Intensive glycaemic control shows ischaemic heart disease benefit

By Lucy Piper, Senior medwireNews Reporter

Intensive glucose lowering may significantly reduce the risk of ischaemic heart disease in at-risk middle-aged people with Type 2 diabetes, a post-hoc analysis of the ACCORD trial suggests.

Among 10,251 study participants, the 5128 treated to achieve a target glycated haemoglobin (HbA1c) level below 42 mmol/mol (6.0%) were 20% less likely to have a fatal or non-fatal myocardial infarction during the average 3.7 years of active treatment than the 5123 treated to achieve a standard HbA1c level of 53 to 63 mmol/mol (7.0–7.9%).

And this reduced risk was maintained over an additional 1.2 years of follow-up after intensive treatment was replaced with standard treatment.

The findings were similar for non-fatal myocardial infarction alone and the composite ischaemic heart disease outcomes of myocardial infarction, unstable angina or coronary revascularisation, and any myocardial infarction or unstable angina, with intensive glucose lowering reducing the risks by 22%, 11% and 21%, respectively.

The researchers, led by Hertzel Gerstein (McMaster University and Hamilton Health Sciences, Ontario, Canada), found that adjusting for the HbA1c concentrations achieved before treatment transition rendered the effects nonsignificant.

This “supports the hypothesis that the degree of glucose lowering or some closely related factor accounts for the effect of the intervention on ischaemic heart disease”, they report in The Lancet.

Together with evidence of raised glucose concentrations and increased cardiovascular risk in people with genetic markers of hyperglycaemia, the findings suggests that “rising glucose concentration is a modifiable risk factor for ischaemic heart disease”, they add.

Although intensive glucose had a beneficial effect on ischaemic heart disease, the researchers note that the results do not negate the ACCORD findings of an increased risk of death from cardiovascular disease with intensive versus standard glucose lowering and are at odds with the observation that intensive glucose lowering did not reduce the risk of fatal myocardial infarction alone.

As most of the deaths occurred in patients whose HbA1c concentrations did not decrease from baseline, the team suggests that persistent but failed attempts to lower glucose concentrations in these individuals may have been harmful.

In a related comment, Jean-Louis Chiasson and Jacques Le Lorier, from the University of Montreal in Quebec, Canada, agree that further assessment of the risks and benefits of intensive glucose-lowering treatment is required.

“In the meantime it is probably wise to aim for a target HbA1c concentration of less than 64 mmol/mol (8.0%) in patients older than 65 years with comorbidities”, they recommend.

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