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Original article
Association between admission haematocrit and mortality among men with acute ischaemic stroke
  1. Jason J Sico1,2,3,4,5,
  2. Laura J Myers6,7,
  3. Brenda J Fenton5,8,
  4. John Concato3,4,9,
  5. Linda S Williams6,7,10,11,
  6. Dawn M Bravata6,7,10,11,12
  1. 1 Neurology Service, VA Connecticut Healthcare System, West Haven, Connecticut, USA
  2. 2 Department of Neurology, Center for NeuroEpidemiological and Clinical Neurological Research, Yale University School of Medicine, New Haven, Connecticut, USA
  3. 3 Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
  4. 4 Clinical Epidemiology Research Center (CERC), VA Connecticut Healthcare System, West Haven, Connecticut, USA
  5. 5 Pain Research, Informatics, Multimorbidities and Education (PRIME) Center of Innovation, VA Connecticut Healthcare System, West Haven, Connecticut, USA
  6. 6 Communication and the HSR&D Stroke Quality Enhancement Research Initiative (QUERI), Richard L Roudebush VA Medical Center, Indianapolis, Indiana, USA
  7. 7 VA Health Services Research and Development (HSR&D), Center for Healthcare Informatics, Richard L Roudebush VA Medical Center, Indianapolis, Indiana, USA
  8. 8 Division of Chronic Disease Epidemiology, Yale School of Public Health, West Haven, Connecticut, USA
  9. 9 Medical Service, VA Connecticut Healthcare System, West Haven, Connecticut, USA
  10. 10 Regenstrief Institute, Indianapolis, Indiana, USA
  11. 11 Department of Neurology, Indiana University School of Medicine, Indianapolis, Indiana, USA
  12. 12 Department of Internal Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
  1. Correspondence to Dr Jason J Sico; jason.sico{at}yale.edu

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.

  • ischemic stroke
  • anemia
  • polycythemia
  • hematocrit
  • mortality

This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/

https://doi.org/10.1136/svn-2018-000149

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    Footnotes

    • Contributors JJS: study concept and design; analysis and interpretation. LJM, BJF: analysis and interpretation. JC, LSW: study concept and design; critical revision of the manuscript for important intellectual content. DMB: study concept and design; analysis and interpretation; critical revision of the manuscript for important intellectual content.

    • Funding This work was supported by the Department of Veterans Affairs, VHA, Office of Quality and Performance, and Health Services Research & Development Service Quality Enhancement Research Initiative Service Directed Project 12-178 and Career Development Award 11-262, and the Department of Veterans Affairs, Health Services Research & Development, Stroke Quality Enhancement Research Initiative (QUERI) Rapid Response Project 09-184. The views expressed in this article are those of the authors and do not necessarily represent the view of the Department of Veterans Affairs.

    • Competing interests None declared.

    • Patient consent Not required.

    • Ethics approval The VA Institutional Review Boards in West Haven, Connecticut, and Indianapolis, Indiana, approved this study.

    • Provenance and peer review Not commissioned; internally peer reviewed.

    • Data sharing statement No additional data are available.