Login to Access Video or Poster Abstract: MP35-03
Sources of Funding: None

Introduction

We previously reported that due to the inherent variability of SHBG, clinical hypogonadism is over/under-diagnosed in 20% of patients. We further analyzed the data between classically hypogonadal men (G1 - total testosterone (TT) < 300) and those men who were “missed� but were hypogonadal using calculated bioavailable testosterone (cBT < 210) with the use of SHBG (G2). We analyzed the role of SHBG in the routine testing of male factor infertility by analyzing the relationship of TT and BT to common infertility parameters.

Methods

Retrospective review of 168 males seen in a fertility clinic from 2012-2014, to investigate the accuracy of TT in the biochemical diagnosis of hypogonadism using cBT as the reference value. The relationship between TT and other infertility parameters were calculated using nonparametric Spearman correlations. We compared semen parameters between G1 and G2 in men with and without azoospermia. We utilized a multivariable sub-analysis with linear regression with backward elimination of non-significant variables. The possible predictors in the model included age, TT, varicocele, FSH, and SHBG.

Results

Using Spearman correlations, SHBG independently predicted lower semen parameters by a similar magnitude as FSH for sperm concentration (r= -0.24, p = 0.0027) and motility (r= -.16, p=.0447). Semen parameters were available for 76 men who met criteria for G1 and 46 for G2. Only SHBG levels differed significantly upon initial group comparision (p=.0001). After excluding men with azoospermia, G1 had 62 and G2 had 45 men respectively. SHBG remained significant (P=.0001) and sperm motility (p = .057) and sperm concentration (p=.09) approached significance. Using a more stringent cutoff for G2 (T<156) sperm motility was significantly different in G1 and G2 (p=.014). Linear regression to predict sperm motility and concentration eliminated age, TT, and varicocele from the model – leaving just FSH and SHBG. When predicting sperm motility, SHBG was no longer statistically significant (p=.0973) when FSH (p=0.0231) was in the model. For sperm concentration, SHBG was significant (p=0.0186) when FSH (p=0.0079) was in the model.

Conclusions

Our data demonstrates the utility of SHBG in the initial hormonal evaluation of males seen in a fertility clinic. The addition of SHBG to TT serum testing facilitates more accurate diagnosis with FT and cBT, as SHBG was the only significant parameter able to distinguish between true hypogonadal and eugonadal patients. In addition, elevated SHBG levels independently predicted decreased sperm motility and sperm concentration.

Funding

None