There are three scales. Practices along the bottom, items dispensed along the left and represented as a line chart, and cost along the right shown as bars.
From the Xmas edition of Exeter PCT Prescribing Advice Department's Drug Talk newsletter.
Consider this Graph of Dianette use or cost by Practice in Exeter. Since not everyone else is yet happy about showing their figures to the world I've erased the names of the practices except mine:-
There are three scales. Practices along the bottom, items dispensed along the left and represented as a line chart, and cost along the right shown as bars.
From the Xmas edition of Exeter PCT Prescribing Advice Department's Drug Talk newsletter.
Therefore, unsurprisingly, a particular Practice with a big population of students (who commonly have acne and sex) gets a high rate of Dianette per ASTROPU, and another Practice where many many residents are elderly gets a low rate...not because of any difference in the doctors, or the patients who take Dianette, but because the ASTRO-PU is the wrong denominator.
Well, firstly, what is an item? It can be one packet of 21 Dianette, or 6 packets, both of which are common, as are isses of 63 tablets. So it is a long way from the required measurement which would be in tablets, which are of course the DDU for this medication.
Cost, at the other end of the graph, is a good proxy for the total number of tablets. So why put items up there?
A graph of total cost (which stands as a very good proxy for number of Dianette tablets dispensed, versus population, female, 15 to 40 would provide a result to be interested in.
It would also be apparent that this was a graphical presentation of information that actually meant something about what I imagine the prescribing advice department should be trying to show us, and we are all interested in, the difference in what one GP does compared to another.
There remains the phenomenom and problem of regression to the mean which ensures that displays of a large practice have a bias toward appearing average compared to displays from Homefield, and other small practices.
This suggests that a display of data by individual doctor, adjusted for (that age band) list size, would show an even greater divergence.
ASTRO-PU definition and some discussion of how it had been proposed to apply it to some "quality markers".
It is interesting how hard it is to find a definition for ASTROPU, not least because it is abbreviated as ASTRO-PU. It is to be replaced by the STAR-PU but this is a matter of inconsiderable concern to most people.
(ASTRO-PU - the number of prescriptions/head weighted according to geographic and demographic variations)
(DDD - ?Defined Daily Dose? - the assumed average dose per day for a drug used for its main indication in adults)
Found and linked 17 December 2002