ESRI Discussion Paper Series No.374 Measuring quality of medical care by 3-year survival rate in malignant neoplasms using health insurance claims in NDB

The Economic and Social Research Institute, Cabinet Office, has been studying methods of identifying prices reflecting changes in the quality of medical care to improve the accuracy of GDP statistics. This paper examines a method for estimating the survival rate, a representative indicator of the quality of medical care, using health insurance claim data (complete set) from the "National Database of Health Insurance Claims and Specific Health Checkups of Japan". In particular, we check the validity of the estimation method using data on malignant neoplasms (cancer), for which accurate measurement is in progress at National Cancer Center of Japan (NCC). We devised an algorithm that utilizes the property of the data set that it covers all patients during the period and the assumption that those who become diagnosed as getting cancer must see doctors frequently. This assumption means that a patient who has no medical examination record for a certain period can be "deemed dead". We incorporated this assumption into the algorithm to estimate changes in patient survival over time (and thus changes in the quality of medical care). We find that it offers a fairly accurate estimate for lung cancer compared with those provided by the NCC. However, there were some discrepancies in other estimates with the data by NCC, suggesting the limitation of our method.