Op threat for anaemic older men

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Elderly men with even slightly abnormal red blood counts have a higher risk of dying after major surgery, according to US research.

The study, published in Jama, examined data from 310,311 men aged 65 or older.

It is the first study to show even slight anaemia or polycythemia - when the blood count is higher than normal - raises the risk of death after surgery.

For every percentage point of deviation from what is normal, the risk of death or major heart problem rose by 1.6%.

While doctors have long known that people with established anaemia and very high blood counts are at greater surgical risk, the exact thresholds at which risk increases has never been clear.

Proportion of red blood cells Anaemic: Less than 39%Normal: 39% - 54%Polycythemic: More than 54%

Wen-Chih Wu, the lead author of the team at Brown University, said he hoped the research would change that and help doctors better interpret the results of hematocrit tests, which measure the proportion of red blood cells in the blood.

But he stressed it was too early to say whether blood transfusions or iron supplements to improve the blood cell count would help.

Under pressure

Researchers thought there were two reasons for the results.

Firstly, elderly men's hearts may have a limited ability to compensate for the effects of abnormally high or low blood counts when they also have to contend with the stress of major surgery.

But secondly, abnormally high or low blood counts may be caused by another condition which may itself contribute to mortality in the days after surgery.

Kay-Tee Khaw, Professor of Clinical Gerontology at Cambridge University, welcomed the findings, but stressed therefore that treating the blood count "may not necessarily improve surgical outcomes".

Nonetheless, she said, "the authors have been able to define the ranges of haemocrit associated with outcomes after surgery and quantify very specifically the magnitude of increase in risk associated with each point increase or decrease outside this range.

"This may be important in helping surgeons and physicians identify higher risk groups in those who are having surgery who may for example, warrant more attention."

The team, based at Brown University, looked at the medical data of 310, 311 veterans aged 65 or over who underwent major non-cardiac surgery.

The operations, which included total knee replacements, prostate surgery and hernia repairs among a range of others, took place between 1997 and 2004 in 132 Veterans' Affairs Medical Centers across the US.