Tight control of diabetic patients’ blood glucose levels often helps prevent them from developing complications, such as kidney disease and nerve damage. But for patients who have advanced heart failure and diabetes, significantly decreasing their glucose levels might raise their mortality risk, a study says.

Diabetic patients with heart failure who had lower levels of glycosylated hemoglobin were more likely to die or need urgent heart transplantation during two years of follow-up compared with those with higher HbA1c levels, according to the study published online March 29 in The American Journal of Cardiology.

One possible explanation for the finding is that patients with lower HbA1c levels might be taking an inappropriate medication to control their diabetes, such as insulin, said senior study author Tamara B. Horwich, MD. Though insulin might decrease glucose levels, it often is linked to poor health prognosis for people with heart failure, she said.

“We may find that doctors who treat patients who have advanced heart failure and diabetes may not need to focus on aggressively lowering blood [glucose], but rather keep it under moderate control,” said Dr. Horwich, assistant professor of cardiology at David Geffen School of Medicine at UCLA.

About 6 million people in the United States have heart failure, and about one in five dies within a year of being diagnosed with the condition, according to the Centers for Disease Control and Prevention.

An estimated 25% of those with heart failure also have diabetes, according to The American Journal of Cardiology study.

Researchers examined the medical records of 845 patients 18 and older who had advanced heart failure and received treatment at the Ahmanson-UCLA Cardiomyopathy Center between Jan. 1, 1999, and July 1, 2010.

Researchers found that of the studied patients, 358 (42%) had diabetes. The HbA1c levels of those with the chronic condition ranged from 4.5% to 14.3%. The American Diabetes Assn. recommends that people with diabetes keep their levels at 7% or lower to help prevent serious complications.

But in the study, event-free survival after two-years of follow-up was more common among heart failure patients with diabetes who had the highest HbA1c levels (65% survival) than those with the lowest levels (48%).

Researchers said the ideal HbA1c level for that patient population seems to be between 8.3% and 8.9%. But they said more research needs to be conducted to verify that range and to assess the best anti-diabetes medications for patients who also have advanced heart failure.

The full and original article can be found at: http://www.ama-assn.org/amednews/2012/04/23/hlsc0425.htm