A statement was put into my medical records?

After a hospital stay, colitis with dehydration, I saw my doctor and he said there was a recent note added to my medical record that I drink excessively. I asked him where that came from, and he just said it wasn't a medical person who made the comment. I don't drink excessively, but there is a family feud, and the charge has been leveled in the past by a family member through clenched teeth. I'm suspicious that this person called the doctor or hospital while I was a patient. They've laid the charge with anyone who will listen, and I wouldn't put it past them. Fortunately people know me and the smears haven't done any harm, but now having it mysteriously show up in my medical records is an escalation of hostilities I'm not going to put up with, if that's what's going on.

Is there any protection with your medical records for letting comments, quite possibly anonymous, become part of your permanent medical records? Are there any provisions requiring disclosure of how an item of information got into your permanent medical records? If I demand to know who said what, are they required to tell me?