Medly is the medical app I built part of. It's at https://medly.ca. I wrote the first Android version of the mobile app, and hired most of the team that now maintains it.
Initially for heart attack patients (sick enough to need monitoring but not needing a hospital bed post-recovery), we send them home with a smartphone and some medical devices (bluetooth). Each morning the app guides them through all measurements; when collected, sends them all to the hospital server This server runs an algorithm designed by Head of Cardiology at Toronto General Hospital. If a patient is not self-caring adquately, they get a phone call from the head of cardiology, and, presumably, a lecture :-).
We have a journal paper on how this approach not only reduces healthcare costs, but by reducing "readmissions" (subsequent heart attacks, a ride in the van with the flashing lights, etc.), saves lives.
Probably the most rewarding app I've worked on.
This work was done at Toronto General's Centre for eHealthInnovation, where I also worked on breathe, ned, and other apps.