Inflammatory markers in the blood identify higher risk of fatal heart attacks, suggests study

Issued: Tue, 23 Jun 2009 09:18:00 BST

The presence of inflammatory markers in the blood of elderly people at risk of cardiovascular disease can identify individuals at higher risk of a fatal heart attack or stroke, a study has found.

Inflammation is an immune response to injury but is also believed to play a part in cardiovascular disease with previous studies indicating a link between high levels of markers of inflammation in the circulation with a higher risk of heart attack or stroke.

Researchers at the University of Glasgow hope the discovery will result in further investigation into how inflammatory markers might predict the risk of death from heart disease and whether treatments which reduce inflammation might reduce mortality.

The study, led by Prof Naveed Sattar in the British Heart Foundation Glasgow Cardiovascular Research Centre (BHF GCRC) and Prof David Stott, David Cargill Chair of Geriatric Medicine in the Department of Cardiovascular and Medical Sciences, analysed data from an existing trial known as PROSPER (the Prospective Study of Pravastatin in the Elderly at Risk).

The PROSPER trial involved participants aged between 70 and 82 who had or were at risk of cardiovascular disease. Three inflammatory markers were examined – interleukin-6 (IL-6), C-reactive protein (CRP) and fibrinogen – and each was shown to be more strongly associated with fatal cardiovascular events than with non-fatal cardiovascular events over a three-year period.

Prof Stott said: “Our findings suggest that underlying levels of inflammation may be an important factor in determining the severity of circulatory disease in older people. Increased inflammation appears to act as a contributor to fatal outcome, however inflammation appears to be more weakly linked with more minor or non-fatal disease.

“These findings have important implications for prevention of vascular disease in older people; reducing levels of inflammation (for example with drug treatments) might prolong life, but the population burden associated with more minor disease would not be expected to be reduced.”

Using several statistical models, the researchers found that in this group of elderly patients increased levels of all three inflammatory markers, and in particular IL-6, were more strongly associated with a fatal heart attack or stroke than with a non-fatal heart attack or stroke.

They also investigated the predictive value of these inflammatory markers – in other words, whether it was useful to include these markers in tools designed to distinguish between individuals with a high and a low risk of heart attacks, strokes and other cardiovascular events.

They report that adding IL-6 to the established risk factors in predictive tools – including lifestyle factors such as smoking, high blood pressure and high blood cholesterol, all of which greatly increase the risk of cardiovascular disease – could help better identify those individuals at a risk of a fatal stroke or heart attack, but not those at risk of a non-fatal cardiovascular event.

The researchers acknowledge that these findings now need to be confirmed in younger populations and larger studies to demonstrate an outright association and the design of the current study cannot show whether the proposed association is a causal one.

Prof Sattar said: “Our results should stimulate researchers to examine the extent to which other risk factors relate differently to fatal and non-fatal cardiac events. With such knowledge, we may be able to better target those at risk of dying from a heart attack. Our results may also help us better understand the nature of heart disease risk in conditions such as rheumatoid arthritis associated with high levels of inflammation”.

The study is published this week in the open access journal PLoS Medicine.

For more information contact Stuart Forsyth in the University of Glasgow Media Relations Office on 0141 330 4831 or email s.forsyth@admin.gla.ac.uk

Notes to Editors
The full paper can be freely read here.

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