A new meta-analysis, combining data on more than 18000 diabetic patients across 14 trials, helps support the current wisdom that all diabetic patients at “sufficiently high risk” for vascular events can benefit from statins The study is the latest analysis from the Cholesterol Treatment Trialists (CTT) Collaborators and indicates that statins reduce deaths from vascular causes in diabetics, without increasing the risk from non-vascular causes, to a degree similar to that seen in nondiabetics.
According Dr Colin Baigent (Oxford University, UK), one of the CTT collaborators, the findings should help quell debate spurred by the recent 4D and ASPEN trials, which found no clear benefit of statins in diabetics. In the current meta-analysis, the effects of statins were not only similar in people with and without diabetes, they were also similar in diabetics with and without vascular disease, an important finding since many of the diabetics in the study did not have vascular disease at baseline.
Baigent also stated that, "It also did not matter whether they were young or old, men or women, obese or not obese, had mild kidney disease or not." "Most important of all, it didn’t matter what their starting cholesterol was, so even people with below-average LDL [low-density lipoprotein] cholesterol: if they were diabetic and at increased risk, they benefited from the statin."
The CTT investigators analyzed baseline and follow-up data on 18,686 type 1 and 2 diabetics, in whom a total of 3247 major vascular events occurred over a mean of 4.3 years follow-up. Outcomes were considered in relation to those of more than 71,000 nondiabetics.
They report that every mmol/L reduction in LDL cholesterol in diabetic patients was associated with a 9% reduction in all-cause mortality, a number similar to the 13% reduction seen for the same degree of LDL-lowering in nondiabetics. Vascular deaths were reduced in tandem with cholesterol-lowering, as were rates of myocardial infarction (MI), coronary death, revascularization, and stroke. Nonvascular deaths, however, were not significantly increased.
"There has been some debate over whether statins are as effective in people with diabetes as they are in people without diabetes," Baigent commented. "In particular, lipid metabolism in people with diabetes is a little bit different to the general population and so there have been some concerns that perhaps statins might not be quite as effective when the lipid disorder was different. . . . What we showed is that the effects of statin therapy on major vascular events are entirely similar in people with diabetes as they are in people without diabetes."
- In type 2 diabetes, triglyceride levels are frequently elevated, and HDL cholesterol levels are suppressed. However, in type 1 diabetes, HDL cholesterol levels are generally normal or even elevated. Meanwhile, LDL cholesterol levels among patients with both type 1 and type 2 diabetes are frequently reflective of those of the general population and are not necessarily elevated.
- The current study suggests that statins are associated with significant mortality and cardiovascular benefits among patients with diabetes. These results are similar to those of interventions with statins for patients with other high-risk conditions for cardiovascular disease.
Cholesterol Treatment Trialists’ (CTT) Collaborators. Efficacy of cholesterol-lowering therapy in 18,686 people with diabetes in 14 randomised trials of statins: A meta-analysis. Lancet 2008; 371:117-125.
Cheung BMY. Statins for people with diabetes. Lancet 2008; 371:94-95.