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- Forsberg, Kalle, et al.
(author)
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A Systematic Review Of Erythropoietin In Experimental Stroke
- 2009
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In: Stroke. - 0039-2499. ; 40:4
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Conference paper (peer-reviewed)abstract
- Introduction: Erythropoietin (EPO), a hematopoietic growth factor, has promise as a neuroprotectant in animal models of ischemic stroke. EPO is thought not only to protect neurons from cell death, but also is hypothesized to promote regeneration post stroke. Here we report a systematic review and meta-analysis of the published animal data characterizing the efficacy of EPO. Methods We conducted a systematic review and random effects weighted mean difference meta-analysis only including studies describing the efficacy of EPO in models of focal cerebral ischemia. Primary outcomes were infarct size and neurobehavioral score. A stratified analysis to identify the impact of elements of study quality and design was also conducted. Results Only 11 of 943 studies met our inclusion criteria. Infarct size was reported in 15 experiments using 191 animals. Neurobehavioral score was reported in 16 experiments using 287 animals. EPO improved infarct size by 30.5% (95%Cl 19.3%-41.7%) and neurobehavioral score by 37.4% (31.2– 43.7%). For infarct size, EPO was least effective in thrombotic models of ischemia, (16% versus to 44.8% and 24% in permanent and transient models of ischemia respectively, X2 =1.47 x 10–04). Using a scoring system derived from the STAIR criteria,study quality was modest with a median score of 4 out of 11 for both outcomes. Studies that randomized to treatment group reported smaller infarct sizes compared to those that did not (18.0% versus 44.8%, n=113 versus 78 animals, X2 = 3.4 x 10–05). Studies that blinded assessment of outcome also showed a smaller improvement in neurobehavioral score (31.1% versus 41.6%, n=107 versus 167, X2 = 8.9 x 10–4). Only 11.7% of the animals in the total dataset had a co-morbidity common to human stroke (hypertension) and this co-morbidity was only reported for neurobehavioral comparisons, not for infarct size. Blinded induction of ischemia was reported in 2 experiments (21.5% of animals) measuring infarct volume. Conclusions: Aggregation of the animal data for EPO in ischemic stroke indicates mean effect sizes of 30.5% and 37.4% for infarct volume and neurobehavioral score respectively. However, when the impact of common sources of bias are considered these effect sizes fall suggesting we are overestimating its potential benefit. As common human co-morbidities may reduce therapeutic efficacy, broader testing to delineate the range of circumstances in which EPO works would be beneficial before clinical trialing.
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