Programming the statistical procedures from SAS

Two part model for health care costs

Occasional Learner
Posts: 1

Two part model for health care costs

Can anyone provide or direct me to SAS code for two part models in GLM.  I am analyzing cost differences between patients who have experienced a poisoning and those who have not.  There are lots of zeroes in the data and it is skewed. From what I've read, the first part of the model would be a logistic regression and the second would be a regression with a gamma distribution and log link.  I am especially interested in how to combine the results of the two regressions to develop estimates of cost differences between the two groups.

Grand Advisor
Posts: 16,906

Re: Two part model for health care costs

To get you started see the papers at


FYI - This is a good place to start research on any SAS topic Smiley Happy

SAS Employee
Posts: 29

Re: Two part model for health care costs

Try using PROC FMM:


Your SAS code should look something like this:


proc fmm data=rowdata;

  model response = age income avgexp / dist=binary;

   model response = age income avgexp / dist=gamma;

   model response = / dist=constant; 



The last MODEL statement specifies a constant distribution with all mass at zero for the zero target group.


To understand PROC FMM and finite mixture models take a look at:





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