How worrisome is the statin-diabetes link?

The FDA's cautionary word on statin use has stirred up a back-and-forth risk-benefits debate. When the agency announced last week that it would highlight the risk of Type 2 diabetes on the cholesterol drugs' labels, some prominent heart doctors issued their own warnings: Don't worry too much about that risk. For most patients, the heart benefits of statins outweigh the "small" risk of developing diabetes.

But another prominent heart doctor says the diabetes risk should be taken seriously, and wrote a New York Times op-ed to state his case. Dr. Eric Topol contends that the risk is actually greater than the FDA's analysis found, because the agency included studies of lower-powered statin drugs that found no diabetes risk. If only the "more potent statins" such as Zocor, Lipitor and Crestor are in the mix, data show "a consistent excess of diabetes," and the risk increased at higher doses.

To Topol's mind, that diabetes risk is not counterbalanced by cardiovascular benefits, at least not in patients who don't already have heart disease. If we could identify the patients who would benefit from preventive use of a statin, that would be one thing, but that prospect hasn't been studied as it should, Topol says.

Other experts fired back: Dr. Sanjay Kaul told Forbes that the majority of diabetes cases in one statin study arose in people whose blood sugar was elevated to begin with, and those people proved likely to benefit from statins. Pfizer's ($PFE) former R&D chief John LaMattina wrote that there's no way of determining whether the increase in diabetes among statin users might be more accurately attributed to, say, poor dietary choices and lack of exercise; only prospective studies can pinpoint that. And besides, at least one study of Lipitor in diabetics found that cardiovascular outcomes were definitely better in statin patients than in placebo patients, he said.

The arguments delve into study stats and mathematical interpretations, so the details are worth digging into. Plus, Topol has responded to Kaul's comments in Forbes already. No doubt the debate will continue.

- see the NYT op-ed
- read the Forbes article
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