HIPAA wasn’t thought of for forty years after that book was archived.
There is a lot of misunderstanding about HIPAA. It doesn’t matter that the HIPAA law didn’t exist then, it exists now and covers prior events. HIPAA “protected health information” includes the fact that medical care was rendered to a specific person. So yes, a patient log is protected information. Even if it was generated before the HIPAA law was passed.
It is my understanding that HIPAA was created because Bill Clinton has Herpes. He resented the White House Doctor asking him what he needed a specific prescription for. He fired the Doctor, and appointed one of his own. (This was during the Transition period when Bush's White House doctor was still there.)
Clinton was very sensitive about all the nasty diseases he carried, and so he pushed for legislation making the disclosure of medical information illegal. (Also AIDS patients represent a big chunk of the Democrat party.)