Re: [Gnumed-devel] Medication viewing

[Jim Busser]

On 2009-10-23, at 4:07 AM, Karsten Hilbert wrote:

> > The universe of what is relevant for a patient could include
> >
> > a. what they had *ever* taken
>
> There's a full audit trail which carries this information.

Once a row has been created in the medication listing, it can display  
the {drug, dosage, schedule} as it was last known to be taken by the  
patient. However the simple existence of an item

        acetylsalicylic acid 81mg daily

created three years ago and which needs no prescription does not mean  
the patient continues to take it. Maybe nine months ago their surgeon  
directed it to be stopped a week before surgery and no-one ever made  
clear that it was supposed to be restarted. This is an inverse of the  
allergy situation where just because "No allergies" was true when  
asked 5 years ago it is worth verifying from time to time (if not  
every visit) and maybe capturing this verification. Can I attract us  
to a medication column

	last_confirmed (date, maybe NULL is ok in a case where the  
information was pre-entered from documentation and it turns out the  
patient says "no, that's wrong")

??

The end result is a set of rows that always contains the last-altered  
version. At discontinuation, the row could be updated to reflect when  
a patient last used it, as well as the reason for discontinuation  
which could be any combination of not needed, not tolerated or not  
effective. But unless a row can be deleted:
- the rows will always represent a mix of current and no-longer used  
medications (i.e. not just current medications)
- the rows will not offer a complete history (as some alterations  
would be in the audit file).

So.. the "current medications" might more correctly be seen as a  
partial index of drugs that the patient did, at some point, take and  
*may* currently be taking. For drugs that are no longer being taken,  
we could see the most-recent regimen as last-used. But a key  
dependency as to whether it is a complete index is whether, upon  
changing the strength of a drug (or changing brands), the doctor  
discontinued an existing row and added another or just made the  
alteration inside the row. That affects whether it is an inventory of  
*medications* that the patient has used, or medication *regimens* that  
the patient has used. I imagine that for this table we are preferring  
medications, but a regimen that mixes different strengths maybe has to  
be handled in two rows. Failure to do so might greatly complicate  
later efforts to administer the supply (prescribing).

At the point where in future we will want to view the total history of  
any drug, will it be no trouble to query-combine information from the  
current medication table with information taken from an audit table (I  
am supposing the audit table constraints would protect against  
inappropriate alteration)?