This is wrong for so many reasons, there's not enough room to list them all on this simple forum. However, there is a way to do this without causing the damage it'll do in the future. Create a calculated column that "feeds" off the PatientID column... Something like this...
ALTER TABLE Patient --Assuming your table name is "Patient" because you didn't say
ADD PatID AS 'PatID_'+CAST(PatientID AS VARCHAR(10))
It can also be indexed and used as an "Alternate key" for foreign key and performance reasons...
CREATE UNIQUE INDEX IXU_Patient_PatID
ON jbmTest (PatID)