The big point of the Project is that it is expandable to various database areas, from various sectors, from a simple positive register in Credit Companies, Health Plans and the like, to even more confidential data for financial use, these are already explored by Companies and People who should keep secrecy, then we have that power. Datum is great and we will still hear a lot about its concept
I don't think that this project can use for Health Plans. Patient's data is secret, how can hospital transfer it? They need the patient's permission. But I think the patients will not agree.
Actually, there are health providers that are looking into hospital data protection. The marketplace idea evolved from the fact that Datum was originally designed as a secure storage. You could have a health institution encrypting all the data (unlike "safe storage" like Equifax, or SEC), and providing keys to just the patient, hospital and the insurer of the said patient.
If the patient does not agree to have his data shared, hospital cannot sell that user's data to another insurer, which is a common practice (how many advertisements for competing health insurance plan you receive daily? That does not come from pixie dust, that comes from insurers buying off data that contains your name, age, location and current health plan). From whom do insurers buy data... not exactly a secret, right?
The only patient data that is (in theory, at least) really secure is an actual diagnosis and test results. Don't see who would want to share that... unless you want to get in a special alpha or beta medical trials designed by the healthcare industry.