The risk of of a fatal blood clot after surgery, particularly for hip and knee replacements and cancer, is higher than previously thought, according to research published in the British Medical Journal.
It reports a study of 947,000 women showing that those requiring inpatient surgery were 70 times more likely to suffer a post-operative blood clot in the first six weeks, and 10 times more likely among day-case patients.
The risk was highest in the third week after an operation, and lowest after seven to 12 weeks. The risks were similar for people suffering either a blood clot on the lung (pulmonary embolism) or deep vein (deep venous thrombosis).
The study, by a team from the Oxford University, estimates that one in 140 middle-aged women undergoing inpatient surgery will suffer a blood clot within 12 weeks, rising to one in 45 after a hip or knee replacement and one in 85 after surgery for cancer.
Among day-case patients the figure is one in 815, and one in 6,200 among women not having surgery at all. The authors conclude: “These findings suggest that the risk of venous thromboembolism (blood clot) after surgery is greater and lasts for longer than previously thought.”