title: How to define hypogonadism? Results from a population of men consulting for sexual dysfunction.
abstract: OBJECTIVE
  The thresholds for testost erone (T) and the symptoms required for defining late onset hypogonadism (LOH) are under debate. The aims of the study are: (1) to verify the association between total and calculated free T (cfT) and sexual symptoms and (2) to identify thresholds for total and calculated free T to discriminate symptomatic from asymptomatic men.
  
  
  METHODS
  A consecutive series of 4890 men attending the outpatient clinic for sexual dysfunction was retrospectively studied. Biochemical parameters were collected. The relationships between symptoms and total or calculated free T were evaluated as LOESS curves.
  
  
  RESULTS
  Severe impairment in morning erections, low libido and ED were reported by 14.6, 2.7 and 60.2 %, respectively. Simultaneous presence of severe ED and impaired morning erections or low desire was reported by 12.7 and 1.9 %, respectively. Severely reduced desire and morning erections were complained of by 1.0 %. The simultaneous presence of the three severe sexual symptoms was reported by 0.8 %. Receiver operating characteristic (ROC) curve analysis showed that the highest accuracy for total T and cfT in detecting subjects with two symptoms was observed for reduced morning erections and desire (area under the ROC curve [AUC] = 0.670 ± 0.04 and 0.747 ± 0.04, for total T and cfT, respectively, both p < 0.0001). The addition of the third symptom, ED, further improved the accuracy (AUC = 0.681 ± 0.05 and 0.784 ± 0.04, for total T and cfT, respectively, both p < 0.0001). The assessment of the Youden index showed that the best thresholds for detecting men with androgen deficiency-related symptoms are 10.4 nmol/L for total T and ranges 225-260 pmol/L for cfT.
  
  
  CONCLUSIONS
  The simultaneous presence of reduced morning erections and desire is the cluster of symptoms that, along with total T < 10.4 nmol/L or cfT <225 pmol/L, defines LOH in a specific, evidence-based manner.
authors.affiliation: Sexual Medicine and Andrology Unit, Department of Experimental and Clinical Biomedical Sciences, University of Florence, Viale Pieraccini 6, 50139, Florence, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Rastrelli
authors.affiliation: Sexual Medicine and Andrology Unit, Department of Experimental and Clinical Biomedical Sciences, University of Florence, Viale Pieraccini 6, 50139, Florence, Italy.|Endocrinology Section, Maggiore Hospital, Largo Nigrisoli 2, 40133, Bologna, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Corona
authors.affiliation: Gastroenterology Unit, Department of Experimental and Clinical Biomedical Sciences, University of Florence, Viale Pieraccini 6, 50139, Florence, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Tarocchi
authors.affiliation: Diabetes Section Geriatric Unit, Department of Critical Care, University of Florence, Via delle Oblate 1, 50139, Florence, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Mannucci
authors.affiliation: Sexual Medicine and Andrology Unit, Department of Experimental and Clinical Biomedical Sciences, University of Florence, Viale Pieraccini 6, 50139, Florence, Italy. m.maggi@dfc.unifi.it.
authors.forename: M
authors.initials: M
authors.lastname: Maggi
mesh_terms: D007172:Erectile Dysfunction / Q000097:blood / Q000453:epidemiology / Q000209:etiology*; D005500:Follow-Up Studies; D006801:Humans; D007006:Hypogonadism / Q000097:blood / Q000150:complications* / Q000453:epidemiology; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012372:ROC Curve; D012189:Retrospective Studies; D013739:Testosterone / Q000097:blood
chemical_list: D013739:Testosterone
keywords: Definition; Erectile dysfunction; Hypogonadism; Impaired morning erections; Low libido; Sexual symptoms