Dividing Two Columns without denominator not changing

Hi again!

I have a table that contains a list of patients, called MASTER PATIENT [Patient ID].

I have another table that contains medical diagnoses by patients, date of service, and spend, called MASTER MEDICAL [Diagnosis, [Service Date] and [Spend]

For visual, here is a sample layout:

MASTER PATIENT

Patient ID                    Reporting Date

123456789                  1/1/2019

000000001                  1/1/2019

111111111                  1/1/2019

222222222                  1/1/2019

333333333                  1/1/2019

Here I have 5 patients in January 

MASTER MEDICAL

Patient ID            Diagnosis               Spend          Reporting Date

123456789          Asthma                   $500            1/1/2019

000000001          Cancer                     $24,500      1/1/2019

Here I have 2 patients, 2 diagnoses with a total spend of $25,000.

What I'm trying to do is divide $25,000 by the 5 patients in the MASTER PATIENT file; however, because there is a relationship between the two tables, it is dividing $25,000 by the 2 patients in the medical file. I have a slicer to show claims between 1/1/2019 and 12/31/2019.  So with this slicer, I have 5 patients who in total have spent $25,000.

My formula is the following:

Per Patient Per Year = CALCULATE(DIVIDE('MASTER MEDICAL'[Spend]),CALCUATE(DISTINCTCOUNT('MASTER PATIENT'[Patient ID])

I'm expecting a result of $5,000 per patient per year and not the $17,500 that it is producing (whereas $17,500 is $25,000 divided by the 2 patients in the MASTER MEDICAL file).

Any ideas?  Should I create a copy MASTER PATIENT and not have any relationships to any of the other tables?