Monday, 22 March 2010

Intensive blood pressure control in diabetes 'has no benefit'

Intensive blood pressure control in diabetes 'has no benefit'

Intensive controlling the blood pressure of patients with type 2 diabetes is not beneficial – even in patients at high risk of cardiovascular disease according to data from the latest analysis of the pivotal ACCORD study.

A subset of the trial included 5,000 patients with type 2 diabetes treated to a systolic target of either below 120 or 140 mm Hg. After one year, the mean systolic blood pressure was 119.3 mm Hg in the intensive group and 133.5 mm Hg in the standard therapy group.

But researchers found no significant difference between intensive and standard control of blood pressure in the overall annual rate of non-fatal heart attacks and strokes or deaths from cardiovascular disease. Although intensive blood pressure control did significantly reduce the annual rate of stroke it was associated with a more than doubling in adverse events.

After a mean follow-up period of 4.7 years the annual rate of the primary outcome – the composite incidence of non-fatal heart attacks, non-fatal strokes and death from cardiovascular causes – was 1.9% in the intensive therapy group and 2.1% in the standard therapy group. The hazard ratios showed intensive therapy increased the risk of the primary outcome by 12%, though this was not statistically significant.

The annual rates of death from any cause were 1.3% and 1.2% in the intensive and standard groups respectively, while the annual rates of strokes, a pre-specified secondary outcome, were 0.3% and 0.5% respectively.

Intensive antihypertensive treatment resulted in significantly more serious adverse events, reported by 3.3% of the intensive group compared to 1.3% of the standard treatment group, mostly hypotension, hypokalaemkia and increases in serum creatinine.

Lead researcher Dr William Cushman, professor of preventive medicine at the University of Tenneesee, concluded: ‘It is possible that lowering systolic blood pressure from the mid-130s to approximately 120 mm Hg does not further reduce most cardiovascular events or the rate of death, and most of the benefit from lowering blood pressure is achieved by targeting a goal of less than 140 mm Hg.’

In an accompanying editorial, Dr Peter Nilsson, a cardiologist at the University Hospital Malmö in Sweden said: ‘The main conclusion to draw from this study must be that a systolic blood-pressure target below 120 mm Hg in patients with type 2 diabetes is not justified by the evidence.

‘Flexible goals should probably be applied to the control of hyperglycaemia, blood pressure, and dyslipidaemia in patients with type 2 diabetes, taking into account individual clinical factors of importance.

Dr Richard Lehman, a GP in Banbury, Oxfordshire with an interest in cardiology, said: ‘This confirms that we have to go by hard endpoints. You can’t assume that by treating everybody to a lower and lower target you will get benefit, because you don’t. You actually mess up people’s lives but for very little reward.’

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