MRSA targets — down to chance?
Chance makes it impossible to assess reliably whether hospitals are meeting Government targets to reduce methicillin-resistant Staphylococcus
aureus (MRSA) infections, according to an article in the BMJ last month
(2005;331:976–77).
David Spiegelhalter, a senior scientist at the Medical Research Council
Biostatistics Unit, Cambridge, warns that setting targets for individual
hospitals, such as the Government’s national target for reducing
the rate of MRSA infection by 50 per cent by 2008, is fraught with difficulties.
He says that the basic problem is that it is unclear whether the targets
refer to an observed rate reduction or a true reduction in underlying
risk. He says that this ambiguity is unimportant at a national level
but, for individual hospitals, chance variation can make observed rates
extremely volatile and make simplistic notions of “hitting targets” unreliable.
According to Mr Spiegelhalter, the Government needs to define the term “target” more
precisely in this context.
Looking at data for financial years 2001-04, he found far more variability
in the figures than would be expected by chance alone. He explained that
this could be due to the fact that MRSA is infectious and therefore tends
to occur in clusters.
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Hospital Pharmacist