Call for transfusion studies in anaemic stroke patients
medwireNews: Researchers call for trials of blood transfusion in stroke patients who have anaemia.
Phyo Myint (University of Aberdeen, UK) and colleagues found that anaemia at the time of hospital admission for stroke predicted mortality for up to 1 year afterwards, in 8013 patients in a regional stroke registry and in 24,816 patients from 20 studies identified in a systematic review and included in a meta-analysis.
The researchers say that there are plausible biological mechanisms for anaemia impacting stroke outcomes, such as reduced oxygen in the blood exacerbating ischaemia, as well as a potential clinical contributor, if clinicians avoid using antithrombotics in patients with anaemia.
Anaemia was common in the stroke registry patients, being present in 24.5%, and was associated with increased mortality at all timepoints in men and women with ischaemic stroke.
Among men with ischaemic stroke, being in the bottom quintile of haemoglobin levels (<12.4 g/dL) rather than the middle quintile (13.8–14.6 g/dL) was associated with a 2.64-fold increased risk of in-hospital mortality and similar increases in risk at 1, 3, 6 and 12 months later. Women had smaller but still significant risk increases, ranging from 1.47- to 1.86-fold for those in the bottom (<11.7 g/dL) versus the middle (12.8–13.6 g/dL) quintiles.
There was evidence of a U-shaped association between haemoglobin levels and outcomes in men with ischaemic stroke, who had an increased risk of in-hospital and 1-month mortality if they had haemoglobin levels above the middle quintile.
For haemorrhagic stroke, men’s outcomes were unaffected by anaemia, but women with anaemia had an increased mortality risk at most timepoints.
Patients with anaemia were older than other patients, with greater stroke severity, higher prestroke disability and more comorbidities, but the association between anaemia and mortality was independent of these and other factors.
In the meta-analysis, anaemia was associated with a significant 1.97-fold increased risk of mortality after ischaemic stroke and a smaller but still significant 1.46-fold increased risk after haemorrhagic stroke. There were too few data for the team to evaluate the impact of increased haemoglobin levels.
The researchers say that, to their knowledge, no study has yet assessed the effect of blood transfusion on anaemic patients with ischaemic stroke.
“Because of the paucity of evidence, guidelines have been unable to specify hemoglobin targets or optimal management options”, they write in the Journal of the American Heart Association.
“A randomized controlled trial is required to gauge the impact of transfusions and to establish optimum hemoglobin ranges in patients with acute stroke.”
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