Statins Reduce Cardiovascular Risk in Patients with Diabetes

By Charles Bankhead
OXFORD, England, Jan. 10 -- All diabetes patients may benefit from statin therapy to reduce their risk of occlusive vascular events, suggested a prospective meta-analysis here.
In the analysis of nearly 20,000 patients with type 1 or 2 diabetes, all-cause mortality decreased by 9% with every 1 mmol/L decline in LDLs, the international Cholesterol Treatment Trialists' Collaborators reported in the Jan. 12 issue of The Lancet.
The benefit was similar to the 13% reduction in mortality risk in nondiabetic patients, they found.
Diabetic and nondiabetic patients alike had a 21% reduction in vascular events with each mmol/L decrease in LDLs. Statin therapy significantly reduced the risk of myocardial infarction and coronary death, coronary revascularization, and stroke.
"Among people with diabetes the proportional effects of statin therapy were similar irrespective of whether there was a prior history of vascular disease and irrespective of other baseline characteristics," the authors wrote.
They concluded, "Since the absolute size of the benefit depends chiefly on the absolute reduction in LDL cholesterol that is achieved, present guidelines might need to be revised to ensure that a statin regimen which is sufficient to produce a substantial reduction in LDL cholesterol is considered for all people with diabetes, irrespective of whether vascular disease has developed and irrespective of lipid profile."
In a previous meta-analysis of 14 randomized trials of statin therapy, the Cholesterol Treatment Trialists' Collaboration found that every 1 mmol/L decline in LDL cholesterol was associated with about a 20% decrease in the risk of vascular events in a wide range of high-risk patients. However, some uncertainty persisted about the effects of statins in patients with diabetes.
"For example, there is little information about the separate effects on major coronary events … on stroke, and on the need for coronary revascularization," the authors noted. "Moreover, whether the benefits of statin therapy are worthwhile in people with diabetes who do not have any history of occlusive vascular disease is unknown."
In an effort to eliminate some of the uncertainty, the investigators performed prespecified analyses of the 18,686 diabetic participants (1,466 type 1 and 17,200 type 2) in the 14 statin trials included in the original meta-analysis. The trials included a total of 71,370 nondiabetic patients. Clinical outcomes were defined in terms of the effects associated with each 1 mmol/L reduction in LDL.
During a mean follow-up of 4.3 years, 3,247 major vascular events occurred in patients with diabetes. The per-mmol/L decline in all-cause mortality was statistically significant in diabetic (P=0.02) and nondiabetic patients (P<0.0001). The overall benefit for patients with diabetes reflected a significant reduction in vascular mortality (relative risk: 0.87, 95% CI: 0.76 to 1.00, P=0.008) and no effect on nonvascular mortality (RR: 0.97, 95% CI: 0.82 to 1.16).
Among diabetic patients, statin therapy was associated with a:
22% reduction in the risk of MI or coronary death (P<0.0001)
25% reduction in the rate of coronary revascularization (P<0.0001)
21% reduction in stroke risk (P=0.0002)
After five years, 42 fewer diabetic patients had major vascular events per 1,000 treated with a statin.
In a commentary that accompanied the report, Bernard M. Y. Cheung, M.D., of the University of Birmingham in England, acknowledged statins as one of the "most notable triumphs of modern medicine." However, he cautioned that statins are not a panacea, as treated patients remain at risk for other causes of mortality and morbidity.
Dr. Cheung also noted that the new meta-analysis did not include three recent negative trials of statin therapy in patients with diabetes. However, each of the negative trials demonstrated a trend toward lower event rates, favoring statin therapy, he added.
"In any case, treatment decisions should be based not on the reduction in relative risk but on the reduction in absolute risk or its reciprocal, the number needed to treat," Dr. Cheung wrote.
"Additionally, one should consider life expectancy, concomitant diseases, and quality of life," he continued. "Apart from drug treatment, one must not forget the importance of lifestyle changes."
The Cholesterol Treatment Trialists' Collaborators disclosed that several members of the writing committee had received reimbursement of travel costs to meetings from representatives of the pharmaceutical industry. They also noted that most of the trials included in the meta-analysis were supported by the pharmaceutical industry. Dr. Cheung disclosed financial support from statin-makers to organize, attend, or speak at scientific conferences.
Primary source: The LancetSource reference:Cholesterol Treatment Trialists' (CTT) Collaborators. "Efficacy of cholesterol-lowering therapy in 18,686 people with diabetes in 14 randomized trials of statins: a meta-analysis" Lancet 2008; 371: 117-125. Additional source: The LancetSource reference: Cheung BMY, "Statins for people with diabetes" Lancet 2008; 371: 94-95.