The missing entities

There’s a reason why our medical records systems don’t work and that reason goes back quite a way. As I’ve mentioned before, it goes back to when IT people started implementing the paper records in computers, assuming the paper records contained a complete model of the medical management of the patient, which they didn’t. Automating that crippled model resultet in an automated crippled medical records system. All general medical records systems I’ve ever seen are based on a model somewhat like this:

As you can see, it’s a mess in general, but the problem I’m particularly focusing on is that the main entity, once the patient has been chosen, is the “Encounter”. Everything then dangles of either the encounter or the patient, making it totally impossible to find anything. If you search for information under the patient, you’ll find everything, but if you search under encounters, you’ll typically find nothing. For example, if I want to know if the patient ever said something in particular, or ever showed a particular clinical sign, I first have to know during which encounter that thing happened, if it ever happened. But if I knew that, I wouldn’t need to search for it, would I? Oh, by the way, did you see where they put the symptoms or diseases the patient has? No? Well, neither do I, because they didn’t. It’s not there. The ICD-10 codes don’t fill that function.

This entity relation diagram (ERD) is nuts. Not even a rank beginner would normally analyze a domain this poorly. But somehow it happened and keeps happening.

Let’s see how it should look:

Now we’re getting somewhere. A patient has issues, for which we, in turn, follow clinical guidelines, treat with medicines which in turn are refilled using prescriptions. Referrals are for issues, not for patients as in the first, bad, analysis. With this ERD as a basis, everything else falls into place. There are hundreds of entities missing in these two diagrams, but adding them to the correct, second, diagram is pretty easy and doesn’t break anything. Not so for the first ERD, the one we see in all current systems.

I actually made these two simplified diagrams for the iotaMed wiki. If you want to improve on them, please do that there. That’s what wikis are for.