Date: Wed, 21 Feb 2001 12:51:45 -0500 Klaus Lemke "SAS(r) Discussion" Klaus Lemke Re: calculating percents cc: Eileen_Farrelly@PCIT.COM <200102211601.LAA02159@ens1.is.jhsph.edu> text/plain; charset="us-ascii"; format=flowed

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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