There was no evidence of a differential effect of apixaban over warfarin in patients with and without valvular heart disease in reducing stroke and systemic embolism ( hazard ratio -LSB- HR -RSB- , @ ; @ % confidence interval -LSB- CI -RSB- , @-@ @ and HR , @ ; @ % , CI @-@ @ ; interaction P = @ ) , causing less major bleeding ( HR , @ ; @ % CI , @-@ @ and HR , @ ; @ % CI , @-@ @ ; interaction P = @ ) , and reducing mortality ( HR , @ ; @ % CI , @-@ @ and HR , @ ; @ % CI , @-@ @ ; interaction P = @ ) .