Prescribing savings in 2008
The National Audit Office report Prescribing costs in primary
care, published in May 2007, was accompanied by a table setting out
potential savings that Primary Care Trusts (PCTs) could achieve,
without affecting patient outcomes, through a more consistent use
of generic medicines in four therapeutic areas. The NAO report and
accompanying materials, including guidance material for Prescribing
Advisers, is available at
http://www.nao.org.uk/publications/0607/prescribing_costs_in_primary_c.aspx.
At the end of 2008 we commissioned the Department of Medicines
Management at Keele University to calculate the actual savings that
PCTs had achieved. The savings are calculated by comparing each
PCT’s actual expenditure, in the four therapeutic areas considered,
with what the PCT would have spent, if the relative proportions of
different medicine formulations prescribed in the 12 month period
August 2005 to July 2006 (the benchmark for the NAO report) had
remained the same during 2008. It should be noted that the
magnitude of the savings achieved by each PCT is likely to be a
reflection of the PCT’s baseline prescribing position. More details
on how the calculations were carried out are given overleaf. The
methodology we have used assesses savings on the basis of actual
expenditure at prevailing Drug Tariff prices.
The savings calculated therefore represent savings that
have been obtained through changing prescribing patterns, rather
than changing prices for medicines, over the time period
considered.
The total saving in 2008, across all PCTs in England, was £394
million. The tables
attached (in an Excel Spreadsheet) show how this figure
breaks down by PCT.
How the savings have been calculated
For statins, proton pump inhibitors (PPIs), and renin
angiotensin drugs (ACE and ARB):
- The data has been analysed at presentation level, so that it
includes every single formulation of each drug, in the above
therapeutic areas, dispensed by each PCT for each month in 2008,
and for the 12 month period August 2005 to July 2006.
- From this data the total number of defined daily doses (DDDs)
dispensed for each therapeutic area in 2005-06 was calculated, and
the relative proportion of DDDs accounted for by each individual
formulation of each drug was determined.
- These relative proportions were used to predict the numbers of
DDDs of each formulation that would have been dispensed in 2008,
had the 2005-06 proportions been maintained.
- The predicted number of DDDs for each formulation was then
multiplied by the cost per DDD for that formulation for each month,
thus incorporating any price changes occurring in 2008, to give a
predicted spend.
- The actual spend was then subtracted from the predicted spend
to give a savings figure.
For clopidogrel:
- From the presentation-level data, the number of DDDs dispensed
per specific therapeutic area age-sex related prescribing unit
(STAR PU) in 2005-06 was calculated for each PCT.
- The predicted spend for 2008 was obtained by using the 2005-06
DDD/STAR PU figure to predict the number of DDDs based on 2008 STAR
PUs, and multiplying this by the cost per DDD.
- The actual spend was then subtracted from the predicted spend
to give a savings figure.
For more details on definitions, including a discussion of DDDs,
STAR PUs, and prescribing efficiency metrics, please see the
Technical
Supplement to the 2007 National Audit Office report
Prescribing costs in primary care.