Patient.PatientId should be a foreign key to User.UserId. Patient table should not have a separate UserId column.

[sencode]

Instead of having PatientId being an autogenerated primary key for Patient table, and having UserId as a foreign key to User.UserId,

delete the column UserId from Patient table, and make PatientId both the primary key as well as the foreign key to User.UserId. Do not autogenerate PatientId, simply copy the value from the User.UserId table.