J-ASPECT Study group (Principal investigator: Koji Iihara, Director of National Cerebral and Cardiovascular Center Hospital) was established to visualize the acute stroke care process, and our research field has expanded to the field of neurosurgery since 2015.
J-ASPECT is an abbreviation derived from "Nationwide survey of Acute Stroke care capacity for Proper dEsignation of Comprehensive stroke CenTer in Japan."
Our group has been collecting Diagnosis Procedure Combination (DPC) data and conducting facility surveys in the fields of stroke and neurosurgery with research funding from the Ministry of Health, Labour and Welfare and Japan Agency for Medical Research and Development. The aims of our survey are to visualize the acute stroke care process, measure the quality of each care facility, and ensure the optimal placement of stroke facilities in Japan.
Between 2011 and 2022, our group built the largest stroke- and neurosurgery-related DPC database in Japan. A total of 7.96 million cases (of which approximately 1.76 million were stroke cases) were registered in collaboration with 960 facilities.

研究代表者 九州大学大学院医学研究院脳神経外科教授 飯原弘二

Princilal investigator

Director of NCVC Hospital

Koji Iihara MD,PhD

In the "5-year plan for overcoming stroke and cardiovascular disease," which was published as a collaboration with the Japanese Circulation Society and the Japan Stroke Society in 2016, our survey project was reported as one of the most important activities, and authorized training educational facilities of the Japan Stroke Society are recommended strongly to register DPC data for our survey project.


  • Discharge patient survey
    In this survey, our group collects claims data such as Diagnosis Procedure Combination (DPC) data from nationwide stroke care facilities, and we build a database for the visualization of the acute stroke care process. We conduct various stroke- and neurosurgery-related studies based on this database.
  • Stroke care facility survey
    Every 4 years, our group sends a questionnaire to stroke care facilities in order to evaluate their capability as a comprehensive stroke center (CSC). As a result of this survey, we calculate the CSC score of each facility.
  • Close The Gap – Stroke
    The aim of this project is to evaluate the quality of stroke care by calculating evidence-based process indicators of each stroke care facility and to clarify their relationships with outcomes. In this survey, we collect additional clinical data of stroke inpatients, which are not available from DPC data. With the combination of DPC data and additional data collected in this survey, we have developed quality indicators (QIs) for stroke centers. We are continuously monitoring improvements in each stroke care facility as well.



Our research projects are mainly funded by following subsidies.

  • Ministry of Health, Labour and Welfare Science Research Grants (research project on comprehensive measures against lifestyle-related diseases, such as cardiovascular disease and diabetes)
  • Japan Agency for Medical Research and Development Research Grants (practical research project on measures against lifestyle-related diseases, such as cardiovascular disease and diabetes)