By 90 days , oral anticoagulant therapy had been prescribed for more patients in the intervention group than in the control group ( 52 of 280 patients [ 18.6 % ] vs. 31 of 279 [ 11.1 % ] ; absolute difference , 7.5 percentage points ; 95 % CI , 1.6 to 13.3 ; P = 0.01 ) .