Tight Glycemic Control Won't Cut Diabetes Patients' Heart Failure Risk

Dr. John J. V. McMurray from BHF Glasgow Cardiovascular Research Center in the UK and the lead researcher said the findings "add to recent evidence of lack of macrovascular benefit (heart attacks, strokes, and now heart failure) of more intensive glycemic control." "And it's important to remember "that better glycemic control does seem to reduce the risk of microvascular complications," such as diabetic eye disease, nephropathy and neuropathy.

The meta-analysis by Dr. McMurray and colleagues failed to show a benefit of tight glycemic control on heart failure risk reduction. The analysis included eight studies that compared a more intensive glucose-lowering regimen to a standard one in 37,229 type 2 diabetics followed for two to 20 years. Overall there were 1,469 heart failure-related events -- with more than half (55%) occurring in the intensive treatment arm.

The average difference in glycated hemoglobin level between patients given standard treatment and those allocated to a more intensive regimen was 0.9%, according to the report.

In the pooled analysis, intensive glucose control did not influence the overall occurrence of heart failure-related events, with a nonsignificant 20% increase in risk compared to conventional regimens (odds ratio 1.20). However, the "the effect estimate was highly heterogeneous, with almost 70% of variability across studies attributable to heterogeneity rather than chance," the authors wrote.

In a subgroup analysis, the odds ratio for heart failure-related events was 1.33 when intensive glycemic control was achieved using a thiazolidinedione.

There are several possible reasons why intensive glucose control does not lead to the reduction in risk of heart failure "predicted by epidemiological studies," the authors note.

They say their results may reflect "insufficient duration of treatment or follow-up, treatment intervention too late in the course of the disease, off-target toxicity of the treatments used, or because hyperglycemia per se does not directly cause heart failure in diabetic patients (i.e., is a marker rather than mediator)."

Am Heart J Oct. 10, 2011 published online