The results of the ACCORD trial, which was designed to determine whether treating diabetes would reduce heart disease, found that no particular drug was responsible for serious cardiovascular problems. This would appear to contradict the controversial meta-analysis published last spring in the New England Journal of Medicine, which contended Avandia increased the risk of heart attacks and strokes by 43 percent.

But the National Heart, Lung and Blood Institute, which funded and helped organize the trial, says the culprit behind heart attacks and strokes appeared to be a strict lowering of blood sugar, or glucose. The agency says the trial will be adjusted so patient blood sugar levels wouldn’t be lowered so intensively.

“We found no link,” William Friedewald of Columbia University in New York, one of the directors of the trial, says in a statement. “Extensive analyses by ACCORD researchers have not determined a specific cause for the increased deaths among the intensive treatment group. Based on analyses conducted to date, there is no evidence that any medication or combination of medications is responsible,” adds the NHLBI, which did its own analysis.

“In this trial of adults with type 2 diabetes at especially high risk for heart attack and stroke, the medical strategy to intensively lower blood glucose (sugar) below current recommendations increased the risk of death compared with a less-intensive standard treatment strategy,” the NHLBI says.

More than 10,250 people participated in the study. Of these, 257 in the intensive treatment group died, compared with 203 within the standard treatment group. This is a difference of 54 deaths, or 3 per 1,000 participants each year, over an average of almost four years of treatment, the NHLBI explains. However, “the death rates in both groups were lower than seen in similar populations in other studies,” the statement read.

Glaxo says the findings appear to raise questions about how aggressively blood sugar should be reduced in managing diabetes. “The same drugs are used in both groups of patients who are either managed aggressively or to standard blood sugar control, yet the small increase of events is seen in the group who are aggressively managed,” the drugmaker says in a statement.