ENDOCRINE SCREENING IN 1,022 MEN WITH ERECTILE DYSFUNCTION - CLINICAL-SIGNIFICANCE AND COST-EFFECTIVE STRATEGY

Purpose: We reviewed the results of serum testosterone and prolactin d etermination in 1,022 patients referred because of erectile dysfunctio n and compared the data with history, results of physical examination, other etiological investigations and effects of endocrine therapy to refine the rules of cost-effective endocrine screening and to pinpoint actual responsibility for hormonal abnormalities. Materials and Metho ds: Testosterone and prolactin were determined by radioimmunoassay. Ev ery patient was screened for testosterone and 451 were screened far pr olactin on the basis of low sexual desire, gynecomastia or testosteron e less than 4 ng./ml. Determination was repeated in case of abnormal f irst results. Prolactin results were compared with those of a previous personal cohort of 1,340 patients with erectile dysfunction and syste matic prolactin determination. Main clinical criteria tested regarding efficiency in hormone determination were low sexual desire, small tes tes and gynecomastia. Endocrine therapy consisted of testosterone hept ylate or human chorionic gonadotropin for hypogonadism and bromocripti ne for hyperprolactinemia. Results: Testosterone was less than 3 ng./m l, in 107 patients but normal in 40% at repeat determination, The prev alence of repeatedly low testosterone increased with age (4% before ag e 50 years and 9% 50 years or older). Two pituitary tumors were discov ered after testosterone determination. Most of the other low testoster one levels seemed to result from nonorganic hypothalamic dysfunction b ecause of normal serum luteinizing hormone and prolactin and to have o nly a small role in erectile dysfunction (definite improvement in only IG of 44 [36%] after androgen therapy, normal morning or nocturnal er ections in 30% and definite vasculogenic contributions in 42%). Determ ining testosterone only in cases of low sexual desire or abnormal phys ical examination would have missed 40% of the cases with low testoster one, including 37% of those subsequently improved by androgen therapy. Prolactin exceeded 20 ng./ml. in 5 men and was normal in 2 at repeat determination. Only 1 prolactinoma was discovered. These data are lowe r than those we found during the last 2 decades (overall prolactin gre ater than 20 ng./ml. in 1.86% of 1,821 patients, prolactinomas in 7, 0 .38%). Bromocriptine was definitely effective in cases with prolactin greater than 35 ng./ml. (8 of 12 compared to only 9 of 22 cases with p rolactin between 20 and 35 ng./ml,). Testosterone was low in less than 50% of cases with prolactin greater than 35 ng./ml. Conclusions: Low prevalences and effects of low testosterone and high prolactin in erec tile dysfunction cannot justify their routine determination. However, cost-effective screening strategies recommended so far missed 40 to 50 % of cases improved with endocrine therapy and the pituitary tumors. W e now advocate that before age 50 years testosterone be determined onl y in cases of low sexual desire and abnormal physical examination but that it be measured in all men older than 50 years. Prolactin should b e determined only in cases of low sexual desire, gynecomastia and/or t estosterone less than 4 ng./ml.