What is the biggest problem to day in the health Insurance world in the doctor-insurer-customer relationship?

I'm looking for some sources, have insurance companies been in court with doctors or clients about the lack of communication between all 3 parties?thanks
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The problem as I see it is that the insurance industry is dictating what the doctor can and cannot do for a patient regardless of the health outcome for the patient. The insurance company is looking at the bottom line. The doctor is looking at the patient. I've known a lot of people who were denied needed medical tests or surgeries simply because the insurance company refused to pay for them.
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