topic Re: Calculating incidence rate in New SAS User

Calculating incidence rate

Ogee — Tue, 27 Apr 2021 11:12:40 GMT

Hello,
Please I need help with my data structure and calculating adjusted incidence rate with CI to output on a linear trend graph. Please see below for my current data structure which is a unique ID level dataset with millions of records:
ID YEAR EVENT FOLLOW-UP
1 2006 1 50
2 2006 0 100
3 2014 1 60
4 2006 1 20
5 2011 1 110
6 2006 0 10
7 2008 1 150
Below is the dataset I want in order to calculate incidence rate per person-time (i.e. follow-up x # of persons), including 95% CIs with Poisson regression:
YEAR #OF PERSONS EVENT FOLLOW-UP
2006 4 2 720
2008 1 1 150
2011 1 1 110
2014 1 1 60
Please any help with this and how to output the incidence rate and 95% CI unto a linear trend line plot (x-axis= year and y-axis = incidence rate).

Data structure and calculating event rates

Ogee — Tue, 27 Apr 2021 10:55:14 GMT

Hello,

Please I need help with my data structure and calculating adjusted incidence rate with CI to output on a linear trend graph. Please see below for my current data structure which is a unique ID level dataset with millions of records:

ID YEAR EVENT FOLLOW-UP

1 2006 1 50

2 2006 0 100

3 2014 1 60

4 2006 1 20

5 2011 1 110

6 2006 0 10

7 2008 1 150

Below is the dataset I want in order to calculate incidence rate per person-time (i.e. follow-up x # of persons), including 95% CIs with Poisson regression:

YEAR # OF PERSONS EVENT PERSON-TIME

2006 4 2 720

2008 1 1 150

2011 1 1 110

2014 1 1 60

Please any help with this and how to output the incidence rate and 95% CI unto a linear trend line plot (x-axis= year and y-axis = incidence rate).

Re: Calculating incidence rate

PaigeMiller — Tue, 27 Apr 2021 11:14:46 GMT

In your output, how is the 720 on row 1 calculated from the original data?

Re: Calculating incidence rate

Ogee — Tue, 27 Apr 2021 11:22:11 GMT

It is calculated as the number of days since the cohort entry year until last day of follow up for each person, and then summed up for all persons in each year. So I'm wondering, first, how do I aggregate the total persons each year so I get a year-level dataset.

Re: Data structure and calculating event rates

maguiremq — Tue, 27 Apr 2021 14:32:07 GMT

This gets you the data set that you want, and it also provides the plot. You're probably going to need to do the regression to get those results that you need.

proc sql;
	create table 	want as
		select	
					year,
					count(id) 								as num_persons,
					sum(event)								as event_sum,
					sum(follow_up) * calculated num_persons as person_time
		from
					have
		group by
					year;
quit;

proc sgplot data = want;
	series x = year y = person_time;
run;

Obs year num_persons event_sum person_time 
1 2006 4 2 720 
2 2008 1 1 150 
3 2011 1 1 110 
4 2014 1 1 60

Note, you could also use PROC SUMMARY or PROC MEANS, and maybe even PROC UNIVARIATE to get the same results. It just seemed a little easier in my head to do it with PROC SQL since it required some calculations. The regression may output plots if you request it.

Re: Calculating incidence rate

Reeza — Tue, 27 Apr 2021 15:24:30 GMT

FYI - I have merged your multiple posts. Please post your question only once.

Re: Data structure and calculating event rates

Ogee — Tue, 27 Apr 2021 20:49:46 GMT

Thank you so much for sharing this code and it works great 🙂 !

Re: Calculating incidence rate

haoduonge — Wed, 12 May 2021 18:53:48 GMT

2006 should 180, not 720 right?