Re: How to Customize SGPLOT for KM plot

SASuserlot · Posted 11-09-2021 02:41 PM

I am learning SGPLOT to output the KM plots recently, I have some questions how to customize the Kaplan plot output. I tried to achieve it using the sas documentation, but I am not able to achieve it. I have the questions mentioned in the image. Can you guys please help me to learn the things, also please direct any good references. Thank you in Advance


**Dummy data**;

data adtte;
   length paramcd $8 param $100;
   paramcd = "OS";
   param = "Overall Survival";
   do trtpn = 1 to 4;
      trtp = 'Treatment ' || put(trtpn,1.);
      do subjid = 1 to 40;
         aval = 2 + ranuni(1)*24*(trtpn/4);
         cnsr = (ranuni(1)>0.2);
         output;
      end;
   end;
run;

proc sort data=adtte out=km00;
   by trtpn trtp;
   where paramcd = "OS";
run;
proc sql noprint;
   select   distinct strip(param) || " Probability"
   into     :ylabel
   from     km00
   ;
quit;
%let ylabel = &ylabel;
%put &=ylabel;

* creating tick marks on X-axis*;
%let values = 0 2 4 6 8 10 12 14 16 18 20 22 24;
%put &=values;

**format the value 0 as B/L**;
proc format;
   value timefmt
   0 = "B/L"
   other = [best.]
   ;
run;
ods html;
**lifetest**;


ods graphics on;
ods listing close; 

proc lifetest data=km00 plots=(survival(atrisk=&values));
   ods output survivalplot=km10;
   time aval*cnsr(1);
   strata trtpn;
run;

**complete with a format to prevent missing values from showing up as a dot.**;
proc format;
   value xatn
   . = " "
   other = [best.]
   ;
run;

data km20;
   set km10;
   if n(tatrisk) then
      xatn = atrisk;
   format xatn xatn.;
run;

****************************************************************************
Next we add the xaxistable statement. For some reason SAS has us use the 
class= option to create groups in the x-axis table (we use the group= option 
in the step and scatter statements).
*****************************************************************************;
proc sgplot data=km20;
   *--- draw the survival curves ---;
   step y=survival x=time / 
      group=stratumnum
      name="step"
      ;
   *--- draw censor indicators for censoring symbol legend purposes ---;
   scatter y=censored x=time /
      markerattrs=(symbol=circle )   
      name="censor"
      ;
   *--- draw censor indicators ---;
   scatter y=censored x=time /
      group=stratumnum 
      markerattrs=(symbol=circle)
 		;

	*--- add the sample sizes ---;
   xaxistable xatn /
      class=stratumnum
      colorgroup=stratumnum
      ;

   *--- cosmetics ---;
   yaxis
      label="&ylabel"
      ;
   xaxis 
      values=(&values) 
      valueshint
      valuesformat=timefmt.
      label="Weeks" ;

	**--Key legend--> Main heading--**;

   keylegend "step" /
      title="Treatment Group"
      noborder
      linelength=15pct
      outerpad=(bottom=10pt)
      ;
   **---Location of the Censor legend indicator--**;
	  keylegend "censor" / 
      location=inside
      position=bottomleft
      ;
run;