Rapidly growing patient lists at the centres skewed the way their prevalence was calculated for 2009/10, and left some with ‘extraordinarily high prevalence’, a GPC document reveals.
Some health centres recorded prevalence of up to 200% for disease domains. All practices in the bottom 5% of the range of prevalence nationally receive the same QOF pay weighting.
Because the outliers were so extreme, many practices with prevalence well above national average will have received the same weighting on points in the worst-hit domains as those with zero prevalence. Vascular domains and the hypothyroid domain are understood to have been heavily hit.
GPC negotiator Dr David Bailey said the problem had caused ‘significant variations’ in QOF pay. High prevalence practices may have lost thousands of pounds, while those with low prevalence gained.
Dr Bailey said Darzi centres may not have benefited financially but ‘are just responsible for the skewing of [QOF prevalence figures]’.
Expanding practices can record abnormally high prevalence because it is calculated by dividing the number of patients on a disease register on 31 March by the practice’s registered population on 1 January.
If a practice list grows rapidly between these dates, prevalence for disease areas can be substantially skewed.
The GPC document explains: ‘A new practice with just 10 patients on 1 January but which has grown by 31 March to include 11 patients with thyroid disease, would have a prevalence of 110%.’
Jon Ford, head of the BMA's health policy and economic research unit, said some practices recorded prevalence of 200% in disease domains. ‘The prevalence was unfeasibly large, which makes a nonsense of it. People will have lost out,’ he said.