Prevalence and incidence of pituitary adenomas: a population based study in Malta

Epidemiological data is important to correctly quantify the extent of disease and needed health care resources. The aim of the study was to establish the prevalence and incidence of pituitary adenomas (PAs) in the same well defined population, with in-depth analysis of the various subtypes. The design involved a retrospective cross-sectional analysis of PA patients diagnosed prior to 31 July 2011 for prevalence estimates and those diagnosed between July 2000 and July 2011 for incidence estimation. A thorough search for patients with PAs was carried out in central hospital registries including outpatients departments, surgical registries, radiological department and specialty clinic databases. Prevalence rates/100,000 and Standardised incidence ratios (SIR)/100,000/year were worked out. The respective prevalence rates and SIR for PAs overall were 75.7/100,000, and 4.27/100,000/year, for Prolactinomas 35.0/100,000 and 2.05/100,000/year, for nonfunctioning PA 25.9/100,000 and 1.79/100,000/year and for GH-secreting PAs 12.5/100,000 and 0.31/100,000/year. The overall prevalence for macroadenomas was 32.8/100,000 and SIR was 1.49/100,000/year. The prevalence rate in males for PAs overall was 46.3/100,000 and SIR was 2.08/100,000/year and in females 104.8/100,000 and SIR was 6.58/100,000/year. Females had a lower proportion of macroadenomas than males (29.5 vs. 75.0%; P < 0.001) and macroadenomas tended to present at a later age compared to microadenomas (48 vs. 34.5; P < 0.001). The highest SIR was reached in the 30-39 age group at 7.42/100,000/year. Our data confirm the considerable disease burden that PAs bear on health care resources. Males and females have similar prevalence and SIR rates for macroadenomas but there is a significant increase in SIR in females of child bearing age compared to males. These observations may have important implications in terms of the economic burden and need for early intervention.