hhhmmm I'm pretty sure she is his attending now mainly because in Wilson's Heart she was the doctor working with Taub and I think I remember once seeing, when there was a close up of House's hospital wristband, Dr. Cuddy as the attending.
She was his doctor in the past, but now that she's an administrator she doesn't actually do much doctoring these days. She definitely makes sure he's taken care of, though. And my guess would be that she's his medical proxy now.
