The prevalence of hyperprolactinemia in non-functioning pituitary macroadenomas

Objective: The prevalence of hyperprolactinemia in non-functioning pituitary macroadenomas (NFPMAs) is not well known, and hyperprolactinemia caused by a NFPMA is currently associated with diagnostic uncertainty. Thus, the aim of this study was to evaluate the prevalence of hyperprolactinemia in NFPMAs. Methods: A meta-analysis of all existing articles in PubMed was conducted. The search string was designed as "(non-functioning pituitary tumor OR non-functioning pituitary tumor OR non-functioning pituitary macroadenomas OR non-functioning pituitary macroadenomas OR non-functioning pituitary adenomas OR non-functioning pituitary adenomas) and hyperprolactinemia". References of the articles found were also reviewed. Study selection and data extraction were performed independently by two reviewers. Data were analyzed with STATA 11.0 software (StataCorp LP, USA). The fixed effects model was used to evaluate these studies. Results: The search identified 57 published studies, seven of which were accepted for the final meta-analysis. The authors found an overall estimated 40.2% prevalence of (95% CI, 36.6%-43.7%) hyperprolactinemia in NFPMAs. Conclusions: Given the high frequency of hyperprolactinemia in NFPMAs, a diagnosis of NFPMA or prolactinoma should be made more carefully.