WASHINGTON – A diabetes medicine poised to win Food and Drug Administration approval sharply increases the risk of heart problems, strokes and death, researchers reported Thursday in an analysis that raises pointed new questions about the agency’s handling of drug safety issues.

The drug, Pargluva, the first in what had been considered a promising new class of diabetes drugs, more than doubles the risk for life-threatening cardiovascular complications, the researchers concluded after analyzing the studies the drug’s maker presented in its application for approval. Based on the findings, the researchers urged the FDA to withhold approval until additional research can be conducted on the safety questions.

“I do not think it’s wise to approve the drug or see the drug marketed until there’s a dedicated cardiovascular safety trial,” said Steven Nissen of the Cleveland Clinic Foundation, who led the analysis.

“We have to put safety first.”

The Journal of the American Medical Association released the study online Thursday, five weeks ahead of its Nov. 23 publication, because of the public health implications.

The FDA on Tuesday notified the company that the drug was “approvable” pending additional information about the drug’s safety, but it did not specifically request a new study designed to examine the risk of cardiovascular problems.

The critique comes as the agency is struggling to restore its credibility in the wake of a series of embarrassing revelations and controversies, including the withdrawal of the blockbuster painkiller Vioxx last year because of safety concerns, a protracted battle over the Plan B morning-after contraceptive pill, and the sudden resignation of FDA Commissioner Lester Crawford, which remains shrouded in mystery.