Prevalence refers to the presence of a health-related condition (e.g., CKD) in a particular population at a specific point in time (point prevalence) or, less frequently, during a specific period (period prevalence); it may be expressed as a count (number of prevalent cases) or as the proportion of cases in the population (prevalence of the condition).

Traditional topics considered for inclusion in the surveillance system cover areas of chronic kidney disease that are widely accepted and of direct relevance to public health based upon peer-reviewed research published over time. The section on emerging topics is designed to bring to light recent advances in chronic kidney disease relevant to public health surveillance of CKD. While it currently focuses on risk factors – both modifiable and non-modifiable, it is intended in the future to include other topics that provide novel insights into the burden of kidney disease, its geographic distribution and temporal trends, advances in processes of care (both diagnostic and therapeutic), and newer insights into awareness of CKD, associated health outcomes or health system capacity. These emerging topics could eventually evolve into more established concepts warranting formal attention in a CKD surveillance system and potentially even have widespread population health management, prevention and/or policy implications.