Predicting hypogonadotropic hypogonadism persistence in male macroprolactinoma

Purpose To study the baseline characteristics predicting hypogonadotropic hypogonadism (HH) persistence in men with macroprolactinoma that achieved prolactin normalization. Design Retrospective cohort study. Methods Male patients diagnosed with macroprolactinoma and HH that received cabergoline treatment with subsequent prolactin normalization were included: men that achieved eugonadism, and men that remained hypogonadal. Patient’s demographic, clinical and biochemical parameters, sellar imaging, and visual fields tests were obtained. Univariate and multivariate models were used to identify predictors of HH persistence. Results Fifty-eight male patients (age 49.2 ± 12.6 years) with a median baseline prolactin of 1154 ng/mL (IQR 478–2763 ng/mL) and adenoma (maximal) diameter of 25.9 ± 14.8 mm were followed for a median of 5.6 years (IQR 3.0–10.7). Twelve men (21%) suffered from HH persistence at the end of follow-up and 46 men achieved eugonadism. Forty-two out of 46 men (91%) accomplished eugonadism within the first year following prolactin normalization. In a multivariate logistic regression model, hypopituitarism (OR 10.1; 95% CI 1.10–101.94), visual field defect (OR 9.9; 95% CI 1.07–92.33), and low baseline testosterone levels (OR 0.5; 95% CI 0.29–0.93) were independent predictors of HH persistence. Conclusion In our cohort of men with macroprolactinoma that reached prolactin normalization with cabergoline treatment, 21% had HH persistence. Pituitary hormone deficiency, visual field defects, and low baseline testosterone levels were independently associated with HH persistence. 91% of men achieved eugonadism within the first year following prolactin normalization. These findings may support informed clinical decision-making regarding the initiation of testosterone replacement in men with macroprolactinomas.