Incidence rates of first-ever ischemic stroke subtypes among blacks: A population-based study

Daniel Woo, James Gebel, Rosemary Miller, Rashmi Kothari, Thomas Brott, Jane Khoury, Shelia Salisbury, Rakesh Shukla, Arthur Pancioli, Edward Jauch, Joseph Broderick

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95 Scopus citations

Abstract

Background and Purpose - The aim of this study was to determine the incidence rates of ischemic stroke subtypes among blacks. Methods - Hospitalized and autopsied cases of stroke and transient ischemic attack among the 187 000 blacks in the 5-county region of greater Cincinnati/northern Kentucky From January 1, 1993, through June 30, 1993, were identified. Incidence rates were age- and sex-adjusted to the 1990 US population. Subtype classification was performed after extensive review of all available imaging, laboratory data, clinical information, and past medical history. Case-control comparisons of risk factors were made with age- , race-, and sex-matched control subjects. Results - Annual incidence rates per 100 000 for first-ever ischemic stroke subtypes among blacks were as follows: uncertain cause, 103 (95% confidence interval [CI], 80 to 126); cardioembolic, 56 (95% CI, 40 to 73); small-vessel infarct, 52 (95% CI, 36 to 68); large vessel, 17 (95% CI, 8 to 26); and other causes, 17 (95% CI, 9 to 26). Of the patients diagnosed with an infarct of uncertain cause, 31% underwent echocardiography, 45% underwent carotid ultrasound, and 48% had neither. Compared with age-, race-, and sex- (proportionally) matched control subjects from the greater Cincinnati/northern Kentucky region, the attributable risk of hypertension for all causes of first-ever ischemic stroke is 27% (95% CI, 7 to 43); for diabetes, 21% (95% CI, 11 to 29); and for coronary artery disease, 9% (95% CI, 2 to 16). For small-vessel ischemic stroke, the attributable risk of hypertension is 68% (95% CI, 31 to 85; odds ratio [OR], 5.0), and the attributable risk of diabetes is 30% (95% CI, 10 to 45; OR, 4.4). For cardioembolic stroke, the attributable risk of diabetes is 25% (95% CI, 4 to 41; OR, 3.1). Conclusions - Stroke of uncertain cause is the most common subtype of ischemic stroke among blacks. Cardioembolic stroke and small-vessel stroke are the most important, identifiable causes of first- ever ischemic stroke among blacks. The incidence rates of cardioembolic and large-vessel stroke are likely underestimated because noninvasive testing of the carotid arteries and echocardiography were not consistently obtained in stroke patients at the 18 regional hospitals. Most small-vessel strokes in blacks can be attributed to hypertension and diabetes.

Original languageEnglish (US)
Pages (from-to)2517-2522
Number of pages6
JournalStroke
Volume30
Issue number12
DOIs
StatePublished - Dec 1999

Keywords

  • Blacks
  • Cardioembolic stroke
  • Incidence
  • Lacunar infarction
  • Risk factors
  • Stroke, ischemic

ASJC Scopus subject areas

  • Clinical Neurology
  • Cardiology and Cardiovascular Medicine
  • Advanced and Specialized Nursing

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    Woo, D., Gebel, J., Miller, R., Kothari, R., Brott, T., Khoury, J., Salisbury, S., Shukla, R., Pancioli, A., Jauch, E., & Broderick, J. (1999). Incidence rates of first-ever ischemic stroke subtypes among blacks: A population-based study. Stroke, 30(12), 2517-2522. https://doi.org/10.1161/01.STR.30.12.2517