That’s incorrect. HIPAA allows phone book data (i.e. directory information that is publicly available) to be released. That doesn’t mean that a hospital can confirm that a patient has been admitted.
It's not phone book data, it's hospital directory information: Read and learn:
"HIPAA's Privacy Rule allows inpatient health care facilities to continue to maintain "directories" of current patients, but restricts the information in them to the following: name; location in the facility; "condition described in general terms, that does not communicate specific medical information"; and religious affiliation. Except for religious affiliation, the information may be disclosed to anyone who asks for the individual by name. link to source