Intensive cardiovascular risk management in diabetes ‘has no effect’
Intensively managing risk factors in patients newly diagnosed with diabetes in primary care does not have any significant effect on their cardiovascular outcomes compared with usual care, concludes a UK study.
The study found patients treated to tough HbA1c, cholesterol and blood pressure targets did not have significantly different risks of cardiovascular events after five years compared with those receiving standard diabetes care from GP practices.
The study provides further evidence to undermine moves to intensify diabetes treatment early on and provides evidence that standard GP care may be sufficient to prevent an increase in cardiovascular risk.
NICE raised the QOF HbA1c target in 2010 for patients with type 2 diabetes from 7.5% (58mmol/mol) to 7% (53mmol/mol), conceding that there was sufficient ‘uncertainty' about patient safety to justify the move.
An analysis published in June also found aggressively lowering blood glucose in patients with type 2 diabetes only slightly reduces the risk of developing neuropathy, but greatly increased the risk of hypoglycaemia.
This study finds that aggressive management to keep HbA1c levels below 7% (53mmol/mol), blood pressure below 135/85 mmHg, cholesterol below 5mmol/l and prescribing aspirin to those treated with antihypertensive medication did not significantly reduce their likelihood of having a cardiovascular event.
The research involved 379 general practices in Denmark, the Netherlands and the cities of Cambridge and Leicester, with each practice randomised to provide routine care after screening patients for diabetes or intensive multifactorial treatment. Over 3,000 patients without a history of ischaemic heart disease were included in the final analysis, all aged between 40 and 69 years.
Routine care consisted of a standard pattern of diabetes care according to current recommendations applicable in each centre. All patients with a cholesterol level over 3.5mmol/l were prescribed a statin.
Over five years, researchers found non-significant reductions in risk of 17% for a first cardiovascular event from diagnosis when comparing intensive treatment to routine care, and 30% for a second cardiovascular event.
When restricting cardiovascular events to include mortality, non-fatal myocardial infarction and non-fatal stroke, the risk reduction was only 14% when comparing the two groups.
The study authors concluded: ‘Early intensive multifactorial treatment was not associated with a significant reduction in total cardiovascular burden at five years.
‘It remains to be seen whether intensification of early treatment in screen-detected individuals might translate into improved outcomes in the longer term.'
Professor Mike Kirby, a GP in Radlett who participated in the study, said the results show that most practices were taking the right approach with their patients.
He said: ‘The standard of care was already good in most of the control practices, and this makes it difficult to show a difference.
‘The use of statins, good blood pressure control and prescription of metformin made the difference, in my opinion.'
But Dr Roger Gadsby, a GP in Nuneaton and member of the NICE type 2 diabetes guideline development group, said the study follow-up period was too short to show positive outcomes.
He said: ‘In some intervention studies it can take up to 10 years for benefits to be demonstrated and so this negative result might just reflect the five years of the study.
‘There is evidence early intensive glycaemic control improves cardiovascular outcomes in the long term, but they were looking at 10-plus years of follow-up after the intervention.'
Risk reductions for cardiovascular events comparing intensive treatment with routine care
First event – 17%
Second event – 30%
Any event – 23%
Diabetic Medicine 2012, online 23 July