Targets set for GPs to improve the care of patients with high blood pressure have had no impact, according to a new study published on bmj.com.

Researchers found that nationally set targets in the UK, that have financial rewards for GPs if they are met, have made no discernible difference to improving care and outcomes for patients with hypertension (high blood pressure).

Around half of people aged over 50 have hypertension, which is one of the most treatable, but undertreated cardiovascular risk factors.

The Quality and Outcomes Framework (QOF) for general practice is a voluntary system of financial incentives, which has been in place since 2004 and part of this programme includes specific targets for GPs to demonstrate high quality care for patients with hypertension and other diseases.

The UK National Health Service committed £1.8bn (€2.1bn; $2.8bn) in funding to the programme. Yet, to date, there is little evidence of the effectiveness of pay for performance targets.

A team of international researchers from the UK, USA, and Canada set out to assess the impact of the targets on quality of care and outcomes among UK patients with hypertension.

They studied data from The Health Improvement Network (THIN), a large database of primary care records from 358 UK general practices.

They found there were 470,725 patients diagnosed with hypertension between January 2000 and August 2007.

They looked at various measures including blood pressures over time; rates of blood pressure monitoring, blood pressure control and treatment intensity at monthly intervals three years before and four years after the introduction of the targets; and hypertension outcomes as well as illnesses.

Analysis showed that even after allowing for secular trends, there was no change in blood pressure monitoring, blood pressure control, or treatment intensity that could be attributed to the QOF targets.

There was a decline in the proportion of patients receiving no medicines or only a single medicine, at the same time as a rise in numbers of patients receiving combination therapy with two or three plus medications.

The researchers found, however, that the QOF targets were not associated with any change to these trends in medication prescribing.

Similarly, there was no identifiable impact from the targets on the cumulative incidence of stroke, heart attacks, renal failure, heart failure or mortality in both patients who had started treatment before 2001 and another sub-group of patients whose treatment had started close to the first QOF interventions.

The quality of care for hypertension, such as blood pressure monitoring and treatment intensification, was already improving before the QOF began, said the researchers.

They conclude: "The programme's lack of effect may be explained in part by performance targets that were set too close to existing practice. To stimulate further improvement in hypertension care in the UK, it may be necessary to implement other evidence based interventions on a large scale."

Two linked analysis articles look at what measures of preventing cardiovascular disease are the most efficient and cost effective, while an editorial suggests that the current model in the UK is not necessarily the right one or the only one.