Purpose: High serum prolactin concentrations have been associated with adverse health outcomes in some but not all studies. This study aimed to examine the morbidity and all-cause mortality associated with hyperprolactinaemia.
Methods: A population-based matched cohort study in Tayside (Scotland, UK) from 1988 to 2014. Record-linkage technology (biochemistry, prescribing, hospital admissions, cancer registration, maternity data, mortality and demography) was used to identify patients with hyperprolactinaemia and were compared to an age-sex matched cohort of patients free of hyperprolactinaemia. The number of deaths and incident admissions with diabetes mellitus, cardiovascular disease, cancer, breast cancer, bone fractures, and infectious conditions were compared by means of survival analysis.
Results: We identified 1,204 patients with hyperprolactinaemia (exposed group) and 5,888 age and sex matched unexposed patients as a comparison cohort. The majority of patients were women (78%) with a mean age of 39 years, and the total follow-up was 70,836 person-years with a mean follow-up of 10.1 years (SD 6.9). Patients with prolactin-secreting pituitary tumours had no increased risk of diabetes, cardiovascular disease, bone fractures, all-cause cancer or breast cancer. Whilst no increased mortality was observed in patients with pituitary microadenomas (HR=1.65, 95%CI: 0.793.45), those with macroadenomas demonstrated increased death risk (HR=2.81, 95%CI: 1.425.58), although this was not correlated with the degree of serum prolactin elevation. Increased mortality risks were also observed in those with drug-induced hyperprolactinaemia, together with increased frequency of diabetes and cardiovascular disease, but again this was not directly associated with serum prolactin concentration. None of the groups demonstrated increased rates of cancer (HR=0.98, 95%CI: 0.561.71).
Conclusions: No increased morbidity was observed in patients with prolactin-secreting pituitary tumours, whilst the increased mortality associated with pituitary macroadenomas was not correlated to the degree of serum prolactin elevation. Raised serum prolactin concentrations are unlikely to be directly related to adverse health outcomes.