Does anyone's insurance actually cover 90 days residential? Aetna keeps saying "medical necessity"

We went through this in the spring. What worked: the center's utilization-review person requested a 'peer-to-peer' review — their clinical director talking to the insurer's doctor directly, with documentation of continued symptoms and a relapse history. Ask your center: 'Who on your team handles UR, and will you request a peer-to-peer?' If they don't have a real answer, that tells you something. Also ask the insurer for the denial IN WRITING with the clinical criteria they used — appeals get real once things are on paper.