Serum prostate-specific antigen to predict the presence of bladder outlet obstruction in men with urinary symptoms

OBJECTIVE: To determine whether prostate specific antigen (PSA) level can usefully predict or exclude bladder outlet obstruction (BOO), in men with lower urinary tract symptoms (LUTS). PATIENTS AND METHODS: A cohort of men from 1996 to 1999 who had LUTS caused by BPH was evaluated by serum PSA and pressure-flow urodynamic studies, and a blinded comparison made. The settings were teaching hospitals in London, UK and L'Aquila, Italy. Men (302) were referred by primary-care practitioners with LUTS and a PSA of <10 ng/mL. Regression analysis was used to predict the extent of BOO, and create likelihood ratios and predictive values for BOO according to the PSA value. RESULTS: PSA was significantly associated with BOO (P < 0.001 ; r2 0.07), with significant likelihood ratios altering the probability of BOO. If the PSA was >4 ng/mL, mild or definite BOO was likely (89%), whereas if the PSA was <2 ng/ mL, there was about a one-third chance each of no, mild and definite BOO. CONCLUSION: High PSA levels in patients with LUTS are significantly associated with BOO; low PSA levels mean that definite BOO is unlikely.