For good or ill, The start-up ideal is generally to solve problems broadly, to disrupt an entire industry rather than build one more extension to that industry.
The problem of integration, of conforming to byzantine standards and to the mess that overall existing health IT, is itself still just a detail in the overall problem of health and technology.
The fundamental problem is the messiness and unpredictability of physical human bodies/human health.
The reason that health records are a mess is that there is no easy to way to universally classify "what is going on" with a given person in a cut-and-dried fashion. For any field of a health record, there is significant gray areas once you get to a large scale (including "basic" things like "male" and "female").
Just as much, health procedures often don't benefit from automation because what one person does to care for another person is subtle and not easily codified.