Hi,
I have a data set that contains Patient IDs, Drugs, and date of the prescription fill. I am trying to identify the number of individual patients that were on a drug in a given year. A patients typically have multiple records within a year, as each record representation a prescription fill date. The data structure looks like this:
Patid | DrugName | Year |
100 | Drug 1 | 2013 |
200 | Drug 1 | 2013 |
200 | Drug 1 | 2013 |
200 | Drug 1 | 2013 |
200 | Drug 1 | 2013 |
300 | Drug 1 | 2013 |
100 | Drug 1 | 2014 |
300 | Drug 2 | 2013 |
100 | Drug 2 | 2015 |
400 | Drug 2 | 2015 |
400 | Drug 2 | 2015 |
400 | Drug 2 | 2015 |
300 | Drug 3 | 2014 |
300 | Drug 3 | 2015 |
100 | Drug 3 | 2015 |
In my head, the output should should look something like this:
Drug | year | #Patients |
Drug 1 | 2013 | 3 |
Drug 1 | 2014 | 1 |
Drug 2 | 2013 | 1 |
Drug 2 | 2015 | 1 |
Drug 3 | 2014 | 1 |
Drug 3 | 2015 | 2 |
I have tried proc summary, but that just gives me a frequency of the number of records, by drug & year. I am thinking proc sql using count/distinct would work, but not sure how to group by drugname & year, as I am not very good at this...
Any assistance is greatly appreciated.
Thanks!
Chris
You can do that but I'd consider a different method because you are likely to want multiple stats.
data have2;
set have;
by id drug;
First_Drug=0;
if first.drug then First_Drug=1;
run;
proc means data=have2 sum;
class year drug;
var first_drug;
output out=want sum(first_drug) = num_patients;
run;
Thanks. This worked well, and matches up with another step in my analysis.
-Chris
PROC FREQ is pretty good at counting:
proc freq data=have;
tables DrugName*PatID*Year / noprint out=summarized;
run;
proc freq data=summarized;
tables DrugName*Year / list;
run;
The frequency column in the final PROC FREQ will be the patient count. Also note, the second PROC FREQ could create an output data set if needed.
Don't miss out on SAS Innovate - Register now for the FREE Livestream!
Can't make it to Vegas? No problem! Watch our general sessions LIVE or on-demand starting April 17th. Hear from SAS execs, best-selling author Adam Grant, Hot Ones host Sean Evans, top tech journalist Kara Swisher, AI expert Cassie Kozyrkov, and the mind-blowing dance crew iLuminate! Plus, get access to over 20 breakout sessions.
Learn the difference between classical and Bayesian statistical approaches and see a few PROC examples to perform Bayesian analysis in this video.
Find more tutorials on the SAS Users YouTube channel.