Changes in the prevalence formula will triple the gap in QOF funding between practices in London and those in the north of England, GP newspaper can reveal.
London's lower recorded disease prevalence means that average practices in the city are paid less per QOF point than those in any other part of the country.
Figures from specialist medical accountants Ramsay Brown and Partners show that at present, a 5,000-patient practice of average prevalence in London receives around £108,000 for achieving 1,000 QOF points. This is £19,000 less than an average practice in the North East.
But over the next two years the statistical tricks used to even out the variation in QOF funding will be removed from the formula, as practices move to raw prevalence.
This means that, in 2010/11, the value of 1,000 QOF points to London's average practice will fall to just £94,000. In the North East, by contrast, the changes will boost average QOF income to £148,000 - a gap of £54,000.
Elaine Gill, the accountant who compiled the figures, said she had been surprised by the way prevalence factors varied nationwide. 'We were expecting a more obvious split between inner and outer London PCTs - but actually the variation is more regional,' she said.
'It's a bit silly to say that London practices have an easier workload than everyone else,' she added. 'They have been suffering in the past - this change will hit them doubly hard.'
Experts suggested that London's more transient population may make it harder for practices to collect the data they need to accurately assess prevalence.
Others said that many things that take up London GPs' time were not reflected in the current prevalence formula, citing the greater extent of mental health problems and drug use, and the number of patients who speak English as a second language.
GPC negotiator Dr Chaand Nagpaul said that the shift to raw prevalence was intended to better reflect practice workloads, and so would inevitably make funding differences more marked.
But he added: 'London does have its own set of challenges for GPs, not covered by the QOF.
'What is important is that the money liberated from lower prevalence in London should be reinvested in other practices in London in areas that are being ignored,' he said.
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