The LIFETEST procedure in SAS/STAT is a nonparametric procedure for analyzing survival data. You can use PROC LIFETEST to compute the Kaplan-Meier (1958) curve, which is a nonparametric maximum likelihood estimate of the survivor function. You can display the Kaplan-Meier plot that contains step functions representing the Kaplan-Meier, The PROC LIFETEST statement invokes the procedure . Optionally, this statement identifies an input and an OUTSURV= data set, and specifies the computation details of the survivor function estimation. The options listed in Table 49.1 are available in the PROC LIFETEST statement and are described in alphabetic order.
In the following statements, PROC LIFETEST is invoked to compute the product-limit estimate of the survivor function for each type of cancer cell and to analyze the effects of the variables Age, Prior, DiagTime, Kps, and Treatment on the survival of the patients.
The PROC LIFETEST statement invokes the procedure . Optionally, this statement identifies an input and an OUTSURV= data set, and specifies the computation details of the survivor function estimation. The options listed in Table 49.1 are available in the PROC LIFETEST statement and are described in alphabetic order. If no options are requested, PROC LIFETEST computes and displays the product-limit estimate .
PROC LIFETEST is invoked as follows to compute the product-limit estimate of the survivor function for each treatment and to compare the survivor functions between the two treatments: ods graphics on proc lifetest data=Exposed plots=(survival(atrisk) logsurv) time Days*Status(0) strata Treatment run ods.
Chapter 37 The LIFETEST Procedure – Academics | | WPI, SAS/STAT( R ) 9.2 User’s Guide, Second Edition – SAS …
Chapter 37 The LIFETEST Procedure – Academics | | WPI, Chapter 37 The LIFETEST Procedure – Academics | | WPI, Proc lifetest data=data1 method= KM plots=survival(cb ATRISK TEST) time Time*Censor(0) strata Treatment / test=logrank run ODS GRAPHICS OFF 4) Adding ATRISK survival option will add a column that display number of subjects at risk and number of events at.
PROC LIFETEST computes the product-limit estimate for each stratum and tests whether the survivor functions are identical across strata. symbol1 c=blue symbol2 c=orange proc lifetest data=Exposed plots=(s,ls,lls) time Days*Status(0) strata Treatment run The PLOTS= option in the PROC LIFETEST statement is used to request a plot of, Both formulas involve Kaplan-Meier estimates (because you used the default, KM , of option METHOD= of the PROC LIFETEST statement), so to replicate the results you would need to compute these first or take the values from table Product-Limit Survival Estimates in the PROC LIFETEST output (or the corresponding output dataset if you specify the OUTSURV= option).
specifies the method used to compute the survival function estimates . Valid values for type are as follows. PL | KM . specifies that product-limit (PL) or Kaplan-Meier ( KM ) estimates are computed. ACT | LIFE | LT . specifies that life-table (or actuarial) estimates are computed. By default, METHOD=PL.
estimates . CONCLUSION All the datasets that are created in PROC LIFETEST and PHREG(_censorsum, _mean, _quartiles, _parmests, _wilcox1, and _logrank1) all need to be manipulated and combined. ID variables should be created for grouping and ordering purposes. A Label field should be created to display a statistic label for each outputted statistics.
