Abstract: ObjectiveTo understand prognosis of patients with chromic disease or cancer and to help physicians making scientific treatment planning for these patients.MethodsA prognostic index(PI)based on the Cox's proportional hazards regression model is constructed.With the individucal PI,patients can be classified to differenthazard groups and the expected survival curves of the individual patients can be obtained.ResultsAnalysis of the example showed that the long-term survival of patients with chronic disease or cancer can be predicted.ConclusionPI is easy to calculate and may provide valuable information to physicians in the planning of treatment for individual patients and in the stratification of patients in further clinical trails.