To answer your question, try looking up Medrec when it comes to health care. Most of the research is done towards dealing with keeping the data off the chain. In addition, there are other blockchains that might provide a better solution, for more privacy. Such as, try looking up the quorum by JP Morgan. There is various type of formats that are being looked at but these can give you two possible solutions. Also, check out Health Nexus' whitepaper, which deals with medical blockchain technology. Let me know if you need more links. Have shared one below for your help!!