Identifying the earliest date for a composite variable

[jennxxness]

I am a beginner SAS user and would really appreciate some help.

This is an example of the dataset I have for several thousands of patients:

Patient_ID	HF	HF_date	MI	MI_date	Stroke	Stroke_date
1	0	.	1	31DEC2019	1	06AUG2005

HF=Heart Failure, MI=Myocardial Infarction

I am working on a survival analysis and will need to do it for a composite outcome called MACE (which will the 3 variables in my dataset: HF, MI and stroke).

I am trying to find the best way to create a MACE_date that reflects the earliest date if a patient has more than 2 outcomes. So for patient 1 above, I would want the MACE_date to be 06AUG2005 instead of 31DEC2019.

I currently have:

MACE=0;

if HF=1 then MACE=1;

if MI=1 then MACE=1;

if stroke=1 then MACE=1;

MACE_date=.;

if HF=1 then MACE_date=HF_date;

if MI=1 then MACE_date=MI_date;

if Stroke=1 then MACE_date=Stroke_date;

How can I code my SAS in a way where if a patient has multiple outcomes (HF and MI and stroke), that the MACE_date will reflect the earliest date? Is there an easy way to do this?

Thank you so much in advance

[Reeza · Accepted solution]

MACE=0;
if max(HF, MI, STROKE) = 1 then MACE=1;


MACE_date=.;
if MACE =1 then MACE_DATE = min(HF_Date, MI_Date, STROKE_DATE);

Use the MIN/MAX functions. 

Your first condition can be simplified to checking if the max of any of the variables (assuming they take only ., 0, 1) are 1 and you can simplify the last portion to take the minimum. Missing values are ignored. 

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@jennxxness wrote:

I am a beginner SAS user and would really appreciate some help.

This is an example of the dataset I have for several thousands of patients:

Patient_ID	HF	HF_date	MI	MI_date	Stroke	Stroke_date
1	0	.	1	31DEC2019	1	06AUG2005

HF=Heart Failure, MI=Myocardial Infarction

I am working on a survival analysis and will need to do it for a composite outcome called MACE (which will the 3 variables in my dataset: HF, MI and stroke).

I am trying to find the best way to create a MACE_date that reflects the earliest date if a patient has more than 2 outcomes. So for patient 1 above, I would want the MACE_date to be 06AUG2005 instead of 31DEC2019.

I currently have:

MACE=0;

if HF=1 then MACE=1;

if MI=1 then MACE=1;

if stroke=1 then MACE=1;

MACE_date=.;

if HF=1 then MACE_date=HF_date;

if MI=1 then MACE_date=MI_date;

if Stroke=1 then MACE_date=Stroke_date;

How can I code my SAS in a way where if a patient has multiple outcomes (HF and MI and stroke), that the MACE_date will reflect the earliest date? Is there an easy way to do this?

Thank you so much in advance

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[jennxxness]

Thank you so much!