| Date: | Wed, 21 Feb 2001 12:51:45 -0500 |
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| Reply-To: | Klaus Lemke <klemke@JHSPH.EDU> |
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| Sender: | "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU> |
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| From: | Klaus Lemke <klemke@JHSPH.EDU> |
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| Subject: | Re: calculating percents |
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| In-Reply-To: | <200102211601.LAA02159@ens1.is.jhsph.edu> |
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| Content-Type: | text/plain; charset="us-ascii"; format=flowed |
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Eileen Farrelly <Eileen_Farrelly@PCIT.COM> wrote:
>I would like to fully automate the following:
>
>I am calculating the percentage of patients for whom I have data on over
>the total population of the plan and I am calculating the per Member per
>Month cost (PMPM) (for a particular class of drugs).
>
>Among other variables I have the following:
>
>ptid date drug cost
>1 01/01/99 A 63.50
>1 02/01/99 A 63.50
>1 03/01/99 B 27.46
>2 02/03/99 C 45.20
>2 06/05/99 D 75.20
>3 08/02/99 A 57.64
>3 09/01/99 A 58.64
>3 10/11/99 B 35.00
>
>Although it is not in the data, I know the plan's total population to be
>(example) =50.
>
>I can get the number of unique patients using the following:
>
>data unique;
> set one;
> by ptid;
> if first.ptid;
>run;
>
>But then I have to calculate the percentage of unique patients over the
>total plan membership with my calculator - is there a way (using a macro?)
>that I can get the number of unique patients and divide it by the total
>plan population?
proc sql;
count ptid
into :tot_pop
from one; /* stores total population count into macro variable tot_pop */
count distinct ptid
into :tot_pop_uni
from one: /* stores number of unique patients into macro variable
tot_pop_uni */
quit;
%put tot_pop_uni/tot_pop;
>I have the same issue with calculating the PMPM.
>The formula is :
> PMPM=((SUM cost)/12)
> / plan's total population
>
>I can get the SUM of the costs using proc means but then I have to use the
>calculator to divide that by 12 and then divide by the total plan
>population.
output the sum into a dataset and divide by the total population:
proc summary data=one;
var cost;
output out=two sum=; run;
data two; set two; pmpm=(cost/12)/&tot_pop; run;
>I am trying to automate things so that SAS will directly output the
>computed values for me.
One thing to consider is that your calculation assumes 12 month
enrollees. Persons with less than a full year of enrollment should have
their costs annualized and the sum calculation should be weighted by months
of enrollment.
Klaus Lemke
Johns Hopkins School of Public Health
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