Study: Hip replacements in some could lead to blood clots

BOSTON, Massachusetts (AP) -- A few extra pounds (kilograms) increase the likelihood of dangerous blood clots after hip replacement surgery, a U.S. study has found.

Researchers at the University of California at Davis Medical Center looked at California Medicare records of 25,388 patients who underwent hip replacement from 1993 through 1996. They found that 297 were re-admitted to the hospital within three weeks because a bit of blood clot had broken off and blocked a vein.

Women were found to be more likely than men to develop the blockages, called embolisms. And people with a body mass index of 25 -- the low edge of the overweight range -- were more likely to develop them than people with normal body mass.

Obese people, those who are extremely overweight, did not have a greater risk than those who were moderately overweight.

The study was published in Thursday's New England Journal of Medicine.

The blood thinner warfarin helped prevent the complication. So did use of a pneumatic compression device to reduce swelling in the legs, but only for people with a body mass index less than 25.

Body mass index is calculated by dividing weight in kilograms by the square of height in meters. A peson who is 1.6 meters tall and weights 65.7 kilograms has a BMI of 25.

Body mass is found by multiplying weight in pounds by 703, then dividing that by the square of height in inches. Someone who is 5-foot-1 and weighs 132 pounds has a body mass index of 25.

Copyright 2000 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

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University of California, Davis, Medical Center

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