People with diabetes are always exhorted to keep their blood sugar levels under control, but in some cases the advice might not be appropriate.

Contrary to what has been shown in otherwise healthy diabetics, elevated hemoglobin A1c levels - an indicator of poor glucose control - are associated with improved survival among diabetics with advanced heart failure, new research shows.

“The presumption was that better glycemic control would be associated with better outcomes” senior author Dr. Gregg C. Fonarow, from the University of California at Los Angeles, told Reuters Health.

“Yet, in previous studies, a number of factors normally tied to adverse outcomes, such as High cholesterol levels, have been linked to improved outcomes in patients with heart failure.” So, it was unclear what to expect with elevated hemoglobin A1c levels, he added.

In the study, reported in the American Heart Journal, the outcomes of 49 diabetics with A1c levels no greater than 7 were compared with those of 74 patients with higher levels. All of the patients had advanced heart failure.

“The American Diabetes Association recommends a target hemoglobin A1c of 7.0 or lower, which is why we used this” cutoff, Fonarow explained.

The researchers found that poor glucose control was associated with an all-cause mortality of 20 percent during 2 years of follow-up, significantly lower than the 35 percent rate seen in patients with recommended levels of blood sugar control.

“This study alone should not change the diabetes management of patients with heart failure, but hopefully it will spur further research in this patient population,” Fonarow said.

SOURCE: American Heart Journal, January 2006.