A new study provides additional support that inflammatory markers are associated with a poor outcome following stroke, according to a research article by William Whiteley (Western General Hospital, Edinburgh) and colleagues. The findings, published in the open-access journal PLoS Medicine this week also show that inflammatory markers were not a useful addition to existing prognostic models in predicting the outcome of stroke.

Every year, around the world,15 million people suffer a stroke when the blood supply to the brain is interrupted; either by a blockage or a bleed in the blood vessels. Many people are left with permanent disabilities because of the brain damage caused by stroke. Some previous studies have suggested that the levels of inflammatory markers in the blood could be useful in predicting outcome after stroke.

In this prospective cohort study, Whiteley and colleagues followed the progress of 844 patients who had experienced a recent stroke at the Western General Hospital, Edinburgh. The researchers measured levels of inflammatory markers (such as interleukin-6 and C-reactive protein) in the blood at the time of clinical assessment, or soon afterwards. Also, clinicians assessed 6 simple clinical variables, including ability to walk unaided and awareness of present situation, in a stroke prognostic model to predict patient outcome. Patients were followed up to 6 months after the stroke onset date. Statistical analysis of the data showed that raised levels of several inflammatory markers were associated with a poor outcome; after allowing for age and other factors, only interleukin-6 showed an independent and significant association with a poor outcome. However, addition of interleukin-6 to an existing model for stroke prognosis did not sufficiently improve prediction of outcomes in this cohort to be useful. Peter Sandercock, one of the authors of the study at the University of Edinburgh says, ""We had hoped these blood tests would help us give better advice on whether a stroke patient might recover or not. Although the results haven't fulfilled that promise, they do indicate that inflammation may be an important target to pursue in the search for new treatments for stroke."

In an accompanying Perspective also published in PLoS Medicine, Leonard Kritharides (not involved in the research) from the University of Sydney, Australia, comments that the study "reassures clinicians" that existing simple clinical prognosis models give meaningful predictions of outcome after stroke.

William Whiteley is supported by a Chief Scientist's Office Clinical Academic Training Fellowship from the Scottish Government. CS was supported by a Clinician Scientist Award from the Wellcome Trust (063668/Z/01/A) and is now funded by the Scottish Funding Council. CJ was supported by the Wellcome Trust (063668/Z/01/A) and now holds a Binks Trust Research Fellowship. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

"Inflammatory Markers and Poor Outcome after Stroke: A Prospective Cohort Study and Systematic Review of Interleukin-6."
Whiteley W, Jackson C, Lewis S, Lowe G, Rumley A, et al. (2009)
PLoS Med 6(9): e1000145. doi:10.1371/journal.pmed.1000145

PLoS Medicine

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