A longitudinal characteristic curve of chronic liver disease (LCC-LD) is derived for the first time by a new method of time series data analysis, where a hospital information system is utilized as a clinical research application of the database. It describes a typical pattern of development of disease from the beginning of chronic hepatitis to the final stage of cirrhosis. The LCC-LD is obtained by effectively using patient data with various stages of developments of liver disease and the present method is applicable to derive the LCC of other diseases. The obtained LCC-LD may be useful for a clinical decision making support such as the prospective assessment (for example, the onset time of cirrhosis) of liver disease in individual patients, an evaluation of drug effect, etc.