Merging two KM Survival Curves into one image

[kmardinian]

Hi, I am working out of SAS Studio and have two different excel datasets I created two KM Survival curves for. For presentation purposes, I wanted to know whether there was a way to have both curves show up in one image so it's easier to compare the two. 

Here is the code I have been using so far:

PROC IMPORT DATAFILE="/folders/myshortcuts/SAS_filesUSB/ConcordantKRAS.xlsx"
OUT=ConKRAS
DBMS=XLSX
REPLACE;

Data Survival;
Set ConKRAS (Keep= status SurvivalTime);
run;

Proc Freq;
Tables SurvivalTime STATUS ;
run;

Proc Lifetest Data=Survival Method=KM Plots=(s) Censoredsymbol= '|';
Time SurvivalTime*STATUS (1);
run;

PROC IMPORT DATAFILE="/folders/myshortcuts/SAS_filesUSB/DiscordantKRAS.xlsx"
OUT=DisKRAS
DBMS=XLSX
REPLACE;

Data Survival1;
Set DisKRAS (Keep= status SurvivalTime);
run;

Proc Freq;
Tables SurvivalTime STATUS ;
run;

Proc Lifetest Data=Survival Method=KM Plots=(s) Censoredsymbol= '|';
Time SurvivalTime*STATUS (1);
run;

Any help is much appreciated!

[Reeza · Accepted solution]

Read in both data sets - with different names. 

Append them using a data step and add a variable that indicates the source data set.

Use that as the STRATA variable - AND CHECK THAT THEY'RE the same. I think the calculations are independent with strata's but I can't recall so you should definitely verify that. Untested/unverified.

PROC IMPORT DATAFILE="/folders/myshortcuts/SAS_filesUSB/ConcordantKRAS.xlsx"
OUT=ConKRAS
DBMS=XLSX
REPLACE;

PROC IMPORT DATAFILE="/folders/myshortcuts/SAS_filesUSB/DiscordantKRAS.xlsx"
OUT=DisKRAS
DBMS=XLSX
REPLACE;
run;

Data Survival;
Set ConKRAS (Keep= status SurvivalTime) diskRAS(keep=status survivalTIme) indsname=source;
dsn_name = source;
run;

Proc Lifetest Data=Survival Method=KM Plots=(s) Censoredsymbol= '|';
Time SurvivalTime*STATUS (1);
strata dsn_name;
run;

[kmardinian]

Thank you so much, that definitely makes sense! But for some reason when I run this code, SAS doesn't recognize my variables in the keep statement

LOG:

1 OPTIONS NONOTES NOSTIMER NOSOURCE NOSYNTAXCHECK;

61

62 PROC IMPORT DATAFILE="/folders/myshortcuts/SAS_filesUSB/ConcordantKRAS.xlsx"

63 OUT=ConKRAS

64 DBMS=XLSX

65 REPLACE;

66

NOTE: The import data set has 380 observations and 26 variables.

NOTE: WORK.CONKRAS data set was successfully created.

NOTE: PROCEDURE IMPORT used (Total process time):

real time 0.15 seconds

cpu time 0.13 seconds

67 PROC IMPORT DATAFILE="/folders/myshortcuts/SAS_filesUSB/DiscordantKRAS.xlsx"

68 OUT=DisKRAS

69 DBMS=XLSX

70 REPLACE;

71 run;

NOTE: The import data set has 528 observations and 26 variables.

NOTE: WORK.DISKRAS data set was successfully created.

NOTE: PROCEDURE IMPORT used (Total process time):

real time 0.18 seconds

cpu time 0.18 seconds

72

73 Data Survival;

74 Set ConKRAS (Keep= status SurvivalTime) diskRAS(keep=status survivalTIme) indsname=source;

ERROR: The variable status in the DROP, KEEP, or RENAME list has never been referenced.

75 dsn_name = source;

76 run;

NOTE: The SAS System stopped processing this step because of errors.

WARNING: The data set WORK.SURVIVAL may be incomplete. When this step was stopped there were 0 observations and 3 variables.

WARNING: Data set WORK.SURVIVAL was not replaced because this step was stopped.

NOTE: DATA statement used (Total process time):

real time 0.00 seconds

cpu time 0.00 seconds

77

78 Proc Lifetest Data=Survival Method=KM Plots=(s) Censoredsymbol= '|';

79 Time SurvivalTime*STATUS (1);

80 strata dsn_name;

ERROR: Variable DSN_NAME not found.

81 run;

NOTE: The SAS System stopped processing this step because of errors.

NOTE: PROCEDURE LIFETEST used (Total process time):

real time 0.00 seconds

cpu time 0.00 seconds

82

83 OPTIONS NONOTES NOSTIMER NOSOURCE NOSYNTAXCHECK;

96

Do you know why that is? Thank you!

[Reeza]

72

73 Data Survival;

74 Set ConKRAS (Keep= status SurvivalTime) diskRAS(keep=status survivalTIme) indsname=source;

ERROR: The variable status in the DROP, KEEP, or RENAME list has never been referenced.

75 dsn_name = source;

76 run;

NOTE: The SAS System stopped processing this step because of errors.

WARNING: The data set WORK.SURVIVAL may be incomplete. When this step was stopped there were 0 observations and 3 variables.

WARNING: Data set WORK.SURVIVAL was not replaced because this step was stopped.

NOTE: DATA statement used (Total process time):

real time 0.00 seconds

cpu time 0.00 seconds

I used the code you provided, which indicated the variable names was 'status' in both data sets. If your code ran before it should run now, but this is a variable name issue. You can verify the variable names and ensure that you have the correct names and variables to combine the data - they need to be the same type to be able to combine it. 

[kmardinian]

That was an oversight on my part, sorry! It is working now, thank you so much!