Heart doctors spar over diabetes drug

CHICAGO (CNNMoney.com) -- Debate over the heart attack risk associated with the GlaxoSmithKline diabetes drug Avandia took center stage Monday at the annual meeting of the American Diabetes Association.

Cleveland Clinic chief cardiologist Dr. Steve Nissen defended his "meta-analysis," published in May in The New England Journal of Medicine, concluding that use of Avandia appears to significantly increase the risk of heart attacks, a finding Glaxo (Charts) refutes.

Nissen collated data from 46 Avandia studies, including those conducted by Glaxo, to arrive at the conclusion.

"When you see this kind of consistency in data, it makes you believe that something real is going on," said Dr. Nissen, who began noticing what appeared to be cardiovascular risk as early as 1999, when Avandia was being reviewed by the Food and Drug Administration.

But Dr. Philip Home, a professor of diabetes at Newcastle University in the United Kingdom and a member of the steering committee for one of the Avandia studies included in Nissen's analysis, criticized the way Nissen conducted his analysis.

"I think this is data snooping on quite a big scale," said Dr. Home, attacking Dr. Nissen for seeking out data points in pre-existing studies rather than launching a separate study to test a hypothesis. Dr. Home also said he found conflicting results in a study conducted by Dr. Nissen's own Cleveland Clinic.

But Dr. Nissen said it was his duty to publish his results for the benefit of the medical community, noting that he has not asked for Avandia's withdrawal from the market. He also said his meta-analysis is the best available source of information about Avandia and heart attack risks.

"We want you and others who treat these patients to be aware of the findings," said Dr. Nissen, addressing thousands of cardiologists at a lecture hall in the McCormick Convention Center. "The alternative would be to keep the scientific community in the dark."

Avandia is a member of the same TZD drug class as Actos, though Actos maker Takeda (Charts) has sought to distinguish its drug as bereft on any heart attack risks.

Takeda spokeswoman Jocelyn Gerst reiterated to CNNMoney.com on Monday that Actos does not share the heart attack risks that have been associated with Avandia.