The additional discriminative and reclassification value of GDF-@ beyond the independent risk factors was assessed by the category-free net reclassification improvement ( @/@ NRI ( > @ ) ) and the integrated discrimination improvement ( IDI ) RESULTS : Compared to GDF-@ < @ ng/L , a GDF-@ > @ ng/L was associated with an increased hazard ratio for death or spontaneous MI , mainly driven by mortality .