The controversies of statin therapy: weighing the evidence.

The debate whether statins, 3-hydroxymethyl-3-methylglutaryl coenzyme A reductase inhibitors, are safe to use has been raging since their introduction in 1987. Statins are generally well tolerated and are believed to have minimal adverse effects. However, individual, specific rare adverse events have been reported, such as elevations of liver enzymes, muscle aches, and very rarely, rhabdomyolysis. Discontinuation and/or reduction in the dose of the statin usually leads to resolution of these side effects. Recently, however, debate has focused on the possible negative long-term effects of statin treatment on cognitive decline, the incidence of cancer, and the development of diabetes mellitus. Recently, the U.S. Food and Drug Administration has expanded the warning for statins with a statement that statin use may lead to cognitive impairment. In this review, we discuss all levels of evidence, from case reports to large randomized controlled clinical trials, for the possible adverse effects of statins on cognitive decline, cancer, and diabetes. After careful consideration of all discussed scientific evidence, we conclude that there is no increased risk of cognitive decline or cancer with statin use. However, statin use is related to a small increased risk of type 2 diabetes mellitus. In view of the overwhelming benefit of statins in the reduction of cardiovascular events, we believe the small absolute risk for development of diabetes is outweighed by the cardiovascular benefits in patients for whom statin therapy is recommended. We, therefore, suggest that clinical practice for statin therapy should not be changed on the basis of the most recent Food and Drug Administration informational warnings.