Medicine is a data processing business. Doctors measure, notice and inspect, and based on the data they collect, make decisions and take action.
Alas, despite years of promises, online data storage in medicine is a mess. Whenever I visit a new doctor, I have to start over, from the beginning, to the best of my recollection. And I hate forms, so I leave stuff out, or forget things, or my handwriting is a mess.
Perhaps we shouldn't wait for a universal solution.
This simple Word doc (Download file) (Google doc) will take you a few minutes to fill out. And, as you get older, you can keep it up to date. Every time you go to a doctor's office, print it out and bring it with you. Keep one where you can find it. Make sure your kids or parents have a copy as well. (And, while you're at it, forward a blank one or this post to people who will benefit from having one.)
No cloud security issues, no data format issues. An old-fashioned, paper-based sneakernet of your medical information. Over time, doctors will tell you what you should add or leave out for the next doctor, as you take charge of doing a better job of telling your doctor what your doctor needs to know.