Most patients with type 2 diabetes should take statins to help prevent heart disease, whether or not they have high cholesterol concentrations, new guidelines say.
The recommendations, from the American College of Physicians, call for moderate doses of statins for people with diabetes who are older than 55 and for younger patients who have any other risk factor for heart disease, such as high blood pressure or a history of smoking (Annals of Internal Medicine2004;140:644-9). The guidelines are based on the results of six studies of primary prevention and eight trials of secondary prevention in patients with diabetes.
“Given the markedly elevated risk for cardiovascular events in most persons with type 2 diabetes, preventing cardiovascular disease through aggressive management of cardiovascular risk factors is of utmost importance,” the guidelines say. “The evidence suggests that lipid-lowering medication leads to a 22% to 24% reduction in major cardiovascular events in patients with diabetes. On the basis of the current literature, statins are the agents of choice.”
The guidelines call for lipid lowering drugs to be used for secondary prevention of cardiovascular mortality and morbidity in all patients with known coronary artery disease and type 2 diabetes and for primary prevention against macrovascular complications in patients with type 2 diabetes and other cardiovascular risk factors.
For patients with type 2 diabetes who are taking statins, routine monitoring of liver function tests or muscle enzymes is not recommended except in specific circumstances.
The authors of an article accompanying the guidelines, a background paper for the American College of Physicians, Dr Sandeep Vijan and Dr Rodney Hayward of the University of Michigan, said that “almost everyone with type 2 diabetes should be on a statin.” The average age at diagnosis is 48, and even many patients under 55 years old have high blood pressure as well as diabetes, he said (2004;140:650-8).
In a meta-analysis conducted by Dr Vijan and Dr Hayward of the six primary prevention studies, the authors showed that lipid lowering drugs reduced the risk of cardiovascular outcomes (relative risk 0.78 (95% confidence interval 0.67 to 0.89); absolute risk reduction 0.03 (0.01 to 0.04) in 4.3 years of treatment). The number of patients needed to treat to prevent one major cardiovascular event was 34 to 35.
A similar meta-analysis of the eight studies of secondary prevention showed a similar relative risk (0.76 (0.59 to 0.93)) but more than twice the absolute risk reduction (0.07 (0.03 to 0.12) in 4.9 years of treatment) and a number needed to treat for benefit of 13 to 14. Most of the studies compared a lipid lowering drug with placebo but did not evaluate the effect of reaching specific cholesterol concentrations. The benefit of a fixed dose of a statin in lowering cholesterol concentrations seemed to be similar regardless of the starting concentration.
Traditionally, diabetes treatment has focused on regulating blood sugar concentrations by careful control of diet or through insulin injections to reduce microvascular disease.
Dr Vijan said the new guidelines called for moderate doses of statins. The largest clinical trial involving patients with diabetes used a dose of 40 mg of simvastatin. He said researchers were evaluating recently published studies that indicated that high doses of statins might have better results.