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Posted 01-21-2020 07:28 PM
(9485 views)

Hi,

Can someone please help me with this question about how to compute IRR.

From my dataset, I have calculated crude incidence rates for cases and controls using (numbers of events/ total person-years for each group).

And now I want to know if this association is significant.

I have a dataset with cases and controls according to disease status. For each ID I have

1.case/control status (1/0),

2. person-years contributed by each id

3. log person-years contributed by each ID

4. and number of events per ID.

Can someone please explain how can I calculate IRR and test for significance or if any more steps are needed? I have the log person-years variable because I was trying to run proc genmod but couldn't find information on how to run it in context of incidence rates.

I will be happy to provide more detail if needed.

Thankyou.

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There is a function FINANCE('irr', ) .

Or could try older function IRR() .

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Thanks, Ksharp. I am looking into this as well

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- Tags:
- rate ratios
- rates

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Thank you, Statdave

I went over the link that you had sent. Can you please clarify what is "ln" in the offset statement? In the document, it is mentioned that

"ln = log(n)"

In which case is it the log of the total person-time contributed by the entire cohort (cases and controls)? or the logs of the total person time contributed by each individual?

Here is the code that I have changed according to my data.

proc genmod data=mydata; class disease exposure; model outcome = disease exposure / dist=poisson link=log offset=(what is this?); run;

I understand that I have to make some assumptions about the distribution of the outcome before I run this.

I appreciate your help.

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It worked, thank you for the clarification.

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