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04-20-2017 09:07 AM

Hello everyone,

I am working on survival data with incidence of cancer and some food consumption data in quartiles.

Exposition : quartile of sugared food

Confusion factor : age, BMI, sex.

Outcome : cancer

I would like to draw a curve of cumulative hazard rate function (for example with Nelson Aalen estimator, a non parametric estimator of the cumulative hazard rate function) like this graph below : where we would see the cumulative risk of cancer in function of the 4 quartiles of food consumption.

Caption of the graph : "Nelson-Aalen curves showing the outcome of new-onset overweight depending on ultraprocessed food consumption at baseline. Adjusted for sex, age, marital status, educational status"

If someone had an idea of a beginning of script, i would be really grateful.

i am doing Cox model with this type of script :

```
proc phreg data=mydata;
class sexe;
model survival_time*censure(1)=sexe age IMC;
strata quartile_ultraprocessed ;
run;
```

Thanks in advance, have a nice day,

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04-20-2017 04:49 PM

Have you tried adding the PLOTSooption to your PROC statement?

You'll want tthe 'statistical' style to get the curves in a similar format but you'll have to manually add the data at the top. If you can post it at the bottom of the graph that could be more easily incorporated.

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04-26-2017 10:30 AM

You can get the cumulative hazard (Nelson Aalen) by using the baseline statement in PHREG;

As Nelson Aalen only can account for one combination of covariates at a time you will need to put all covariates into the strata statement.

Here is a simple example:

```
data test;
do i=1 to 100;
x=mod(i,2);
t=rand('exponential',1);
output;
end;
run;
proc phreg data=test;
model t=;
strata x;
baseline out=baseline cumhaz=cumhaz;
run;
```

You can then plot the hazard by using proc gplot or sgplot.

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04-27-2017 06:26 AM

thanks for your answers.

I tested your statements but I don't know why when I look at the table "baseline" created and containing "Cumulative Hazard function estimates", there are only about 2000 observations. And in my dataset of departure, I have about 100 000 observations (about 2200 events and 97 800 censored). Do you have an idea why I have this decrease ?

have a nice day,

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04-27-2017 06:38 AM

the estimated cumulative hazard function only has as many jumps (its a step function) as there are uncensored events. So wiht 2200 events it should have 2200 observations.