Prolactin measurements in a real-life setting: a population-based cohort study.

PURPOSE: Hyperprolactinemia is mainly due to pituitary disorders including prolactinomas but other causes including adverse drug reactions exist. This study aimed to assess the frequency and pattern of serum prolactin measurements in a population-wide cohort in Central Region Denmark (1.32 mill inhabitants) from 2011 to 2022. METHODS: Using the Central Denmark Region’s data warehouse, we identified all individuals who had at least one prolactin measurement in the study period. RESULTS: We identified 84,145 individuals who had at least one measurement of prolactin. Among these, 17,008 (20.3%) had at least one measurement of elevated prolactin corresponding to an incidence of 107 per 100.000 person-years. Hyperprolactinemia, defined by at least two elevated prolactin concentrations, occurred in 5,810 individuals (73.9% female), with an incidence of 36.7 per 100.000 person-years. Only 12.7% of individuals with hyperprolactinemia were treated with dopamine agonists. CONCLUSION: We found a substantial number of repeated prolactin measurements, many of which did not seem to lead to clinical action. The findings support the need for guidelines for management of hyperprolactinemia to ensure proper utilization of health resources.