Epidemiology studies are an essential part of clinical research, often forming the foundation for studies ranked more highly in the hierarchy of evidence-based medicine. Studies of sepsis to date have been conducted on local, regional, national and international scales, with the majority conducted in the past 5 years. Longitudinal epidemiology studies convey an important additional aspect of the healthcare burden from disease, and may additionally serve to compare the effectiveness and efficiency of healthcare systems, to examine specific patient care strategies and to perform quality control analyses.