The risk-benefit ratio for Actos (pioglitazone) in the treatment of type 2 diabetes is unclear, according to a review of clinical trials reported in the the October 18th online issue of The Cochrane Library.

Actos belongs to a class of drugs called thiazolidinediones that work by increasing the body's sensitivity to insulin, to better control patients' blood sugar. It is used alone or in combination with other drugs if diabetes can't be controlled by diet and exercise.

Lead researcher Dr. Bernd Richter, from Heinrich-Heine University in Dusseldorf, Germany, said that after evaluating published studies in which patients with type 2 diabetes were treated with pioglitazone, the researchers found no "convincing evidence" that Actos reduced mortality, morbidity or adverse effects, or positively influenced health-related quality of life.

Results from the United Kingdom Prospective Diabetes Study (UKPDS) and the University Group Diabetes Program (UGDP), the two biggest type 2 diabetes trials, also failed to show that the adverse effectsof cardiovascular disease were lessened by improved metabolic control in diabetics, he said.

BecauseIit was unclear if newer drugs, such as Actos, have a beneficial effect, Richter's team identified clinical trials of 24 weeks' duration or longer that evaluated Actos as a treatment for type 2 diabetes in their effort to determine if newer drugs like Actos have a beneficial effect.

Twenty-two trials were identified, which included roughly 6,200 people with type 2 diabetes. The longest duration of use of Actos was just under three years.

Not only did researchers find little evidence that treatment with Actos improved patient outcomes; they found the drug did not seem to provide superior metabolic control compared with other oral antidiabetic agents and said it was more commonly associated with fluid retention than were other drugs.

"Pioglitazone treatment should be restricted to patients demonstrating real benefit of this therapy," Richter concluded.