Pheochromocytoma and paraganglioma: time and space are only part of the essence.

Abstract

To examine factors associated with the reported incidence of pheochromocytoma and paraganglioma across studies. The annual incidence of pheochromocytoma and paraganglioma was examined according to geographic altitude and year of detection. Although higher altitude and later year of detection were associated with a higher incidence of disease, these variables only accounted for a small degree of the between-study differences observed. There were large amounts of residual statistical heterogeneity after meta-regression. Other factors such as variable disease detection methods, data sources, and study quality were likely more important sources of statistical heterogeneity. Variations in the incidence of pheochromocytoma and paraganglioma between studies were only partially explained by elevation and time of detection. Other factors, such as differences in study quality and the presence of clinical heterogeneity, likely impacted estimates of incidence.