-Stroke performance and quality indicators. Sarawak had better outcomes than the national results on ischaemic stroke. However, there is still room for improvement when compared with other countries. Actions are needed to reduce the cardiovascular burdens for stroke prevention, enhance healthcare resources for stroke care, and improve intravenous thrombolysis treatment in Sarawak.

The Long-Term Impact of Functional Disability on Hospitalization Spending in Singapore

Singapore is one of the fastest-aging populations due to increased life expectancy and lowered fertility. Lifestyle changes increase the burden of chronic diseases and disability. These have important implications for social protection systems. The goal of this paper is to model future functional disability and healthcare expenditures based on current trends. To project the health, disability and hospitalization spending of future elders, we adapted the Future Elderly Model (FEM) to Singapore. The FEM is a dynamic Markov microsimulation model developed in the US. Our main source of population data was the Singapore Chinese Health Study (SCHS) consisting of 63,000 respondents followed up over three waves from 1993 to 2010. The FEM model enables us to investigate the effects of disability compounded over the lifecycle and hospitalization spending, while adjusting for competing risk of multi-comorbidities. Results indicate that by 2050, 1 in 6 elders in Singapore will have at least one ADL disability and 1 in 3 elders will have at least one IADL disability, an increase from 1 in 12 elders and 1 in 5 elders respectively in 2014. The highest prevalence of functional disability will be in those aged 85 years and above. Lifetime hospitalization spending of elders aged 55 and above is US$24,400 (30.2%) higher among people with functional disability compared to those without disability. Policies that successfully tackle diabetes and promote healthy living may reduce or delay the onset of disability, leading to potential saving. In addition, further technological improvements may reduce the financial burden of disability.

Predictors of functional outcome in patients with stroke thrombolysis in a tertiary hospital in Malaysia

INTRODUCTION

Intravenous (IV) thrombolysis with alteplase (rt-PA) is effective in ischaemic stroke. The primary objective was to evaluate predictors of functional outcome in acute ischaemic stroke (AIS) patients treated with IV rt-PA. The secondary objective was to assess the outcome with the modified Rankin scale (mRS). We also examined the predictive value of the Totaled Health Risks in Vascular Events (THRIVE) score.

METHODS

AIS patients treated with IV rt-PA from February 2012 to August 2016 were recruited. Demographic data, National Institutes of Health Stroke Scale (NIHSS) scores, timing and neuroradiological findings were recorded. Patients received a dose of 0.9 mg/kg IV rt-PA within 4.5 hours of symptom onset. mRS score was evaluated at discharge and three months, and good and poor clinical outcomes were defined as scores of 0-2 and 3-6, respectively. Baseline THRIVE scores were assessed.

RESULTS

36 patients received IV rt-PA. 20 (55.6%) patients had an mRS score of 0-2 at three months. Based on THRIVE score, 86.1% had a good or moderately good prognosis. On univariate analysis, poor outcome was associated with NIHSS score before rt-PA (p = 0.03), THRIVE score (p = 0.02), stroke subtype (p = 0.049) and diabetes mellitus (DM; p = 0.06). Multiple logistic regression showed that outcome was significantly associated with NIHSS score before rt-PA (p = 0.032) and DM (p = 0.010).

CONCLUSION

Our newly developed Malaysian IV rt-PA service is safe, with similar outcomes to the published literature. Functional outcome after thrombolysis was associated with baseline NIHSS score and DM.

Comparative analysis of recurrent events after presentation with an index myocardial infarction or ischaemic stroke

Aims

Acute myocardial infarction (AMI) and stroke are important causes of mortality and morbidity. Our aims are to determine the comparative epidemiology of AMI and ischaemic stroke; and examine the differences in cardiovascular outcomes or mortality occurring after an AMI or stroke.

Methods and results

The Singapore National Registry of Diseases Office collects countrywide data on AMI, stroke, and mortality. Index events of AMI and ischaemic stroke between 2007 and 2012 were identified. Patients were then matched for occurrences of subsequent AMI, stroke, or death within 1-year of the index event. There were 33 222 patients with first-ever AMI and 20 982 with first-ever stroke. AMI patients were significantly more likely to be men (66.3% vs. 56.9%), non-Chinese (32.1% vs. 24.1%), and smokers (43.1% vs. 38.6%), but less likely to have hypertension (65.6% vs. 79%) and hyperlipidaemia (61.1% vs. 65.5%), compared with stroke patients. In total 6.8% of the AMI patients had recurrent AMI, whereas 4.8% of the stroke patients had recurrent stroke within 1 year; 31.7% of the AMI patients died, whereas 17.1% of the ischaemic stroke patients died within 1 year. Older age, Malay ethnicity, and diabetes mellitus were statistically significant risk factors for all-cause mortality and for the composite endpoint of AMI, stroke, and all-cause mortality, at 1 year.

Conclusions

Risk profiles of patients with AMI and stroke are significantly different. Patients suffer recurrent events in vascular territories similar to the index event. Age and diabetes mellitus are significant predictors of recurrent vascular events and mortality.

Etiologic classification of ischemic stroke: Where do we stand?

Despite major technological advances in ischemic stroke diagnostic techniques, our current understanding of stroke mechanisms and etiology continues to remain unclear in a significant percent of patients. As a result, several etiological ischemic stroke classifications have emerged during the last two decades but their reliability and validity is far from perfect and further world-wide research is needed in order to achieve the so much needed "standard reference language". An ideal ischemic stroke classification should both comprise all underlying pathologies that could potentially concur to an index event and emphasize the most likely etiological and pathophysiological mechanism. Currently available approaches to ischemic stroke classification are either phenotypic or causative in nature, a multitude of criteria being published by different authors. Phenotypic classifications are targeted towards describing the concurring underlying pathologies, without highlighting the most probable ischemic stroke etiology, while causative classifications focus on establishing the most likely cause, neglecting other associated diseases. A judicious use of this two different concepts might improve clinical research as well as daily clinical practice.

Derivation and Validation of a Scoring System for Intravenous Tissue Plasminogen Activator Use in Asian Patients

BACKGROUND AND PURPOSE

As Chinese Asian populations have an increased risk of intracerebral hemorrhage (ICH) after intravenous tissue plasminogen activator (IV tPA), we aimed to design a rapid, clinically applicable risk scoring system to predict ICH and functional outcomes after IV tPA treatment in Asian ischemic stroke patients.

METHODS

From January 2009 to December 2012, consecutive acute ischemic stroke patients treated with IV tPA recruited from the Stroke Registry in Chang Gung Healthcare System (SRICHS) in Taiwan and the National University Hospital of Singapore (NUHS) acute stroke database were used to create and validate a scoring system. Nomogram was created for ICH and 3-month mortality.

RESULTS

In total, 932 patients were included in the study: 386 from SRICHS for the derivation of scoring system and 546 from NUHS to validate it. We used nomograms to assign weightage to the scoring system. The presence of atrial fibrillation, glucose level, and the National Institutes of Health Stroke Scale (NIHSS) score were significantly associated with the risk of ICH. Age, NIHSS score, hyperlipidemia, and the presence of post-tPA ICH were significantly associated with mortality. The areas under the curve of derivation and validation cohorts were .663 and .662 for ICH, and .808 and .790 for mortality, respectively.

CONCLUSIONS

The scoring system using nomograms can provide a fast, practical, and user-friendly tool that allows physicians to predict the risk of ICH and functional outcomes with IV tPA treatment in a clinical setting.

Validation of the Stroke and Aphasia Quality of Life Scale in a multicultural population

PURPOSE

This study aimed to determine the reliability and validity of the Stroke and Aphasia Quality of Life Scale (SAQOL-39 g) and its Mandarin adaptation SAQOL-CSg in Singaporean stroke patients.

METHOD

First-time stroke survivors were recruited at three months post-stroke and underwent a series of questionnaires in their dominant language (English/Mandarin). This included: SAQOL-39 g/CSg, National University Hospital System (NUHS) Aphasia Screening Test, Barthel Index, Modified Rankin Scale, Mini Mental State Examination, Frontal Assessment Battery, Center for Epidemiologic Studies Depression Scale and the Eurol-Qol Health Questionnaire (EQ-5D). The SAQOL-39 g/SAQOL-CSg was repeated within 1 week (± 6 days).

RESULTS

Ninety-four participants (96.9%) were able to self-report and their results presented here. Both the SAQOL-39 g/SAQOL-CSg showed good internal consistency (α = 0.96/0.97), test-retest reliability (ICC= 0.99/0.98), convergent (rs  =0.64-0.81 and 0.66-0.88, respectively) and discriminant (rs = 0.35-0.53 and 0.48-0.62, respectively) validity. The correlation between the SAQOL-39 g and the EQ-5D Visual Analogue Scale was 0.27. Further inspection of the EQ-5DVAS scores revealed correlations in different directions for Malay versus Chinese participants.

CONCLUSIONS

Both the SAQOL-39 g and SAQOL-CSg demonstrated good reliability and validity. Our results suggested some influence of ethnicity in self-rating of health status in relation to SAQOL-39 g scores. Further research is warranted to examine its use with stroke survivors with greater stroke severity and over time. Implications for Rehabilitation Validation of SAQOL in Singapore: Both the SAQOL-39g and the SAQOL-CSg may be used to measure the HRQoL of stroke survivors with and without aphasia in Singapore. Further investigation is required to examine use with stroke survivors with greater stroke severity and over time.

Increased risk of stroke among patients with Crohn's disease: a population-based matched cohort study

BACKGROUND

Crohn's disease (CD) is one type of inflammatory bowel disease (IBD) that has been speculated to share prognostic factors with the development of stroke. There is controversial information in the literature regarding the association between CD and stroke. The present cohort study estimated the risk of subsequent stroke among CD patients compared with matched comparison subjects drawn from a population-based dataset in Taiwan.

METHOD

This study drew data from the Taiwan National Health Insurance Database to conduct a historical cohort study. The study cohort comprised 3309 CD patients, and the comparison cohort comprised 13,236 subjects without an IBD. Cox proportional hazards regressions were performed to estimate the risk of subsequent stroke during the follow-up period. We also conducted additional analyses stratifying by age group and gender.

RESULTS

After adjusting for selected medical co-morbidities and recent prescriptions of selected pharmaceuticals, the hazard ratio (HR) for subsequent stroke among patients with CD was found to be 1.911 (95% confidence interval (CI) = 1.65-2.22) that of comparison subjects. While we did not detect an association between stroke and CD among patients aged 30-40 years, we did detect increased risks for stroke among CD patients aged 40-50 years (HR = 2.29) and those aged over 50 years (HR = 1.88). We also found women (HR = 2.39) to be at a greater risk than men (HR = 1.50).

CONCLUSION

This study reports an increased HR for subsequent stroke among CD patients when compared to matched comparison patients without IBD in an Asian population.

Etiology and Risk Factors of Posterior Circulation Infarction Compared with Anterior Circulation Infarction

BACKGROUND

Many clinicians regard posterior circulation infarction (PCI) as different from anterior circulation infarction (ACI), leading them to apply different treatments. Few studies have validated this practice by directly comparing the etiology and risk factors of PCI and ACI.

METHODS

We compared the etiology and risk factors of 2245 consecutive patients with a diagnosis of PCI or ACI confirmed by magnetic resonance imaging in the Chengdu Stroke Registry. Stroke etiology in each patient was classified according to Trial of Org 10172 in Acute Stroke Treatment (TOAST) criteria.

RESULTS

Our sample included 482 patients (21.5%) with PCI and 1763 (78.5%) with ACI. The most frequent etiology for both infarction types was small-artery occlusion, occurring in 37.6% of patients with PCI and 37.1% of those with ACI. Cardioembolism caused infarction in a significantly smaller proportion of patients with PCI (5.4%) than in patients with ACI (13.3%; odds ratio [OR] = .373; 95% confidence interval [CI], .245-.566). Frequencies of other stroke etiologies were similar between the 2 patient groups. Analysis of risk factor frequencies in the 2 groups showed hypertension to be the most common, occurring in 47.9% of patients in either group. Multivariable analysis identified 2 factors as conferring greater risk of PCI than ACI: male gender (OR = 1.392; 95% CI, 1.085-1.786) and diabetes mellitus (OR = 1.667; 95% CI, 1.275-2.180). The same analysis identified 2 factors as conferring greater risk of ACI: atrial fibrillation (OR = .530; 95% CI, .295-.951) and heart valve disease (OR = .433; 95% CI, .203-.922). Frequencies of other possible risk factors were similar between the 2 groups.

CONCLUSIONS

These findings suggest that PCI and ACI are more similar than different in their etiology and risk factors and that the 2 types of infarction should be treated based more on etiology and risk factors than on their posterior or anterior localization.

Countrywide Stroke Incidence, Subtypes, Management and Outcome in a Multiethnic Asian Population: The Singapore Stroke Registry — Methodology

Rationale

Because of its rapidly-growing and aging populations, the global burden of stroke will be felt most strongly in Asia. Data from Asia are scarce. Even rarer are data from multiethnic populations.

Aim

The Singapore Stroke Registry is a countrywide registry of risk factors, stroke subtypes, management and outcome of incident and recurrent stroke in multiethnic Singapore.

Methods and design

Using a cold-pursuit design, potential subjects are identified from medical claims, hospital discharge summaries and death certificates. Standardized methods are used for case ascertainment and data recording by trained staff into standardized case report forms. All ages and both genders are included.

Study outcome

Stroke incidence, subtypes and mortality will be calculated. Trend data will be obtained. Inter-ethnic differences will be explored.

Discussion

The Registry has many features of an ‘ideal’ incidence study. Previously unavailable countrywide data on an Asian population will be acquired. The unique data on inter-ethnic differences will help fill knowledge gaps in stroke epidemiology.

Ischemic stroke subtype classification: an asian viewpoint

Proper classification of the causative mechanism of stroke is important for optimizing stroke treatment and assessing prognosis. The primary etiology of stroke differs according to race and ethnicity: emboli originating from the heart or extracranial large arteries are common in Western populations, whereas small-vessel occlusion or intracranial atherosclerosis is more prevalent in Asians. Intracranial atherosclerosis frequently leads to stroke by branch-artery occlusion, and the degree of stenosis in these cases is often <50%. Mild intracranial atherosclerotic stenosis may cause distal embolization, if the atherosclerotic plaque is sufficiently vulnerable. Moreover, high-resolution magnetic resonance imaging studies have identified small plaques causing infarction, even in patients with normal-appearing vascular findings. Such cases, which are prevalent in Asia, could not be classified as large-artery atherosclerosis by previous classification systems. Additionally, single subcortical infarctions, which are usually attributed to lipohyalinotic small-vessel disease, can have other causes, including microatheroma of perforators and atherothrombotic lesions at the parental artery. Single subcortical infarctions associated with parental artery disease or those bordering on the main vessel more often have atherosclerotic characteristics than do those associated with lipohyalinosis of the penetrating artery. In countries where intracranial atherosclerosis is common, such atherosclerotic single subcortical infarctions are predicted to be prevalent. These cases, however, could not be appropriately classified in previous systems. Further effort should be devoted to formulate ischemic stroke classification systems that adequately incorporate results of recent studies and reflect the underling pathologic mechanisms, especially in patients with single subcortical infarction and intracranial atherosclerosis.

Racial and ethnic disparities in stroke subtypes: a multiethnic sample of patients with stroke

Stroke subtypes have been reported to differ by race and ethnic subgroups and have not been adequately explained. We aim to evaluate if the prevalence of vascular risk factors accounts for differences observed in stroke subtypes by race/ethnicity. Patients with acute stroke were prospectively enrolled in the Miami Stroke Registry. Patients' demographic, clinical and radiological characteristics were systematically collected. Stroke subtypes were ascertained using TOAST criteria. The sample was divided into Non-Hispanic Whites (NHW), Hispanics, African Americans (AA), and Non-Hispanic Black Caribbean (NHBC). Univariable and multivariable logistic regression analyses were performed to assess differences among groups. Among 473 stroke patients (mean age 64 ± 14 years; 63.7% were men) of which 52.9% were Hispanic, 22.6% were AA, 13.5% NHBC and 11.0% were NHW. Large artery atherosclerosis was more prevalent in NHBC (OR 1.74, 95% CI 1.02-2.97) than in the other groups. Adjusting for covariates rendered the association not significant (OR 1.71, 95% CI 0.93-3.16). Cardioembolism was more frequent in Hispanics (OR 1.94, 95% CI 1.28-2.96) and NHW (OR 2.66, 95% CI 1.42-4.96) as compared to NHBC and AA combined. Adjusting for covariates, the association was no longer significant for Hispanics but was further strengthened for NHW (OR 3.02, 95% CI 1.42-6.42). Our results suggest that the vascular risk factors prevalence among different racial and ethnic groups partially explains disparities found in the prevalence of some stroke subtypes. Addressing health disparities remains an important public health aspect of stroke prevention.

5-year survival and rehospitalization due to stroke recurrence among patients with hemorrhagic or ischemic strokes in Singapore

Background

Stroke is the 4th leading cause of death and 1st leading cause of disability in Singapore. However the information on long-term post stroke outcomes for Singaporean patients was limited. This study aimed to investigate the post stroke outcomes of 5-year survival and rehospitalization due to stroke recurrence for hemorrhagic and ischemic stroke patients in Singapore. The outcomes were stratified by age, ethnic group, gender and stroke types. The causes of death and stroke recurrence were also explored in the study.

Methods

A multi-site retrospective cohort study. Patients admitted for stroke at any of the three hospitals in the National Healthcare Group of Singapore were included in the study. All study patients were followed up to 5 years. Kaplan-Meier was applied to study the time to first event, death or rehospitalization due to stroke recurrence. Cox proportional hazard model was applied to study the time to death with adjustment for stroke type, age, sex, ethnic group, and admission year. Cumulative incidence model with competing risk was applied for comparing the risks of rehospitalization due to stroke recurrence with death as the competing risk.

Results

Totally 12,559 stroke patients were included in the study. Among them, 59.3% survived for 5 years; 18.4% were rehospitalized due to stroke recurrence in 5 years. The risk of stroke recurrence and mortality increased with age in all stroke types. Gender, ethnic group and admitting year were not significantly associated with the risk of mortality or stroke recurrence in hemorrhagic stroke. Male or Malay patient had higher risk of stroke recurrence and mortality in ischemic stroke. Hemorrhagic stroke had higher early mortality while ischemic stroke had higher recurrence and late mortality. The top cause of death among died stroke patients was cerebrovascular diseases, followed by pneumonia and ischemic heart diseases. The recurrent stroke was most likely to be the same type as the initial stroke among rehospitalized stroke patients.

Conclusions

Five year post-stroke survival and rehospitalization due to stroke recurrence as well as their associations with patient demographics were studied for different stroke types in Singapore. Specific preventive strategies are needed to target the high risk groups to improve their long-term outcomes after acute stroke.

Functional Outcomes after Inpatient Rehabilitation in a Prospective Stroke Cohort

Aim:

Rehabilitation is proven to improve function following a stroke. The functional outcomes of stroke patients and benefits from rehabilitation are highly variable. We aim to describe functional outcomes and gains following inpatient rehabilitation post-stroke and identify factors associated with improved outcomes.

Methods:

In this five-years prospective study, data for 1332 consecutive stroke patients admitted to the Singapore General Hospital inpatient rehabilitation unit were charted into a custom-designed rehabilitation database. The primary outcome measure was the Functional Independence Measure (AFIM) and discharge (DFIM). The functional gain was defined as the DFIM-AFIM.

Results:

The mean age was 64.1±12.5 years, 58.9% were male patients and 78.9% consisted of ischaemic (versus haemorrhagic) strokes. The average rehabilitation length of stay (RLOS) was 18.7±13.9 days and the majority (87.7%) were discharged home. The most common risk factor was hypertension (78.4%) and urinary tract infection (21.2%) was the commonest post-stroke complication. The mean AFIM and DFIM scores were 67.9±23.0 and 83.2±23.5 respectively with a mean functional gain of 15.4±12.3 FIM points. Younger, male, and haemorrhagic stroke patients had better functional outcomes. Multiple regression analysis results revealed that higher DFIM score was associated with higher admission motor and cognitive FIM scores, younger age, male gender, employment at admission, single patients, presence of a caregiver, haemorrhagic stroke, right-sided motor impairments, absence of urinary tract infection or depression, acupunction treatment, and a longer RLOS. The regression model on functional gain was associated with similar independent predictors on DFIM scores except that a higher AFIM was associated with lower functional gains.

Conclusion:

In this large cohort study, stroke patients make significant functional gains and should be offered rehabilitation to improve outcomes. A comprehensive set of multiple interacting demographic, clinical, cultural, and social factors significanctly impact on stroke functional outcomes after inpatient rehabilitation. The identification of these factors allows optimising rehabilitation for individual patients, and is important for discharge and resource planning.

Postthrombolysis Outcomes in Acute Ischemic Stroke Patients of Asian Race-Ethnicity

Background

Race-ethnic differences may influence postthrombolysis outcomes in acute ischemic stroke patients. Guidelines for thrombolytic therapy to treat Asian stroke patients are based mostly on extrapolated western data.

Aims

We undertook to examine outcomes among Asians by comparing a propensity-matched cohort of thrombolyzed patients from a tertiary center in Singapore with nonthrombolyzed Asian comparators collated from Virtual International Stroke Trials Archives (control).

Methods

We identified propensity scores-matched patients between thrombolyzed and control Asian patients lodged in the Virtual International Stroke Trials Archives by employing propensity scores method. We compared matched patients for their distributions of three-month functional (modified Rankin scores) and neurological outcomes (National Institute of Health Stroke Scale) by employing Cochran–Mantel–Haenszel test and proportional odds logistic regression analysis. We report odds ratio and 95% confidence interval for improved outcomes on day 90.

Results

Virtual International Stroke Trials Archives and National University Hospital, Singapore, contributed 517 and 133 patients of Asian race-ethnicity ( n = 650), respectively. After propensity matching, sample size reduced to 237 patients; 104 were from Virtual International Stroke Trials Archives. Age (59·7 vs. 61·5 years, P = 0·2) and mean baseline National Institute of Health Stroke Scale scores were similar ( 14 ) between thrombolyzed and control. The odds ratio for shift toward improved modified Rankin scores and National Institute of Health Stroke Scale distributions after tissue plasminogen activator therapy were 2·8 (95% confidence interval 1·8–4·5, P < 0·0001, n = 233; Cochran–Mantel–Haenszel P < 0·0001) and 2·8 (95% confidence interval 1·7–4·7, P = 0·0008, n = 201; Cochran–Mantel–Haenszel P = 0·0001).

Conclusions

Our data indicate that Asian patients derive benefit from thrombolytic therapy.