Regression analysis with Cost as outcome variable

[samraty81]

I am trying to predict the impact of readmission events (continuous) and type of readmission (medical, surgical, other) on total hospital costs. Because costs are skewed by nature, I am applying gamma distribution with log link function. Below is the model

PROC GENMOD data = abc;
class type (ref='medical') gender (ref='F')/param=ref;
model cost = event type age gender /dist=gamma link=log type3;
run;

1) Is the model correct?

2) How can I get marginal effects from the coefficients for different variables. i.e. is there a SAS option that will give me hospital cost within each level of type of readmission and for male and female?

3) I know modified park test will help us determine whether to use gamma distribution or not, but I can't seem to find that option in SAS.

[Ksharp]

1) check EFFECTPLOT statement
2)

http://blogs.sas.com/content/iml/2015/09/10/plot-distrib-reg-model.html

http://blogs.sas.com/content/iml/2015/09/16/plot-distrib-exp.html