Why People with Diabetes Should Probably Take a Statin
In a recent commentary, Why People with Diabetes Need to Avoid Statins, David Mendosa makes his case against the use of statins for people with diabetes (PWD). He uses a newly-published study, "Simvastatin impairs exercise training adaptations" as his main argument. I also reviewed the preprint of the study, kindly supplied to me by the lead author. I do agree with one of David's points, which is reiterated by the author of the study, that statins are not for everyone. And yes, they do have side effects, including the rare possibility of devastating muscle damage (called rhabdomyolysis).
But the new study is very small (only 37 participants, and only 18 took a statin), used only one statin (simvastatin), was not double-blinded (so the researchers and participants knew who was on a statin and who wasn't), not even placebo-controlled (the 19 participants not on a statin weren't given a placebo), of too short a duration (only 12 weeks), and the participants weren't even diabetic (they had to be "sedentary overweight or obese adults with at least 2 metabolic syndrome risk factors"). In fact, the presence of diabetes was an exclusion criteria for the study.
That's adequate to qualify as a pilot study, but the findings have no import whatsoever to PWD, especially when compared to numerous other huge studies showing the benefits of statins in people with diabetes.
One of the most persuasive studies was called the Heart Protection Study. This study, which involved 5,963 adults (aged 40-80 years) known to have diabetes (and an additional 14,573 with occlusive arterial disease but not diagnosed as having diabetes), found that wider use of the same statin, simvastatin, would "cut the risk of heart attacks, strokes or revascularisation operations by about a third in diabetic patients, irrespective of their cholesterol levels and whether or not they have existing arterial disease." (And yes, the HPS was a randomized placebo-controlled trial). The authors conclude that "Statin therapy should now be considered routinely for all diabetic patients at sufficiently high risk of major vascular events, irrespective of their initial cholesterol concentrations."
The drug companies also have to provide evidence from persuasive clinical trials to get their statins approved by the FDA. These studies are the basis for claims in the approved labeling (USPI) for each drug.
For simvastatin (Zocor), the label claims include the statements that "In patients at high risk of coronary events because of existing coronary heart disease, diabetes, peripheral vessel disease, history of stroke or other cerebrovascular disease, ZOCOR is indicated to:
Reduce the risk of total mortality by reducing CHD deaths.
Reduce the risk of non-fatal myocardial infarction and stroke.
Reduce the need for coronary and non-coronary revascularization procedures."
For the leading statin, atorvastatin (Lipitor), the label claims are similar: "LIPITOR is an inhibitor of HMG-CoA reductase (statin) indicated as an adjunct therapy to diet to:
Reduce the risk of MI, stroke, revascularization procedures, and angina in patients without CHD, but with multiple risk factors.
Reduce the risk of MI and stroke in patients with type 2 diabetes without CHD, but with multiple risk factors.
Reduce the risk of non-fatal MI, fatal and non-fatal stroke, revascularization procedures, hospitalization for CHF, and angina in patients with CHD."
I have written about statins before: Statins: good drugs for bad cholesterol. I urge the interested reader to read that essay also.
Disclosure: The author was previously employed by Parke-Davis/Pfizer, the manufacturer of Lipitor. He has no present financial interest in the company. He does take a statin (simvastatin) for his hyperlipidemia.