Re: st: Handling pharmacy data with multiple entries per subject

[Phil Schumm <pschumm@uchicago.edu>]

On Jun 10, 2011, at 2:59 PM, Doernberg, Sarah wrote:
> I have a dataset from our pharmacy with prescriptions for  
> antibiotics in hospitalized patients. Each time a patient was  
> transferred (from the emergency department to the ward or the ward  
> to the ICU, for instance), a new prescription (and thus, a new row)  
> was generated. This is compounded by the fact that some people  
> received intermittent dosing (each start date with it's own row).
>
> Because this is a very large set of data, I am trying to figure out  
> how to have Stata combine the rows. Ideally, I would like to have  
> one entry per person with consecutive courses of antibiotics  
> represented by start and stop days (for example, someone who  
> received an antibiotic from 6/1-6/3 and 6/7-6/9 would have  
> start_date_1 = 6/1, stop_date_1=6/3 and start_date_2=6/7 and  
> stop_date_2=6/9).
>
> I have tried doing this with the collapse command but the best I can  
> do is to get total days on antibiotic in a given month. Converting  
> from long to wide also is not ideal because consecutive courses are  
> not combined due to the multiple prescriptions based on location.


You'll have to be a bit more specific here to get the help you're  
asking for.  For example, why do you want

    start_date_1   stop_date_1   start_date_2   stop_date_2
    ------------   -----------   ------------   -----------
        6/1            6/3           6/7            6/9

I'm guessing (but I could be wrong) that your next step after this  
will be to do some further calculations, which can probably be done  
more easily with the data in the original, long format.  Also, if you  
want help with the code to translate between what you have now and the  
layout above, then you need to show the actual layout of the current  
dataset.  Otherwise, people will just guess, and the whole exercise  
becomes quite inefficient.

Don't be put off by this -- I do calculations like this all the time  
in Stata, and it is very easy to do once you know how.  So chances  
are, this is definitely worth persisting with.


-- Phil

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