Table 4.

Comparison of predictive abilities of the models using PSA and PSAV at the transition point (prospective analysis)

	Cox model
Variable	Base + PSA	Base + PSAV
Overall improvement, %, in
sensitivity*	9	45
specificity*	9	13
P*	0.275	0.028
Concordance index†	0.8363	0.8872
Change in concordance index from base model†	0.0025	0.0534

^*Results from the NRI analysis based on comparison between Cox proportional hazards models involving examination of total risk of prostate cancer death for each individual. PSA and PSAV were added separately to a base model that included age and date of diagnosis. All models were examined at the transition point. We did not attempt to establish a threshold for PSA or PSAV to correctly classify subjects as there were too few events.

^†The concordance index measuring the capability of each model's predictions of death from prostate cancer.