tailieunhanh - Statistical Methods for Survival Data Analysis 3rd phần 3

Giả sử rằng t thời gian tồn tại (năm) của 2418 nam giới với các cơn đau thắt ngực trong Ví dụ có định dạng tương tự như các tập tin dữ liệu "C: " được định nghĩa trong Ví dụ và được lưu trong "C:! ". Sau đó, mã SAS sau đây có thể được sử dụng để sản xuất một bảng cuộc sống lâm sàng như Bảng | 94 NONPARAMETRIC METHODS OF ESTIMATING SURVIVAL FUNCTIONS Assume that survival time t year from each of 2418 males with angina pectoris in Example has the same format as the data file C defined in Example and is saved in C . Then the following SAS code can be used to produce a clinical life table such as Table . data w1 infile c missover input t cens run proc lifetest data w1 outsurv wa method life intervals 0 to 15 by 1 time t cens 0 run title Life table of the survival times proc print data wa run If BMDP 1L is used the respective code is input file c . variables 2. format free. variable names t cens. form unit year. time t. status cens. response 1. estimate method life. Print. end If the SPSS SURVIVAL procedure is used the respective code is data list file c free t cens. survival tables t status cens 1 for t intervals thru 15 by 1 print. RELATIVE FIVE-YEAR AND CORRECTED SURVIVAL RATES Another approach to large-scale survival data is the calculation of the relative survival rate or annual survival ratio. The relative survival rate evaluates the survival experience of patients in terms of the general population. Greenwood 1926 first suggested this approach for evaluating the efficacy of cancer treatment If the average survival time of the patients treated equals that of a RELATIVE FIVE-YEAR AND CORRECTED SURVIVAL RATES 95 random sample of persons of the same age gender occupation and so on the patients could be considered cured. Cutler et al. 1957 1959 1960a b 1967 adopted Greenwood s idea of comparing the survival experience of cancer patients with that of the general population to ascertain 1 the ratio of observed to expected survival rates and 2 whether in time the mortality rate declines to a normal level. The relative survival rate is defined as the ratio of the survival rate probability of surviving one year for a patient under study observed rate to someone in the general population of the same age