Obesity and Baseline Estradiol Levels Are Independent Predictors for Initiation of Anastrozole in Hypogonadal Men on Clomiphene Citrate

PURPOSE: To assess the conversion rate from clomiphene citrate (CC) monotherapy to combination CC+anastrozole (AZ) therapy in hypogonadal men and the predictors associated with the initiation of AZ. MATERIALS AND METHODS: A retrospective review of records from hypogonadal men treated with CC in a single fertility center was performed from 2013 to 2018. Patient age, body mass index (BMI), blood pressure, and reproductive hormones were obtained at baseline. Obesity was defined as BMI≥30 kg/m(2). Cox proportional hazards models were used to identify predictors of switching to combination CC+AZ therapy. RESULTS: A total of 318 men on CC were included. Median (interquartile range) age was 34 years (30–39 years) and patients were followed for a median of 9 months (4–17 months). Of these, 97 (30.5%) were started on CC+AZ therapy. These patients had higher baseline BMI and estradiol, which in multivariable regression were significant predictors for switching to CC+AZ therapy. A threshold of 18.5 pg/mL for baseline estradiol provided the highest accuracy for predicting the addition of AZ after adjusting for baseline BMI and total testosterone levels. CONCLUSIONS: In our practice, following CC monotherapy, 30% of men were initiated on CC+AZ. Obesity (BMI≥30 kg/m(2)) and baseline estradiol ≥18.5 pg/mL can predict the conversion to combination therapy with addition of AZ. This information can be used to counsel patients and also help to identify patients who can be started on combination therapy upfront.