1 in 10 hospital deaths in Australia are from blood clots – new research reveals a better way of preventing them after common surgeries

19 August 2024

New research published today in the Internal Medicine Journal, a publication of the Royal Australasian College of Physicians, suggests that patients who undergo total knee and total hip replacements may not be getting the best treatment to prevent deadly blood clots following surgery.

Dr Nameer van Oosterom, lead researcher of the study, says this could impact the tens of thousands of people who undergo total hip replacements (THA, or Total Hip Arthroplasty) and total knee replacements (TKA, or Total Knee Arthroplasty) annually.

“Aspirin is the most common drug given to patients after they have total hip and knee replacements to prevent blood clots, but our research suggests this might not be the best medication for all patients,” Dr van Oosterom said.

“Our research finds that patients who undergo THA and TKA have an increased number of risk factors which may result in them being aspirin resistant, and therefore are at greater risk of getting a blood clot if they take aspirin.”

“Aspirin is the most common drug prescribed in Australian hospitals to prevent blood clots after THA and TKA, but there are other drugs available that should be considered.”

“Blood clots, also known as VTE or Venous thromboembolism, are the 7th most common hospital acquired complication in Australia and makes up 10% of all deaths in Australian hospitals, while causing significant morbidity to patients, and healthcare expenditure.

“VTE is a serious threat, and one of the greatest risk factors for people who have knee and hip replacements – improving the way we administer preventative drugs could be lifesaving.”   

The study included 1,011 patients from six Australian hospitals over a one-year period. It aimed to evaluate the relationship between risk factors for blood clots and aspirin resistance (including diabetes, high cholesterol, high blood pressure, obesity and old age) with the medications used to prevent VTE in patients who had total knee or total hip replacements.

“Our study shows a significant number of people who have knee and hip replacements also have a high number of risk factors for blood clots and aspirin resistance, suggesting aspirin may not be the best medicine in many patients to prevent blood clots.

“More than half – 58.4% – of our cohort had one or two concurrent risk factors for aspirin resistance, of which, 42.4% received aspirin, which was the most used medicine prescribed to this group to prevent blood clots after their knee or hip replacement.

“We don’t know the degree of increased risk of blood clots that aspirin resistance has for patients having a TKA and THA patients – but if there is any indication based on aspirin resistant patients who have had heart and brain conditions, it’s likely very significant.

“As medical professionals, we are constantly learning and growing our evidence-base and our job is to understand healthcare treatments that won’t work just as much as we know what care will work to ensure the best chance of positive health outcomes. We need to be prescribing medications that are individualised to our patients’ needs, comorbidities and risk factors.” Dr van Oosterom said. 

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