Diabetes control tied to heart stent outcomes

For people with type 2 diabetes, maintaining good blood sugar control in the years after receiving a coronary artery stent is associated with a lower risk of heart attack and stroke, according to a recent study.

“Although intensive glucose control had no benefit on the rate of major cardiovascular events in previous studies, our data suggest that strict glucose control after PCI (heart catheterization) can improve long-term clinical outcomes in diabetic patients,” Dr. Joo-Yong Hahn from Samsung Medical Center in Seoul told Reuters Health.

Heart disease is the major cause of death among people with type 2 diabetes, Hahn’s team writes in Circulation: Cardiovascular Interventions. Although intensive blood sugar control is known to reduce damage to tiny blood vessels that are involved in many of the nerve and circulatory effects of diabetes, it’s not clear if the same is true for major arteries such as the ones that carry blood to the heart.

The researchers studied 980 patients with type 2 diabetes who had undergone percutaneous cardiac intervention (PCI) to clear a blocked coronary artery and place a supportive mesh tube known as a stent. Hahn’s team followed the patients’ health for up to seven years.

They looked at long-term blood sugar control using a measurement known as hemoglobin A1c (HbA1c or A1C), and used it to compare the patients’ risks of death, heart attack, repeat catheterizations and stroke over the study period.

The researchers defined good control as an A1C score below 7.0 and poor control as A1C of 7.0 or higher. Then they matched patients according to other risk factors and ended up with 322 pairs of patients for comparison.

In the overall group of 980 patients, the risk of all bad outcomes was 25 percent lower with good blood glucose control than with poor blood glucose control.

In the matched comparison, some 37 percent of patients with poor control had bad outcomes (heart attack, stroke, and so on) over the next seven years, versus less than 28 percent of patients with good control. Most of the difference in bad outcomes between the groups resulted from a higher rate of repeat stenting in the group with poor blood glucose control.

“PCI is not the end of treatment for coronary artery disease,” Hahn said by email. “Optimal medical treatment, including glycemic control, is a cornerstone therapy after PCI,” he said.

“The effects of glucose control in type 2 diabetes may differ according to patient characteristics, such as recent cardiovascular events, baseline glycemic control status and duration of diabetes,” Hahn added.

The researchers write that more study is needed before they can conclude strict glucose control after stenting will improve long-term clinical outcomes in people with diabetes.

It’s important to underscore the message of good glycemic control, said Dr. Azfar G. Zaman from Newcastle University in the UK. He was not involved in the study but has done similar research. “In patients with PCI there is evidence to support better outcomes and need for fewer interventions,” Zaman said by email.

“This is a single center study with limited numbers, but the findings support data from other studies,” he noted.