Association between admission haematocrit and mortality among men with acute ischaemic stroke

Jason J. Sico, Laura J. Myers, Brenda J. Fenton, John Concato, Linda S. Williams, Dawn M. Bravata

Research output: Contribution to journalArticle

Abstract

Objective Anaemia is associated with higher mortality among patients with non-stroke cardiovascular conditions; less is known regarding the relationship between anaemia and mortality among patients with acute ischaemic stroke. Methods Medical records were abstracted for n=3965 veterans from 131 Veterans Health Administration facilities who were admitted with ischaemic stroke in fiscal year 2007. Haematocrit values within 24 hours of admission were classified as ≤27%, 28%-32%, 33%-37%, 38%-42%, 43%-47% or ≥48%. Multivariate logistic regression was used to examine the relationship between anaemia and in-hospital, 30-day, 6-month and 1-year mortality, adjusting for age, medical comorbidities, modified Acute Physiology and Chronic Health Evaluation-III and stroke severity. Impact factors were calculated to standardise comparisons between haematocrit tier and other covariates. Results Among n=3750 patients included in the analysis, the haematocrit values were ≤27% in 2.1% (n=78), 28%-32% in 6.2% (n=234), 33%-37% in 17.9% (n=670), 38%-42% in 36.4% (n=1366), 43%-47% in 28.2% (n=1059) and ≥48% in 9.1% (n=343). Patients with haematocrit ≤27%, compared with patients in the 38%-42% range, were more likely to have died across all follow-up intervals, with statistically significant adjusted ORs (aORs) ranging from 2.5 to 3.5. Patients with polycythaemia (ie, haematocrit ≥48%) were at increased risk of in-hospital mortality (aOR=2.9; 95% CI 1.4 to 6.0), compared with patients with mid-range admission haematocrits. Pronounced differences between patients receiving and not receiving blood transfusion limited our ability to perform a propensity analysis. Impact factors in the 1-year mortality model were 0.46 (severe anaemia), 0.06 (cancer) and 0.018 (heart disease). Conclusions Anaemia is independently associated with an increased risk of death throughout the first year post stroke; high haematocrit is associated with early poststroke mortality. Severe anaemia is associated with 1-year mortality to a greater degree than cancer or heart disease. These data cannot address the question of whether interventions targeting anaemia might improve patient outcomes.

Original languageEnglish (US)
Pages (from-to)160-168
Number of pages9
JournalStroke and Vascular Neurology
Volume3
Issue number3
DOIs
StatePublished - Sep 1 2018

Keywords

  • anemia
  • hematocrit
  • ischemic stroke
  • mortality
  • polycythemia

ASJC Scopus subject areas

  • Clinical Neurology
  • Cardiology and Cardiovascular Medicine

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