Comparative effectiveness research in action: dalteparin vs UFH in prevention of VTE

This is CER to be sure but it provided more questions than answers for clinicians wondering about the best treatment. The findings:

There was no significant between-group difference in the rate of proximal leg deep-vein thrombosis..

BUT:

The proportion of patients with pulmonary emboli was significantly lower with dalteparin...

..fewer patients receiving dalteparin had heparin-induced thrombocytopenia (hazard ratio, 0.27; 95% CI, 0.08 to 0.98; P=0.046).

To really complicate matters the UFH group was treated with a dose (5000 U SQ bid) known to be inferior.


One of the investigators had multiple industry ties, including to the makers of dalteparin. So this trial had a design flaw, whether inadvertent or rigged, which put unfractionated heparin at a disadvantage. Two years ago I warned about the unique vulnerability of CER to design flaws of this type.