Results of a randomised trial in this week’s issue of THE LANCET suggest that people with type 2 diabetes could benefit from cholesterol-lowering therapy with statins to reduce the risk of cardiovascular disease, even when they do not have high cholesterol concentrations.
Many recent studies have shown the benefits of statin therapy to reduce the risk of cardiovascular disease in various groups of patients. Whether most patients with diabetes (who are known to be at increased cardiovascular risk) should receive cholesterol-lowering therapy remains unclear, especially for those patients who do not have High cholesterol.
Helen Colhoun from the University College Dublin, Ireland and colleagues assess the effectiveness of atorvastatin for the primary prevention of major cardiovascular events in patients with type 2 diabetes without high concentrations of LDL-(‘bad’) cholesterol. Around 2800 patients (aged 40–75 years) in 132 centres in the UK and Ireland were randomly assigned either placebo (1410 patients) or atorvastatin (1428 patients). Patients had no previous history of cardiovascular disease and had low LDL cholesterol concentrations (around 4 millimoles per litre or less).
Average follow-up was around 4 years after study enrolment. The primary outcome measure of the study—acute coronary heart disease events, coronary revascularisation, or stroke—was reduced by around a third among patients given atorvastatin compared with those given placebo. Atorvastatin reduced the death rate by 27% compared with placebo. Strokes were reduced by 48%. Professor Colhoun comments: Atorvastatin 10 mg daily is safe and efficacious in reducing the risk of first cardiovascular disease events, including stroke, in patients with type 2 diabetes without high LDL-cholesterol. No justification is available for having a particular threshold level of LDL-cholesterol as the sole arbiter of which patients with type 2 diabetes should receive statins. The debate about whether all people with this disorder warrant statin treatment should now focus on whether any patients are at sufficiently low risk for this treatment to be withheld.
In an accompanying commentary (p 641), Abhimanyu Garg (University of Texas, USA) concludes: “While landmark trials like CARDS increase our confidence in lipid-lowering drug therapy for prevention of coronary heart disease in patients with type 2 diabetes, it is still prudent to assess an individual’s risk-benefit ratio before recommending long-term statin therapy. Thus more models need to be developed, such as the UK Prospective Diabetes Study risk engine, to assess coronary heart disease risk in patients with type 2 diabetes. For patients with type 2 diabetes at moderate to low risk of coronary heart disease, maximal lowering of lipids with diet, exercise, weight loss, and rigorous glycaemic control must be attempted before considering lipid-lowering drugs”.
Atorvastatin is one of the statins, a class of drugs approved by the U.S. Food and Drug Administration (FDA) to lower cholesterol levels. Epidemiological studies have suggested that individuals taking statins to treat high cholesterol seem to have a reduced risk of developing Alzheimer’s disease.