Statin therapy should be considered for all diabetic individuals who are at sufficiently high risk of vascular events, according to a new study published in the Jan. 12 issue of The Lancet.
At least 170 million people worldwide are estimated to have diabetes mellitus, and this number is predicted to more than double by 2030. The rapid rise in prevalence is mainly attributable to an increased incidence of type 2 diabetes. Since both types of diabetes are associated with a substantially increased risk of atherosclerotic vascular disease, identification of treatments for the prevention of major occlusive vascular events is a public-health priority, according to the authors.
Cholesterol Treatment Trialists' (CTT) Collaborators, who conducted the trial, analyzed data from 18,686 individuals with diabetes (1,466 with type 1 and 17,220 with type 2) in the context of a further 71,370 without diabetes in 14 randomized trials of statin therapy. The weighted estimates were obtained of effects on clinical outcomes per 1·0 mmol/L reduction in LDL cholesterol.
During a mean follow-up of 4.3 years, there were 3,247 major vascular events in people with diabetes. There was a 9 percent proportional reduction in all-cause mortality per mmol/L reduction in LDL cholesterol in participants with diabetes, which was similar to the 13 percent reduction in those without diabetes. The finding reflected a significant reduction in vascular mortality and no effect on non-vascular mortality in participants with diabetes, the CTT reported.
The collaborators also said that there was a significant 21 percent proportional reduction in major vascular events per mmol/L reduction in LDL cholesterol in people with diabetes, which was similar to the effect observed in those without diabetes. In diabetic participants, there were reductions in myocardial infarction or 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. After 5 years, 42 fewer people with diabetes had major vascular events per 1,000 allocated statin therapies, the CTT reported.
The main report of the CTT Collaboration showed that statin therapy safely reduces the 5-year incidence of major coronary events, coronary revascularization and stroke by about a fifth per mmol/L reduction in LDL cholesterol, largely irrespective of initial lipid profile or other baseline characteristics. Larger reductions in LDL cholesterol were associated with greater proportional reductions in major vascular events, which meant that the expected absolute benefit was proportional to the baseline risk of a participant and the absolute reduction in LDL cholesterol achieved by statin therapy.
The CTT believes that the meta-analysis “showed convincingly that the proportional benefits of statin therapy on major vascular events were similar in a wide range of individuals with diabetes, including those with no previous history of vascular disease, and benefits were similar to those observed in people without diabetes.”
Therefore, the collaboration concluded that the cost-effectiveness of treatment for a person at a specific absolute level of risk of major vascular events, irrespective of whether diabetes is present, will be much the same. The Heart Protection Study previously showed that a generic statin regimen producing a mean reduction of about 1 mmol/L was cost effective (i.e., cost saving or costing less than $4,907 U.S. (£2,500 GBP) per life-year gained) in people who have risks of a major vascular event as low as about 1 percent per year. The findings suggest that such treatment is likely to be cost effective for almost all people with diabetes, the CTT concluded.