Gonadal function in human immunodeficiency virus (HIV)-infected men assessed by isotopic dilution-liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) and chemiluminescent assay.

BACKGROUND: HIV infection is associated to premature decline of serum T1,2. However, prevalence and biochemical characterization of hypogonadism in HIV-infected men are still to be well defined1,2. AIM OF THE STUDY: We evaluated the gonadal status in young to middle aged HIV-infected men in order to characterize hypogonadism by assessing circulating total T (TT) with either Liquid Chromatography tandem Mass Spectrometry (LC-MS/MS) or chemiluminescent immunoassay. METHODS: Prospective, cross-sectional, observational study on 315 consecutive HIV-infected male patients with ongoing Highly Active Antiretroviral Therapy (HAART), attending the Metabolic Clinic of Infectious Diseases. Serum TT, gonadotropins and sex hormone-binding globulin (SHBG) were measured by chemiluminescent immunoassay. Serum TT was also assessed by the gold standard LC-MS/MS in 233 patients. Free T (FT) was calculated by using Vermeulen equation3. Hypogonadism was defined as serum TT levels below 320 ng/dL and/or free T levels below 64 pg/ml4. Statistical analysis: Categorical variables were compared using Chi-Square test, while correlations were performed using Spearman’s Rho coefficient and linear regression models. RESULTS: 315 HIV-infected patients were enrolled (mean age 45.56±5.61 years) with average duration of HIV-infection of 16.57±10.45 years. Considering serum total T levels assessed by LC-MS/MS and immunoassay, 11 patients out of 233 (4.8%) and 10 patients out of 315 (3.2%) had T deficiency, respectively. TT combined with luteinizing hormone (LH) levels was used to classify hypogonadism (Table 1). No difference was found among subgroups comparing the two methodologies used for TT measurement (p=0.914). 56 patients (17.8%) showed SHBG above the normal range (>71.4 nmol/L). Considering calculated FT, the incidence of hypogonadism raised to 6.9% using either immunoassay or LC-MS/MS, respectively (Table 1), with no difference between methodologies (p=0.895). Including compensated form oh hypogonadism, the prevalence raised to 13% for TT and to 15% for FT. Patients with low FT were older than eugonadal patients (p=0.005) and showed a significantly longer duration of HIV-infection (p<0.0001) and HAART (p=0.002), while they did not differ for body mass index (p=0.231). FT showed an inverse relation with age (-0.340, p<0.0001, R2=0.116), years of infection (-0.339, p<0.0001, R2=0.120) and years of HAART (-0.346, p