Questions raised over 'GP bonus system'
The GP bonus system has been called into question after research suggests it has had no real impact on the treatment of high blood pressure.
Family doctors are paid bonuses - worth up to a third of their pay - for hitting certain performance targets.
An international team of experts looked at high blood pressure measures, but found "no discernible" benefit, the British Medical Journal reported.
Doctors said it was too early to judge the scheme.
The bonus system was introduced in 2004 as part of a new contract. It has proved controversial as it has helped push average pay through the £100,000 barrier.
The researchers from the US and Canada as well as the UK's Nottingham University, looked at rates of blood pressure monitoring, control and treatment alongside how many patients ended up getting ill.
They analysed records from nearly 500,000 patients from before and after the introduction of the bonus system, known as the Quality and Outcomes Framework.
This revealed there was little improvement that could be attributed to the bonus system, although there did seem to be a small improvement in the numbers getting treated.
The incidence of problems such as strokes and heart attacks did not improve either.
Professor Stephen Soumerai, one of the researchers, said: "The programme's lack of effect may be explained in part by performance targets that were set too close to existing practice."
The researchers did not look at other parts of the bonus system, but concerns about whether the targets were ambitious enough have been voiced before as doctors hit an overwhelming number of them.
Dr Laurence Buckman, of the British Medical Association, pointed out the targets did change to respond to new evidence and he suggested it was too early to fully judge the merits of the system.
"It is still relatively new. Other studies have shown that it has improved care and treatment for people with diabetes and reduced the number of heart attacks and deaths, particularly in deprived areas. We expect the true gains will be seen in the long-term as more evidence becomes available."
A Department of Health spokesperson said: "The Quality and Outcomes Framework and other incentives for GPs are insufficiently focused on outcomes, including patient experience.
"We therefore intend to reform the current payment system so that GPs are rewarded appropriately for improving patient outcomes.
"High levels of exception reporting for outcomes can undermine the overall accountability for performance. So, we will look closely at exception reporting and prevalence recording patterns as part of that process."