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Evaluation of the Recognition of Stroke in the Emergency Room (ROSIER) Scale in Chinese Patients in Hong Kong

  • Hui-lin Jiang,

    Affiliations Accident and Emergency Medicine Academic Unit, The Chinese University of Hong Kong, Hong Kong, China, Emergency Department, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China

  • Cangel Pui-yee Chan,

    Affiliation Accident and Emergency Medicine Academic Unit, The Chinese University of Hong Kong, Hong Kong, China

  • Yuk-ki Leung,

    Affiliation Accident and Emergency Medicine Academic Unit, The Chinese University of Hong Kong, Hong Kong, China

  • Yun-mei Li,

    Affiliations Accident and Emergency Medicine Academic Unit, The Chinese University of Hong Kong, Hong Kong, China, Emergency Department, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China

  • Colin A. Graham,

    Affiliation Accident and Emergency Medicine Academic Unit, The Chinese University of Hong Kong, Hong Kong, China

  • Timothy H. Rainer

    thrainer@cuhk.edu.hk

    Affiliation Accident and Emergency Medicine Academic Unit, The Chinese University of Hong Kong, Hong Kong, China

Abstract

Background and Purpose

The objective of this study was to determine the performance of the Recognition Of Stroke In the Emergency Room (ROSIER) scale in risk-stratifying Chinese patients with suspected stroke in Hong Kong.

Methods

This was a prospective cohort study in an urban academic emergency department (ED) over a 7-month period. Patients over 18 years of age with suspected stroke were recruited between June 2011 and December 2011. ROSIER scale assessment was performed in the ED triage area. Logistic regression analysis was used to estimate the impacts of diagnostic variables, including ROSIER scale, past history and ED characteristics.

Findings

715 suspected stroke patients were recruited for assessment, of whom 371 (52%) had acute cerebrovascular disease (302 ischaemic strokes, 24 transient ischaemic attacks (TIA), 45 intracerebral haemorrhages), and 344 (48%) had other illnesses i.e. stroke mimics. Common stroke mimics were spinal neuropathy, dementia, labyrinthitis and sepsis. The suggested cut-off score of>0 for the ROSIER scale for stroke diagnosis gave a sensitivity of 87% (95%CI 83–90), a specificity of 41% (95%CI 36–47), a positive predictive value of 62% (95%CI 57–66), and a negative predictive value of 75% (95%CI 68–81), and the AUC was 0.723. The overall accuracy at cut off>0 was 65% i.e. (323+141)/715.

Interpretation

The ROSIER scale was not as effective at differentiating acute stroke from stroke mimics in Chinese patients in Hong Kong as it was in the original studies, primarily due to a much lower specificity. If the ROSIER scale is to be clinically useful in Chinese suspected stroke patients, it requires further refinement.

Introduction

Stroke is a major cause of death and the principal global cause of adult disability. In China, stroke is the second commonest cause of death [1]. The number of patients who die from stroke is three times more than that from coronary heart disease [2]. The benefits of emergency medical services (EMS) activation by patients with stroke symptoms appear to occur in both the prehospital and in-hospital settings. For faster access to acute stroke management, stroke patients need to be accurately identified in the emergency department (ED), and ideally prior to ED arrival. Prehospital staff (e.g. emergency paramedics) are the first medical contact in 38–70% [3][6] of stroke patients. However, studies have demonstrated that paramedics have inadequate levels of stroke knowledge [7] and identify only 61–72% [8][10] of stroke patients. Many studies from western countries have validated the accuracy of various scoring systems to determine suspected stroke in the prehospital setting and ED, such as the the Los Angeles prehospital stroke screen (LAPSS score), Cincinnati prehospital stroke scale, Face Arm Speech Test (FAST), the Melbourne Ambulance Stroke Screen (MASS score) and Recognition Of Stroke In the Emergency Room (ROSIER) scale [11][15].

The ROSIER scale, which was developed in a UK population, has been designed to provide physicians in the emergency department with a framework which can be used to assess patients with suspected stroke, to facilitate early identification of acute stroke and appropriate referral. The ROSIER scale uses rapidly assessable elements of history and physical examination to produce a score between −2 and +6. The original study recommended that a score>0 indicates a likely stroke, and reported a sensitivity of 92–93%, a specificity of 83–86%, a positive predictive value (PPV) of 88–90%, and a negative predictive value (NPV) of 88–91%. External validation of diagnostic scores in different clinical cohorts is important. Two previous studies attempted to validate the score in Chinese patients; but one was done in the pre-hospital setting, and the second used patients both from a neurology unit and an emergency room [16][17]. The population in Hong Kong (HK) is mainly Chinese, but their lifestyle is becoming increasingly westernized. Validation of the ROSIER scale is an important step before the score can be safely used to identify Chinese patients with stroke. The aim of this study was to investigate whether the ROSIER scale was a valid tool for identifying stroke in Chinese patients with suspected stroke presenting to an ED in Hong Kong.

Methods

Study design and study setting

In this prospective cohort study, conducted from 1 June 2011 to 31 December 2011, all patients with suspected stroke or transient ischaemic attack (TIA) were included. The study was approved by the Institutional Review Board of the Chinese University of Hong Kong and written consent was obtained from all patients or the closest available relatives.

This study was conducted in the ED of the Prince of Wales Hospital (PWH), a tertiary referral centre affiliated with the Chinese University of Hong Kong. PWH is a university hospital with 1400 beds, which is located in the New Territories in Hong Kong. The ED sees more than 150 000 new ED patients per annum, serves a local population of approximately 800 000 people, and is the regional neurosciences centre for around 1.5 million people.

Inclusion and exclusion criteria

Consecutive patients ≥18 years old, presenting to the ED with symptoms or signs suggestive of stroke or TIA were included in the study. The following patients were excluded: traumatic brain injury with an external cause such as motor vehicle crashes and falls; incomplete medical records; patients that did not present first to the ED (e.g. direct admission to a ward); and in accordance with the criteria for the original ROSIER scale, patients with subarachnoid haemorrhage (SAH), subdural haematoma (SDH) and TIA without symptoms and signs during this period. The inclusion and exclusion criteria were the same as the original article [15] thus allowing meaningful comparison.

Definitions

Stroke was defined as a focal or global neurological deficit with symptoms lasting for 24 hours, or resulting in death within 24 hours, which after investigation was thought to be due to a vascular cause. TIAs were defined as clinical syndromes characterized by an acute loss of focal cerebral or monocular function with symptoms lasting less than 24 hours and thought to be caused by inadequate blood supply as a result of thrombosis or embolism.

Stroke mimics were defined as manifestations of nonvascular disease processes when a stroke-like clinical picture is produced. The presentation resembles or may even be indistinguishable from ischaemic stroke [18].

Somatization disorder causes patients to suffer from neurological symptoms, such as numbness, blindness, paralysis, or fits without a definable organic cause. It is thought that symptoms arise in response to stressful situations affecting a patient's mental health [19].

Study protocol

All patients referred to the ED with suspected stroke were examined by research staff who completed the ROSIER proforma and data collection. The research staff were fully trained, specialist stroke nurses or a consultant in emergency medicine who performed the initial clinical examination. In addition to the ROSIER assessment or where assessment was difficult, the default was to use the NIHSS score (see Appendix S1).

Data collected prospectively during this study included patient characteristics, stroke referrals, onset and admission times, assessment time, clinical symptoms and signs, risk factor profile, Glasgow Coma Score (GCS) score, National Institutes of Health Stroke Scale (NIHSS), non-invasive blood pressure, imaging findings, final diagnosis, and early outcome at discharge. All patients suspected of stroke were reviewed by the stroke team which included four stroke nurses and two specialist doctors. The final diagnoses were made after their assessment and after review of clinical symptoms and the acute neuro-imaging (computed tomography [CT] and magnetic resonance imaging [MRI]), and this was used as the reference standard for diagnosis in the study.

Statistical analysis

Data was entered into a Microsoft Access database, and statistical analyses were done using SPSS version 17 (SPSS Inc., IBM Corporation, Chicago, IL) and MedCalc®version 11.5.1 (Mariakerke, Belgium). The prevalence of symptoms and signs were calculated. Baseline clinical characteristics were compared using Chi-square tests, unpaired t tests, and the Mann-Whitney U test. To obtain the ROSIER scale cut off points for discriminating between patients with stroke and stroke mimic, we constructed receiver operating characteristic (ROC) curves and calculated the area under the ROC curve (AUC) with 95% confidence intervals (CI). A P value of <0.05 was considered statistically significant. The sensitivity, specificity, PPV, and NPV of the ROSIER scale were calculated. Our primary aim was to evaluate in Chinese patients the suggested cut off of>0 as suggested from the original ROSIER scale. Differences between stroke patients and stroke mimic patients were assessed using descriptive statistics and standard tests of significance (as indicated). Univariate logistic regression analyses were initially performed on all ROSIER variables with p<0.1 for patients with either stroke or stroke mimic. Subsequently all ROSIER variables were analysed using multivariate logistic regression.

Results

A total of 766 patients with suspected stroke and TIA were initially recruited to the study. Fifty-one patients were excluded (four patients had incomplete medical records; two cases were not assessable; 45 cases did not meet the original ROSIER scale criteria (patients with SAH, SDH and TIA were excluded). This left 715 patients for analysis. Of these, 371 (52%) had symptoms owing to a final diagnosis of probable or definite acute cerebrovascular disease, and 344 (48%) had symptoms owing to other illnesses. Of these 715 patients, 420 patients had an onset time of less than 24 hours, and 295 patients had an onset time longer than 24 hours prior to assessment; 713 patients underwent neuroimaging: 712 patients had a CT scan, and 225 patients had an MRI scan.

Table 1 shows the baseline characteristics and ROSIER scales of these patients. The stroke patients were older than stroke mimic patients [72 years (SD13) vs 69 years (SD14), P = 0.003]. Male sex (58% vs 49%, P = 0.018), past history of hypertension, (70% vs 60%, P = 0.007), history of smoking (17% vs 8%; P<0.001), and history of atrial fibrillation (AF), 16% vs 7%; P<0.001) were more frequent in stroke patients than in stroke mimics. Patients with a past history of previous stroke and somatization were less frequent in stroke patients than in stroke mimics (25% vs 32%, P = 0.049, 1% vs 5%, P<0.001; the first SBP and DBP in stroke patients were higher than in stroke mimics. Stroke patients showed significantly higher ROSIER scales compared to stroke mimics [median 2 (IQR1–3) versus 1 (IQR0–2), P<0.001].

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Table 1. Basic characteristics and Rosier score of stroke and stroke mimic patients (n = 715).

https://doi.org/10.1371/journal.pone.0109762.t001

Table 2 shows that the distribution of stroke aetiologies were ischaemic stroke in 302 (81%), haemorrhagic stroke in 45 (12%), and TIA in 24 (7%). The most common stroke mimics were spinal neuropathy, dementia, labyrinthitis and sepsis which together comprised 33% of the 334 stroke mimic cases.

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Table 2. Primary diagnosis in study participants (n = 715).

https://doi.org/10.1371/journal.pone.0109762.t002

Table 3 shows the comparison of sensitivity and specificity. In our study, at a cut off>0, the AUC was 0.723.

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Table 3. Diagnostic performance of ROSIER instruments in Chinese patients and original ROSIER scale paper [15].

https://doi.org/10.1371/journal.pone.0109762.t003

Table 4 shows that odds ratios for stroke were increased for asymmetric facial/arm and leg weakness, speech disturbance and visual field defect. In the multivariate analyses, the adjusted odds ratio for stroke was significantly decreased for LOC/syncope, and significantly increased for asymmetric arm weakness, speech disturbance and visual field defect.

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Table 4. Univariate and multivariate logistic regression analysis of the items of ROSIER scale (n = 715).

https://doi.org/10.1371/journal.pone.0109762.t004

Figure 1 shows the distribution of the ROSIER scale categories. At a cut off>0, there are 323 stroke cases, and 202 stroke mimics, and at a cut off ≤0, there are 48 stroke cases, and 141 stroke mimics. The overall accuracy at cut off>0 is (323+141)/715 = 0.65, or 65%.

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Figure 1. Proportions of stroke diagnosis among different ROSIER scale (n = 715).

https://doi.org/10.1371/journal.pone.0109762.g001

Discussion

Formalized stroke assessment tools, based upon easily collected clinical variables, may help emergency department staff in identifying hyperacute stroke more quickly and efficiently. The ROSIER scale is one of the most widely recommended scores in the UK [20][22].

Our study is the largest to date to assess the value of the ROSIER scale in a non-Western population. At the suggested cut-off of>0, the ROSIER scale demonstrated lower sensitivity (87%) and specificity (41%) for the identification of Chinese suspected stroke patients compared to the original study [15]. A study reported by Whiteley in United Kingdom (UK) also showed that the sensitivity (83%) and specificity (44%) of the ROSIER scale in their setting was not comparable to that of the original study [23]. Although the sensitivity and specificity in our paper and Whiteley's paper is similar, nevertheless there are major differences in the clinical characteristics of our two settings. Compared with the UK, patients in Hong Kong present later after symptom onset, have different clinical presentations, less atrial fibrillation and different proportions of ROSIER score categories. One Irish study of 50 patients confirmed that the ROSIER score appears to be a sensitive instrument for assisting emergency doctors in identifying stroke patients [24] but the sample size was limited.

In Hong Kong, 95% of the population is Chinese [25] and there are significant differences in the distribution of stroke subtypes between Chinese patients [26], [27] and patients of Western origin. There is a higher proportion of intracerebral haemorrhage in Chinese compared with Western populations [28][31]. Also, in our study there were less ischaemic stroke and TIA patients (91% versus 86%), and more haemorrhagic stroke patients (12% versus 8%) than in the validation phase of the original study [15]. The proportion of stroke types in Chinese also varies from 43.7% to 78.9% for cerebral infarction, and from 18.8% to 47.6% for intracerebral haemorrhage [32,–34]. These differences in subtype patterns are postulated to be due to differences in genetic, clinical, environmental and lifestyle factors [27], [35], [36].

There are also differences in the proportion of stroke mimics between the validation phase of the original study (37%) and this study (48%). Seizures (<9%) and syncope (7%) in Hong Kong are less common stroke mimics than in the UK (57%) [15]. Another UK study found that seizures and complex migraines comprised up to 33.9% of stroke mimics [37], whilst in Greece [38] the principal stroke mimics were aphasic disturbances (27.3%) and dizziness or fainting (27.3%).

Any change of the weight of odds ratio of parameters in the ROSIER scale in the study cohort could affect its diagnostic value in Chinese patients. Compared with the original ROSIER scale, three neurological signs in Hong Kong, namely facial weakness (2.57 vs 27.0), arm weakness (2.98 vs 16.6) and leg weakness (2.61 vs 13.1) all had reduced odds ratios for the diagnosis of stroke and stroke mimic. A study investigated the diagnosis value of ROSIER scale in ambulance clinicians showed only 3 items of ROSIER scale, facial weakness (OR:2.433,95%CI:1.368–4.326), arm weakness (OR: 3.593,95%CI: 1.993–6.478), and seizure activity (OR: 3.652,95%CI: 1.279–10.426), significantly predicted stroke final diagnosis [39].

Previous studies have suggested that blood pressure (BP) is a particularly important risk factor for stroke in the Chinese population [40]. The risk of stroke associated with hypertension is consistently and significantly greater in Chinese than in Caucasians [41]. In our study, stroke patients more frequently had a history of hypertension compared to stroke mimic patients. The first blood pressure on ED admission was elevated in 95 patients (64%). The mean systolic BP reached 165 mmHg in Chinese stroke patients compared with 150 mmHg in the UK [15].

However, having a previous stroke can affect the diagnostic accuracy in this study. If patients have any prior neurological deficits, the assessment of the ROSIER score becomes especially complicated. The assessment principle of the ROSIER score is according to the NIHSS Guiding Principles: items are scored only if definitely present. So patients with previous neurological deficits will have higher ROSIER scores by default. The ratio of previous stroke patients both in both the stroke (25%)and stroke mimic (32%) groups in our study are higher than those in Nor's report (18% in both groups). This larger proportion of patients with previous stroke in our study may have affected the observed diagnostic accuracy.

This study had the following strengths. The ethnicity of the patient population is fully Chinese and therefore different from most studies investigating ROSIER. The sample size is large, especially compared with the original paper.[15] The study was conducted in the triage station of the emergency department and by well trained neurology and emergency research staff. The recruitment and analysis is exactly that same as the original paper [15] therefore allowing meaningful comparison. As the ROSIER score involves clinical assessment, no confusion should result in translating from English to Chinese.

There are several limitations in this study. Firstly, this is a single-centre study and may not reflect Asia in general. Stroke prevalence varies according to geography and ethnic background in China and this may limit the generalisability of our results.

Secondly, our original research purpose was to validate the ROSIER score in the emergency room. Some features, such as the past medical history and clinical signs (such as parasthesia and incoordination) which may increase the diagnostic value of stroke were not included in this research.

Thirdly, most recruits in our study are elderly which are a very heterogeneous group wit multiple morbidities.

In conclusion, the ROSIER scale was not as effective at differentiating acute stroke from stroke mimics in Chinese patients in Hong Kong as it was in the original studies, primarily due to a much lower specificity. There is a continuing need to develop and validate appropriate tools in the ED to improve diagnostic accuracy in the detection of stroke in the Chinese population.

Supporting Information

Author Contributions

Guarantor of the paper: THR. Oversaw the entire planning, execution, and analysis of the study: THR JHL CPYC. Had the idea for the study and obtained the ethical approval and grant for the study: THR. Recruitment of participants and data collection for the study: THR JHL YKL LYM. Prepared the statistical analysis: THR JHL. Provided advice on the study methods and manuscript writing for the study: THR CAG JHL CPYC. Wrote the first draft of the paper and prepared the manuscript: THR JHL. Contributed to the final version: HLJ CPYC YKL YML GAC THR. Took responsibility for the paper as a whole: THR CAG JHL CPYC.

References

  1. 1. Bonita R, Mendis S, Truelsen T, Bogousslavsky J, Toole J, et al. (2004) The global stroke initiative. Lancet Neurol 3: 391–3.
  2. 2. Wu Z, Yao C, Zhao D, Wu G, Wang W, et al. (2001) Sino-MONICA project A collaborative study on trends and determinants in cardiovascular diseases in China, part I: morbidity and mortality monitoring. Circulation 103: 462–8.
  3. 3. Lacy CR, Suh DC, Bueno M, Kostis JB (2001) Delay in presentation and evaluation for acute stroke: Stroke Time Registry for Outcomes Knowledge and Epidemiology (S.T.R.O.K.E.). Stroke 32: 63–9.
  4. 4. Bratina P, Greenberg L, Pasteur W, Grotta JC (1995) Current emergency department management of stroke in Houston, Texas. Stroke 26: 409–14.
  5. 5. Wein TH, Staub L, Felberg R, Hickenbottom SL, Chan W, et al. (2000) Activation of emergency medical services for acute stroke in a nonurban population: the T.L.L. Temple Foundation Stroke Project. Stroke 31: 1925–28.
  6. 6. Kothari R, Jauch E, Broderick J, Brott T, Sauerbeck L, et al. (1999) Acute stroke: delays to presentation and emergency department evaluation. Ann Emerg Med 33: 3–8.
  7. 7. Crocco TJ, Kothari RU, SayreMR LiuT (1999) A nationwide prehospital stroke survey. Prehosp Emerg Care 3: 201–6.
  8. 8. Smith WS, Isaacs M, Corry MD (1998) Accuracy of paramedic identification of stroke and transient ischemic attack in the field. Prehosp Emerg Care 2: 170–5.
  9. 9. Kothari R, Barsan W, Brott T, Broderick J, Ashbrock S (1995) Frequency and accuracy of prehospital diagnosis of acute stroke. Stroke 26: 937–41.
  10. 10. Wojner AW, Morgenstern L, Alexandrov AV, Rodriguez D, et al. (2003) Paramedic and emergency department care of stroke: baseline data from a citywide performance improvement study. Am J Crit Care 12: 411–7.
  11. 11. Kidwell CS, Starkman S, Eckstein M, Weems K, Saver JL (2000) Identifying stroke in the field. Prospective validation of the Los Angeles Prehospital Stroke Screen (LAPSS). Stroke 31: 71–6.
  12. 12. Kothari RU, Pancioli A, Liu T, Brott T, Broderick J (1999) Cincinnati Prehospital Stroke Scale: reproducibility and validity. Ann Emerg Med 33: 373–8.
  13. 13. Bray JE, Martin J, Cooper G, Barger B, Bernard S, et al. (2005) Paramedic identification of stroke: community validation of the Melbourne Ambulance Stroke Screen (MASS). Cerebrovasc Dis 20: 28–33.
  14. 14. Nor AM, McAllister C, Louw SJ, Dyker AG, Davis M, et al. (2004) Agreement between ambulance paramedic and physician-recorded neurological signs with Face Arm Speech Test (FAST) in acute stroke patients. Stroke 35: 1355–9.
  15. 15. Nor AM, Davis J, Sen B, Shipsey D, Louw SJ, et al. (2005) The Recognition of Stroke in the Emergency Room (ROSIER) scale: development and validation of a stroke recognition instrument. Lancet Neurol 4: 727–34.
  16. 16. Mingfeng H, Zhixin W, Qihong G, Lianda L, Yanbin Y, et al. (2012) Validation of the use of the ROSIER scale in prehospital assessment of stroke. Ann Indian Acad Neurol 15: 191–5.
  17. 17. Chen X-h, Mao H-f, Mo J-r, Lin P-y, Tian C-w, et al. (2013) Validation of three different stroke screen scales in an emergency setting. Chin J Crit Care Med 33: 539–42.
  18. 18. Huff SJ (2002) Stroke mimics and chameleons. Emerg Med Clin N Am 20: 583–95.
  19. 19. Stone J, Carson A, Sharpe M (2005) Functional symptoms in neurology: Assessment, J Neurology, Neurosurg Psychiatry. 76 (Suppl 1): i2–12.
  20. 20. NICE(2008) Diagnosis And Initial Management Of Acute Stroke And Transient Ischaemic Attack. NICE Clinical Guideline 68 : National Institute for Health and Clinical Excellence, Ref Type: Generic.
  21. 21. SIGN (2008) Management of patients with stroke or TIA: Assessment, investigation, immediate management and secondary prevention: Scottish Intercollegiate Guidelines Network, Report No: 108.
  22. 22. Byrne B, O'Halloran P, Cardwell C (2011) Accuracy of stroke diagnosis by registered nurses using the ROSIER tool compared to doctors using neurological assessment on a stroke unit: a prospective audit. Int J Nurs Stud 48: 979–85.
  23. 23. Whiteley WN, Wardlaw JM, Dennis MS, Sandercock PA (2011) Clinical scores for the identification of stroke and transient ischaemic attack in the emergency department: a cross-sectional study. J Neurol Neurosurg Psychiatry 82: 1006–10.
  24. 24. Jackson A, Deasy C, Geary UM, Plunkett PK, Harbison J (2008) Validation of the use of the ROSIER stroke recognition instrument in an Irish emergency department. Ir J Med Sci 177: 189–92.
  25. 25. Census and Statistics Department of Hong Kong (2007) 2006 Population By-Census – Main Report, vol I . Hong Kong, Census and Statistics Department.
  26. 26. Chau PH, Woo J, Goggins WB, Tse YK, Chan KC, et al. (2011) Trends in Stroke Incidence in Hong Kong Differ by Stroke Subtype. Cerebrovasc Dis 31: 138–46.
  27. 27. Zhang LF, Yang J, Hong Z, Yuan GG, Zhou BF, et al. (2003) Collaborative Group of China Multicenter Study of Cardiovascular Epidemiology: Proportion of different subtypes of stroke in China. Stroke 34: 2091–6.
  28. 28. Islam MS, Anderson CS, Hankey GJ, Hardie K, Carter K, et al. (2008) Trends in incidence and outcome of stroke in Perth, Western Australia during 1989 to 2001: the Perth Community Stroke Study. Stroke 39: 776–782.
  29. 29. Béjot Y, Aouba A, de Peretti C, Grimaud O, Aboa-Eboulé C, et al. (2010) Time trends in hospital-referred stroke and transient ischemic attack: result of a 7-year nationwide survey in France. Cerebrovasc Dis 30: 346–354.
  30. 30. Corso G, Bottacchi E, Giardini G, De la Pierre F, Meloni T, et al. (2009) Community-based study of stroke incidence in the Valley of Aosta, Italy. Neuroepidemiology 32: 186–195.
  31. 31. Tsai CF, Thomas B, Sudlow BLM (2013) Epidemiology of stroke and its subtypes in Chinese vs white populations. Neurology 81: 264–272.
  32. 32. Jiang B, Wang WZ, Chen HL, Hong Z, Yang QD, et al. (2006) Incidence and trends of stroke and its subtypes in China: results from three large cities. Stroke 37: 63–8.
  33. 33. Zhang LF, Yang J, Hong Z, Yuan GG, Zhou BF, et al. (2003) Proportion of different subtypes of stroke in China. Stroke 34: 2091–96.
  34. 34. Liu M, Wu B, Wang WZ, Lee LM, Zhang SH, et al. (2007) Stroke in China: epidemiology, prevention, and management strategies,. Lancet Neurol 5: 456–464.
  35. 35. Jiang B, Wang WZ, Chen H, Hong Z, Yang QD, et al. (2006) Incidence and trends of stroke and its subtypes in China: results from three large cities. Stroke 37: 63–8.
  36. 36. Feigin VL, Lawes CM, Bennett DA, Anderson CS (2003) Stroke epidemiology: a review of population-based studies of incidence, prevalence, and case-fatality in the late 20th century. Lancet Neurol 2: 43–53.
  37. 37. Hand PJ, Kwan J, Lindley RI, Dennis MS, Wardlaw JM (2006) Distinguishing Between Stroke and Mimic at the Bedside The Brain Attack Study. Stroke 37: 769–75.
  38. 38. Hatzitolios A, Savopoulos C, Ntaios G, Papadidaskalou F, Dimitrakoudi E, et al. (2008) Stroke and conditions that mimic it: a protocol secures a safe early recognition. Hippokratia 12: 98–102.
  39. 39. Fothergill RT, Williams J, Edwards MJ, Russell IT, Gompertz P (2013) Does use of the recognition of stroke in the emergency room stroke assessment tool enhance stroke recognition by ambulance clinicians? Stroke 44: 3007–12.
  40. 40. Zhang XF, Attia aJ, D'Este C, Ma XY (2006) The relationship between higher blood pressure and ischaemic, haemorrhagic stroke among Chinese and Caucasians: meta-analysis. Eur J Cardiovasc Prev Rehabil 13: 429–37.
  41. 41. Roger VL, Go AS, Lloyd-James DM, Benjamin EJ, Berry JD, et al. (2012) Heart Disease and Stroke Statistics-2012 Update: A Report from the American Heart Association. Circulation 125: e2–e220.