American Journal of Epidemiology Advance Access originally published online on December 7, 2006
American Journal of Epidemiology 2007 165(5):591-596; doi:10.1093/aje/kwk042
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PRACTICE OF EPIDEMIOLOGY |
Defining Cause of Death in Stroke Patients
The Brain Attack Surveillance in Corpus Christi Project
1 Stroke Program, University of Michigan Medical School, Ann Arbor, MI
2 Stroke Program, King Fahad Medical City, Riyadh, Kingdom of Saudi Arabia
3 Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, MI
4 Division of General Medicine, The University of Texas Medical School at Houston, Houston, TX
5 Division of General Medicine, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI
6 Veterans Affairs Center for Practice Management and Outcomes Research, Ann Arbor, MI
7 Institute for Social Research, University of Michigan, Ann Arbor, MI
8 Department of Health Management and Policy, University of Michigan, Ann Arbor, MI
Reprint requests to Dr. Lewis B. Morgenstern, TC 1920/0316, 1500 East Medical Center Drive, University of Michigan, Ann Arbor, MI 48109 (e-mail: LMorgens{at}umich.edu).
Received for publication May 22, 2006. Accepted for publication July 27, 2006.
Stroke mortality is an important national health statistic and represents a frequent endpoint for epidemiologic studies. Several methods have been used to determine cause of death after stroke, but their agreement and reliability are unknown. Two hundred consecutive deaths of transient ischemic attack or ischemic stroke patients were identified (January 2000–September 2001) from an ongoing population-based stroke surveillance study in Texas, The Brain Attack Surveillance in Corpus Christi Project. Two neurologists independently recorded the cause of death based on two methods: 1) determining the underlying cause of death as defined by the World Health Organization, and 2) determining whether the death was stroke related. Kappa statistics with 95% confidence intervals were calculated by comparing agreement between methods within reviewers and between reviewers within methods. Agreement between the two cause-of-death-determination methods for each neurologist was 0.41 (95% confidence interval (CI): 0.31, 0.51) and 0.47 (95% CI: 0.38, 0.58), respectively. Agreement between neurologists for the underlying-cause-of-death method was 0.46 (95% CI: 0.32, 0.60); for the stroke-related method, it was 0.63 (95% CI: 0.52, 0.75). Accurate, reliable determinations of cause of death after stroke/transient ischemic attack are not currently feasible. More research is needed to identify a reliable process for coding cause of death from stroke.
cause of death; cerebrovascular accident; mortality
Abbreviations: CI, confidence interval; DNR, do not resuscitate; ICD-10, International Statistical Classification of Diseases and Related Health Problems, Tenth Revision; TIA, transient ischemic attack