Background and Purpose: As a model for epidemiological research based on case registration system, adult chronic subdural hematoma (CSDH) study is presented, which has been investigated with the data from the Miyagi Neurotrauma Data Bank. In this article, both advantages and disadvantages of local epidemiological research based on case registration system are discussed.
Clinical Materials and Methods: The local case registration system in this study covers all of neurosurgical facilities in Miyagi prefecture, and the patient registration has been started since 1996. Adult patients with CSDH, registered between 2005 and 2007, are subjected to this study (1,445 patients, M:F=1,021:424, mean age 71.2±12.8 y.o.), to investigate the incidence of adult CSDH.
Results: The overall incidence of adult CSDH was 20.6 ⁄ 100,000 ⁄ year, with 39.2 in the age group of 60–69 y.o., 76.5 in the age group of 70–79 y.o., and 127.1 in the age group of over 80 y.o. Compared to previous reports, this study demonstrates a marked increase in the incidence of CSDH. Not only population aging but also both increase in diagnosis accuracy and current medical trends (such as increases of the elderly patients who receive hemodialysis, anticoagulant, and/or antiplatelet therapies) may influence the increase of CSDH incidence.
Conclusion: The Miyagi Neurotrauma Data Bank is a local survey, being reliable in its data quality, quantity, and completeness. The local features of Miyagi area suggest that the results of this study reflect the trend of Japan. A local survey based on case registration system may have a potential to generalize a universal truth, although it depends on its research design and/or on local features.