Low-molecular-weight heparin ( in comparison to unfractionated heparin ) thromboprophylaxis lowered pulmonary embolism risk ( hazard ratio , 0.51 ; 95 % CI , 0.27-0 .95 ; p = 0.034 ) while statin use in the preceding week lowered the risk of proximal leg deep vein thrombosis ( hazard ratio , 0.46 ; 95 % CI , 0.27-0 .77 ; p = 0.004 ) .