Impact of hemoglobin levels and anemia on mortality in acute stroke: analysis of UK regional registry data, systematic review and meta-analysis

Raphae S. Barlas, Katie Honney, Yoon K. Loke, Stephen J. McCall, Joao H. Bettencourt-Silva, Allan B. Clark, Kristian M. Bowles, Anthony K. Metcalf, Mamas A. Mamas, John F. Potter, Phyo K. Myint

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Abstract

Background: The impact of hemoglobin levels and anemia on stroke mortality remains controversial. We aimed to systematically assess this association and quantify the evidence.

Methods and Results: We analysed data from a cohort of 8,013 stroke patients (mean (sd) 77.81±11.83 years) consecutively admitted over 11 years (January 2003–May 2015) using a UK Regional Stroke Register. The impact of hemoglobin levels and anemia on mortality was assessed by sex-specific values at different time points (7-day, 14-day, 1-month, 3-month, 6-month, 1 year), using multiple regression models controlling for confounders. Anemia was present in 24.5% of the cohort on admission and was associated with increased odds of mortality at most of the time points examined up to 1 year following stroke. The association was less consistent for males with hemorrhagic stroke. Elevated haemoglobin was also associated with increased mortality, mainly within the first month. We then conducted a systematic review using the EMBASE and Medline databases. Twenty studies met the inclusion criteria. When combined with the cohort from the current study, this gave a pooled population of 29,943 patients with stroke. The evidence base was quantified in a meta-analysis. Anemia on admission was found to be associated with an increased risk of mortality in both ischemic stroke (8 studies); OR 1.97(1.56– 2.47) and hemorrhagic stroke (4 studies); OR 1.46(1.23–1.74).

Conclusions: There is strong evidence that patients with anemia have increased mortality in stroke. Targeted interventions in this patient population may improve outcomes and therefore require further evaluation.
Original languageEnglish
Article numbere003019
JournalJournal of the American Heart Association
Volume5
Issue number8
Early online date17 Aug 2016
DOIs
Publication statusPublished - Aug 2016

Keywords

  • stroke mortality
  • anaemia
  • Mortality

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