Earlier quoted context omitted.
This is not true. I'm not a lawyer, but I am in the healthcare field. HIPAA very much applies to this type of app or any other type of app that may deal in personally identifying information (PII) related to healthcare.
I was too. https://www.hhs.gov/hipaa/for-professionals/covered-entities...
Edit: If no healthcare provider has access then maybe it could skate by. I interpreted "any user making notes to your account" to mean healthcare providers would have access. Even if not, they should still seek legal counsel. And this app is literally promising safety and security of healthcare information.