Incidence, Treatment Patterns, and Associated Clinical Conditions of Hyperprolactinemia Identified via Nationwide Claims Data in Korea: A 13-Year Population-Based Study

Background: Hyperprolactinemia is a common endocrine disorder with significant reproductive and systemic implications. This study aimed to investigate the nationwide epidemiological trends, longitudinal shifts in pharmacological treatment, and the temporal associations of concurrent conditions and long-term sequelae in Korean women with claims-based hyperprolactinemia. Methods: A nationwide, population-based retrospective cohort study was conducted using data from the Health Insurance Review & Assessment Service (HIRA) of South Korea from 2009 to 2021. Female patients aged 10–59 years with hyperprolactinemia diagnostic claims were evaluated. We analyzed annual prevalence, incidence, diagnostic procedures, and dopamine agonist prescription patterns. Associated clinical conditions were classified into two categories based on the timing of their diagnosis relative to hyperprolactinemia: concurrent or underlying conditions present at baseline, and long-term complications that developed during the follow-up period. Results: A total of 95,616 female patients were identified after applying the selection criteria. The prevalence and incidence of hyperprolactinemia peaked among women in their early thirties, with an absolute peak at age 32. A significant pharmacological paradigm shift was observed: bromocriptine was the predominant therapy during the early study period, but cabergoline prescriptions surpassed bromocriptine in 2017. Regarding clinical work-ups, only 5.3% of the entire cohort underwent a sella magnetic resonance imaging (MRI). Regarding associated clinical conditions, reproductive disorders such as infertility (28.0%) and polycystic ovary syndrome (24.8%) showed high overall prevalence but low incidence of new diagnoses during the follow-up period. Conversely, among the patients affected by bone disorders, more than 60% of the total osteoporosis and osteopenia cases were diagnosed subsequent to the initial hyperprolactinemia diagnosis. Significant post-diagnosis incidence was also observed for metabolic disorders, including dyslipidemia and diabetes mellitus. Conclusions: Hyperprolactinemia in Korean women is highly concentrated in the peak reproductive years. The shift toward cabergoline reflects evolving clinical guidelines and improved drug accessibility. Our findings highlight that while reproductive issues often present concurrently, bone loss and metabolic complications frequently emerge as post-diagnosis sequelae. Therefore, clinical management should extend beyond prolactin normalization to include proactive, multidisciplinary screening for skeletal and metabolic health.