Passive surveillance – which uses documentation from existing health records – has the advantages of lower research costs and a lower impact on the population studied, but effectiveness is limited by the comprehensiveness of the healthcare coverage in a given community and the level of detail in medical records. [Not to mention the fact that many people may not receive a formal diagnosis (ed.)]. This article discusses the US-based Rochester Epidemiology Project for passive dementia case detection in Olmsted County (Minnesota), compared with parallel active case finding by direct assessment of individuals in an epidemiological study. The advantages and disadvantages of passive case-finding are discussed, and on balance the authors conclude that the case-finding approach chosen should ideally be tailored to the purpose of the study being conducted at the time.
Knopman, DS. Petersen, RC. [and] Rocca, WA. [et al] (2011). Passive case-finding for Alzheimer’s disease and dementia in two U.S. communities. Alzheimer’s and Dementia: the Journal of the Alzheimer’s Association, 2011, Vol.7(1), pp.53-60. (Click here to view the PubMed abstract).