The PAAB code applies to Canadian companies or to companies targeting content to Canadian healthcare professionals and patients. Please see the Health Canada document “The Distinction Between Advertising and Other Activities” for further clarification on how the content and role of the sponsor may impact if a piece is considered advertising.
In the example provided in your question, a truly disease state only piece with no messaging about treatment and no direct or implied link to a product the sponsor has a vested interest in, may be exempt from PAAB review. There are variables that could render the piece subject to review (e.g. focusing on a disease mechanism of action for which only exogenous compounds target or are being developed to target; inclusion of a link to a brand page or treatment-related information, etc.). Another note of caution is that this would likely be considered direct to consumer advertising and would be subject to consumer regulations as well.