Raleigh, N.C. ? A major national diabetes study was halted Wednesday after researchers found that cutting blood sugar levels to near normal levels in certain patients actually increased the risk of death.

The findings raise questions about the best way to manage patients with the disease.

“The thought was maybe what you need to do is get even tighter with blood sugar and get these patients as close to normal as you can get – conventional wisdom isn’t always right,” said Dr. Mark Feinglos, chief of endocrinology at Duke University Medical Center and an investigator in the study. Duke is among the largest recruitment sites in the state with 174 patients enrolled in the trial.

About 18 million Americans have diabetes. Type 2 accounts for about 90 percent of cases, and cardiovascular disease is a one of the most common complications of the disease. The Action to Control Cardiovascular Risk in Diabetes, or ACCORD trial, sought to reduce heart disease risk in patients at the greatest risk of it.

The federal government said Wednesday it would stop one part of the large trial, which involves 10,251 patients with advanced diabetes. Data showed that Type 2 diabetes patients who had had an intensive therapy of pills and insulin to reduce blood sugar levels were more likely to die than patients on standard therapy. Several smaller studies had suggested that reducing blood sugar to near normal levels cut the risk of death.

Study leaders said Wednesday that 257 patients receiving aggressive treatment to cut blood sugar have died, compared with 203 deaths among patients in a control group. There were about 14 deaths per 1,000 patients in the intensive group, compared with 11 deaths per 1,000 patients in the standard therapy group. Deaths do not appear linked to any of the study drugs.