According to the latest research taking a high-dose statin to lower cholesterol may increase risk of developing diabetes by as much as 12 percent, but the heart benefits of statins still outweigh the risks.
Statins such as Pfizer's Lipitor are the world's best-selling drugs and they work by lowering levels of low-density lipoprotein, or LDL, the so-called “bad” cholesterol. This new study that was published on Tuesday comes with a warning that it should not prompt any patients to stop taking statins, but patients on high doses of statins should get screened regularly for diabetes.
The findings on two of the biggest-selling statins may lead doctors to choose Lipitor when high doses are needed versus the less expensive, generic version of Merck & Co's Zocor. Results showed that both drugs raise the risk of diabetes, high-dose Lipitor worked far better than generic Zocor at cutting heart risks, the team said.
The team from St George's, University of London and the University of Glasgow analyzed data from five different studies involving 32,752 patients who were treated with high and moderate doses of statins. Over a five-year period, 2,749 participants, or 8.4 percent, developed diabetes, and 6,684 participants, or 20 percent, had a major heart problem.
Professor Kausik Ray of St George's said, “Overall, we found that high doses were associated with a 12 percent increased risk of diabetes compared with standard doses.” He said for every 498 patients treated there was one extra case of diabetes. But use of high-dose statins reduced risk of heart attacks, strokes, and the need for artery-clearing angioplasty by 16 percent. For every 155 people treated, one of these heart problems was prevented, the team reported in the Journal of the American Medical Association.
Professor Peter Weissberg of the British Heart Foundation, who was not involved with the study, said in a statement, “Nobody should stop taking their prescribed statins because of the evidence shown in this research. Statins play a vital role in protecting the hearts of many, many people and the benefits still far outweigh any risks associated with diabetes.”
Ray explained, “Patients who need high doses of statins are at very high risk of heart attacks and strokes. They should not come off these drugs, but simply be monitored more closely.” The team also compared rates of heart problems in people who took high doses of Zocor, available widely as the generic simvastatin and less costly than brand-name Lipitor or atorvastatin.
The risk of developing diabetes proved to be the same with both drugs. But high-dose Lipitor cut the risk of heart attacks and strokes by 22 percent, compared with a 5 percent reduction in heart risk among those who took simvastatin, Ray said. He said the study shows high-dose simvastatin is not the best option.
“The net benefit of simvastatin is clearly very low and patients on simvastatin 80 mg should be moved to atorvastatin 80 mg instead. I don't think we can wait for loss of (Lipitor's) patent to stop using simvastatin 80 mg,” Ray said. The authors concluded, “Our findings suggest that clinicians should be vigilant for the development of diabetes in patients receiving intensive statin therapy.”
Currently, the National Institute for Health and Clinical Excellence, recommends an 80 mg dose of simvastatin because it is the least costly option for patients with heart disease. U.S. health regulators earlier this month recommended limiting the 80 mg dose of simvastatin because it increases the risk of muscle damage.
Libby Dowling, clinical advisor at Diabetes UK said, “This analysis of previous studies has found that high doses of statins increase the risk of developing Type 2 diabetes, yet at the same time reduce the risk of heart disease. What we don’t know from this research is whether the people being prescribed the high-dose statins were overweight as having a large waist puts you at increased risk of developing Type 2 diabetes anyway.”
Dr Sharlin Ahmed, research liaison officer at The Stroke Association, said, “Every patient needs to be assessed and treated on a case by case basis and the risk of developing diabetes as a result of taking statins should be weighed up against the potential risk of having a heart attack or stroke.”
More than seven million people in Britain now take statins - as many as one in three adults over the age of 40.
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