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Do Statins Cause Diabetes?

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Updated October 21, 2013

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

You may have read reports in the press that statin drugs have been linked to the development of type II diabetes. Do statin drugs really make diabetes more likely? And if they do, is the increased risk anything to worry about?

These questions seem particularly important in view of the fact that, recently, FDA-approved indications for using statin drugs have been greatly expanded. Statins are now recommended not only in people with elevated cholesterol levels whether or not they have known heart disease, but also in certain people who don't even have an elevation in cholesterol levels. This broadened usage of statin drugs is based on well-conducted, randomized clinical trials showing that, when used in the right people, statins can produce a significant reduction in heart attacks, strokes, and the need for coronary artery revascularization procedures (i.e., stents or bypass surgery).

One potentially disturbing "signal" that has been seen in some of these clinical trials, however, is the finding that patients randomized to statin drugs may have had a higher risk of developing type II diabetes. In particular, this finding was noted in the well-known JUPITER trial, the landmark trial that led the FDA to approve the statin drug Crestor for patients with elevated CRP levels.

Studies Looking Specifically At Statins and Diabetes

Two major studies have now specifically addressed the question of whether statins lead to an increase in diabetes. The first, published in the Journal of the American Medical Association in June, 2011, was a meta-analysis of 33,000 patients enrolled in five major clinical trials using statins. This meta-analysis concluded that the use of high-dose statins was associated with one additional case of type II diabetes for every 498 patients treated; whereas one major cardiovascular event (such as heart attacks and strokes) was prevented for every 155 patients treated. The authors concluded that, while statins do indeed appear to increase the risk of type II diabetes, when they are used in people with a high risk for cardiovascular disease, the benefit of statins appears to substantially outweigh the risk.

The second study, published in January, 2012 in the Archives of Internal Medicine, analyzed data from 153,840 postmenopausal women between 50 and 80 years of age who were enrolled in the Womens Health Initiative study. In this observational study, women taking statins had a 48% increased risk of diabetes compared to women not taking statins.

What Can We Conclude From This Information?

There is enough evidence now from enough clinical trials to conclude that statins, at least at high-dose, are associated with a significantly increased risk of developing type II diabetes. Whether the risk of diabetes with statins is substantially higher in postmenopausal women than in other groups is certainly possible, but as yet is unproven.

Despite the risk of diabetes, however, in people who are at high risk for heart attacks and strokes, the use of statins significantly reduces the overall risk of having serious cardiovascular events.

So experts agree that in high-risk people - especially those who already have known cardiovascular disease - the use of statins remains an extremely important part of reducing subsequent risk.

There is more controversy, however, in using high-dose statins in people who do not yet have cardiovascular disease, but are moderate risk of developing it. It is likely that prospective clinical trials will need to be done in such individuals to really define the optimal role of statins.

Recommendations

If you have coronary artery disease or have had a stroke, or if your cardiac risk factors place you in a high-risk category, your doctor will want you to take a statin. This is because - even with an increase in the risk of diabetes - a statin drug will significantly reduce your overall risk of death or of having another serious cardiovascular event.

If you are at moderate risk for cardiovascular disease, a statin still may turn out to be a good idea - but only after you carefully discuss with your doctor the relative risks and benefits of statin therapy, as well as possible alternative method of reducing your risk. For instance, if you are able to engage in an aggressive program of lifestyle changes, you might very well move yourself into a low-risk category without the use of statins.

Sources:

Preiss D, Seshasai SR, Welsh P, et al. Risk of incident diabetes with intensive-dose compared with moderate-dose statin therapy. JAMA 2011; 305:2556-2564.

Culver AL, Ockene IS, Balasubramanian R, et al. Statin use and risk of diabetes mellitus in postmenopausal women in the Women's Health Initiative. Arch Intern Med 2012; DOI: 10.1001/archinternmed.2011.625.

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