Had to think about this for a while and I am agreeing with you, a blockchain technology made available to the public which give them access to medical records as well as the hospital's patients information has some bad sides that can lead to abuse. What I am thinking of is that these businesses related to the industry like drug manufacturers and health insurance companies will use this information for their own personal gain. For example insurance companies will raise their fees on an area where they know more accidents are happening or drug store companies can decrease their supply from one area which has very high demand on a specific drug which in turn will increase the prices. From what I know of this companies only have limited coverage on this kinds of information, giving them the whole information can really lead to abuse of the system.