topic Re: Survival curves-Observed vs Expected in Statistical Procedures

Survival curves-Observed vs Expected

gunnerhenry — Sat, 29 Dec 2018 19:12:50 GMT

I'm trying to get "observed survival curves" from standard Kaplan Meier curve using PROC LIFETEST and "Expected or Predicted Survival curve" using PROC PHREG in the same graph. Can anyone help me how to do this. I'm using base SAS 9.4 but have access to the whole SAS suite if needed.

"Predicted survival" code

proc phreg data = mydata plots(overlay)=survival;
model time*event(0) = Age HTN platelets/ rl ties = efron;
baseline out = pred1 survival = _all_ ;
run;

"Observed survival" code

proc lifetest data=mydata outsurv=km1 plots=s;
time time*event(0);
run;

Thanks

Re: Survival curves-Observed vs Expected

Reeza — Sat, 29 Dec 2018 20:24:33 GMT

To do this you need to capture the raw data used to create the curves and then plot them on your own. Fortunately this is relatively easy.

1. Capture output from each proc

2. Merge or append the data sets

3. Plot using SGPLOT - use two different STEP statements so it doesn't matter too much how the merge happens.

For #1

https://blogs.sas.com/content/iml/2017/01/09/ods-output-any-statistic.html

For #2

https://video.sas.com/detail/video/4572997800001/merging-sas-tables-in-a-data-step?autoStart=true&q=merge

For #3

https://blogs.sas.com/content/graphicallyspeaking/2018/02/19/survival-plot-twist-using-sgplot-procedure/

@gunnerhenry wrote:

I'm trying to get "observed survival curves" from standard Kaplan Meier curve using PROC LIFETEST and "Expected or Predicted Survival curve" using PROC PHREG in the same graph. Can anyone help me how to do this. I'm using base SAS 9.4 but have access to the whole SAS suite if needed.

"Predicted survival" code

proc phreg data = mydata plots(overlay)=survival;
model time*event(0) = Age HTN platelets/ rl ties = efron;
baseline out = pred1 survival = _all_ ;
run;

"Observed survival" code

proc lifetest data=mydata outsurv=km1 plots=s;
time time*event(0);
run;

Thanks

Re: Survival curves-Observed vs Expected

gunnerhenry — Sun, 30 Dec 2018 01:12:46 GMT

Thank you! This worked to get what I needed to do. Appreciate your help.