Association between glomerular filtration rate, free, total, and percent free prostate-specific antigen.
OBJECTIVE
To determine the relationship between glomerular filtration rate (GFR) and free prostate-specific antigen (fPSA), percent-free PSA (%fPSA), and total PSA (tPSA) in patients with diminished kidney function not on dialysis, using nationally representative data.


METHODS
A total of 3782 men aged ≥ 40 years who participated in the National Health and Nutrition Examination Survey 2001-2006, and who met eligibility criteria for PSA testing were included in the final study population. GFR (mL/min/1.73 m(2)) was calculated using the Modification of Diet in Renal Disease equation 7 and categorized as ≥ 90, 60 to < 90, and 15 to < 60. Distribution of tPSA, fPSA, and %fPSA were estimated by GFR category and by age and race. Multivariate linear regression models were fit to determine the adjusted relationship between GFR and tPSA and %fPSA after adjusting for age, race, and body mass index.


RESULTS
The multivariate linear regression analysis showed that GFR had a linear relationship with tPSA that was of borderline significance. There was a significant nonlinear relationship between GFR and %fPSA (P < .001): increased GFR was associated with a decrease in %fPSA for GFR levels below 90 [eg, change in %fPSA = -2.67 (95% CI -3.56, -1.77) for a GFR of 85 as compared with 65; P < .001]. The decline in %fPSA with increasing GFR was nonsignificant for GFR levels above 90.


CONCLUSIONS
Our finding that renal function as measured by GFR is negatively associated with %fPSA has potential implications for use of this test in men with renal disease.
Division of Cancer Prevention and Control, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, USA. dajoseph@cdc.gov
Djenaba A
DA
Joseph
Trevor
T
Thompson
Mona
M
Saraiya
David M
DM
Werny
D000328:Adult; D000368:Aged; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000175:diagnosis; D051436:Renal Insufficiency, Chronic / Q000097:blood* / Q000503:physiopathology
D017430:Prostate-Specific Antigen