Blood Count May Count After Surgery
Red Blood Cell Count Before Surgery May Affect Postsurgery Risk After Age 65
June 12, 2007 -- Having a high or low red blood cell count before major
surgery may affect postsurgery deaths in adults aged 65 and older.
That's according to a new study published in The Journal of the American
The study is based on the medical records of more than 310,000 U.S. veterans
aged 65 and older.
Between 1997 and 2004, the veterans got major surgery that didn't involve
their hearts. They had their red blood cell counts measured up to three months
before their operations.
The researchers included Wen-Chih Wu, MD, of Brown University's medical
school and Rhode Island's Providence Veterans Affairs Medical Center.
They found that veterans with abnormally high or low red blood cell counts
before surgery were more likely to die or have a heart attack in the month
The findings even applied to patients with mildly high or low red blood cell
counts before surgery. Those with extremely high or low red blood cell counts
were at greater risk.
Risk in Perspective
Before surgery, nearly 57% of the patients had normal red blood cell counts,
almost 43% had low red blood cell counts (anemia), and less than 1% had high
red blood cell counts (polycythemia).
The study shows that for every percentage point above or below the normal
red blood cell count range before surgery, patients were 1.6% more likely to
die in the 30 days after surgery.
But the study doesn't prove that abnormal red blood cell counts directly
influenced patients' postsurgery deaths or heart attacks.
The researchers noticed that anemic patients tended to be older, to have
do-not-resuscitate orders, and to have health problems including diabetes,
heart disease, and kidney disease.
Patients with polycythemia were more likely to be smokers and to have
conditions including chronic obstructive pulmonary disease (COPD), the
Wu's team considered such factors in analyzing the data. Their findings
However, Wu's team notes that abnormal red blood cell counts may be a marker
-- but not a cause -- of postsurgery risk.
Since the veterans were mainly white men, the findings may not apply to
other groups of people aged 65 and older.