120 Serum PSA as a Predictor of Symptomatic Hypogonadism

Abstract

INTRODUCTION AND OBJECTIVES: We often see low levels of PSA in men with symptomatic hypogonadism. The relationship between serum PSA and testosterone levels is still controversial. According to the saturation hypothesis, a significant relationship is apparent only in the low testosterone range. We hypothesize that PSA might represent a surrogate marker for symptomatic hypogonadism. METHODS: Patients presenting to our academic mens health clinic reported hypogonadal symptoms using the Aging Males Symptoms (AMS) scale which grades each hypogonadal symptom on a 5point Likert scale. Several hormonal and biochemical parameters were measured the same day the survey was completed. In order to prevent possible bias in the analysis, we selected only subjects without a history of prostate disease and with a PSA level <4 ng/mL. RESULTS: 149 men were included for analysis with an average age of 55y 10. At baseline, mean AMS scale 47 12, mean total testosterone (TT) 4.65 1.91 ng/mL, mean free testosterone(FT) 7.45 2.70 pg/mL, mean PSA 1.15 0.78ng/mL. We tested the efficacy of PSA, TT, and FT in detecting severe hypogonadism, defined as AMS scale 50 in symptomatic subjects. Receiver operating characteristic (ROC) curve analysis for PSA showed an accuracy (area under the ROC curve) of 0.667 0.046 (p<0.01), in predicting severe hypogonadism. In particular, when a threshold of 0.8 ng/mL was chosen, sensitivity and specificity for severe hypogonadism were 72.8% and 59.0%. ROC curve analysis for TT and FT showed an accuracy of 0.51 (p1⁄40.811) and 0.480 (p1⁄40.693), respectively. We also tested the efficacy of PSA in detecting severe hypogonadism, defined as FT<8.5 pg/mL. ROC curve showed an accuracy of 0.512 (p1⁄40.816). After adjusting for age, low PSA (<0.8ng/mL) was not associated with hypogonadism related features, such as metabolic syndrome. CONCLUSIONS: Our data demonstrated that PSA levels were more accurate for the prediction of severe hypogonadism compared to testosterone levels and suggest that low PSA levels may represent a new tool in confirming severe hypogonadism.