New analysis suggests that, contrary to what is currently thought, cholesterol-lowering statins, specifically rosuvastatin, may not prevent blood clots. Rosuvastatin is available in name brand form as Crestor and is among the most widely prescribed of all statin drugs.
It’s been estimated that rosuvastatin cut in half the risk of venous thromboembolic events such as deep venous thrombosis or DVT — a blood clot in a vein deep in the body that can cause pain and swelling in a leg.
That finding was based on a 2009 randomized controlled trial involving 34 patients, called JUPITER.
Believing the study included far too few participants and to gather more evidence about the possible benefits of statins, a group of international researchers led by Kazem Rahimi from the George Centre for Healthcare Innovation at the University of Oxford in the UK, combined the results (performed a meta-analysis) of 29 suitable published and unpublished randomised controlled trials of the effects of statins involving over 100,000 participants and more than 1000 events.
The researchers compared the effects of statins to controls and combed through mostly unpublished data on clotting events.
The difference in blood clot prevention could have happened by chance alone, they recently concluded in an issue of the journal PLOS Medicine, published by the Public Library of Science.
The authors concluded: “this study provides a more detailed assessment of the potential effects of statins (or higher dose statins) on venous thromboembolic events than has previously been possible. We were unable to confirm the large proportional reduction in risk suggested by some previous studies.”
“However, a more modest but perhaps clinically worthwhile reduction in venous thromboembolic events in some or all types of patient cannot be ruled out,” the authors added.
The researchers found the events occurred in 465 patients or 0.9 per cent in the statin group compared with 521 or 1 per cent in the control group.
It’s possible that the effect of statins was underestimated in the meta-analysis because of missing data or some other bias, the journals’ editors said.
A journal commentary accompanying the study said that in 2008, the U.S. Surgeon General issued a “call to action” to increase awareness and to prevent deep vein thrombosis and pulmonary embolism, a life-threatening condition that occurs when a clot breaks off and travels to the lungs.
In an accompanying Perspective article, Frits Rosendaal from the Leiden University Medical Center in The Netherlands (uninvolved in the study) argues that even if the study cannot provide definite answers to the statin question, some tentative conclusions can be drawn.
He says: “Firstly, that for the association between statins and venous thrombosis the methodologically strongest analysis shows at most a very small effect. Secondly, if we do not wish to discard the possibility of a beneficial effect for the whole class, any such effects are limited to rosuvastatin.”