# Treatment Fees in Markov Model

Dear TP modelers:

I am building a Markov model to compare screening test strategies. If the patients receive treatment, there will be initial fees and annual fees. All the patients under treatment only pay one initial fee at the start of the treatment. However, if I put this variable into the model, does that mean each time the patient comes into the state, he will have to pay the cost once again? Thus, I wonder how I can insert an initial fee into the model.

Thank you,

Best Regards

• Official comment

Markov model values are built to support different values for the first cycle and all subsequent cycles, so you don't need another state.

Let's say you have 2 variables in your model for these costs.

• cScreening (first cycle only)
• cMeds (every cycle)

Then in the health state, you would use these variables as follows...

• Initial Cost: cScreening + cMeds
• Incremental Cost: cMeds

When you run Markov Cohort Analysis for the full Markov process (at the Markov node), you will be able to check the costs in _stage 0 and all subsequent cycles.

• The initial fee can be placed in the initial cost box which will only be evaluated when _stage = 0. Otherwise, assuming that your cycles are monthly, the annual fees can be entered into the incremental box as if(modulo(_stage;12)=0;annualFee;0). Modulo is integer division with a remainder: modulo(11;12) = 11, modulo(12;12) = 0, modulo(13;12) = 1....modulo(23;12) = 11, modulo(24;12) = 0 etc. So modulo(_stage;12) = 0 is true every time _stage is a multiple of 12.

Of course, you'll probably want to discount annualFee