We've known for a while that it reduces VTE but there's never been a basis for a claim that it saves lives. According to this first ever high level study it doesn't. And these were sick patients, the type we consider high risk. Once again the “quality” movement jumped the gun.
I guess even if there isn't a mortality benefit preventing the occasional VTE means something to the patient. For now I'm with the ACP guidelines which say VTE prophylaxis for medical patients should not be knee jerk but based on the level of risk.
This is for medical patients, mind you, not surgical.