Statin therapy appears to reduce the risk of recurrent stroke among patients with diabetes or the metabolic syndrome to the same degree that it does in patients who have neither disorder, according to a planned post hoc analysis of data collected in the Stroke Prevention by Aggressive Reduction in Cholesterol Levels clinical trial.
However, since patients with diabetes start off with a much higher risk of recurrent stroke, their risk remains higher than that of nondiabetic patients even after statin therapy, Dr. Alfred Callahan of Vanderbilt University, Nashville, Tenn., and his associates reported online June 13 in Archives of Neurology.
Until now, no information has been available on the effect of statin treatment on secondary stroke prevention in patients with type 2 diabetes or the metabolic syndrome, the investigators noted.
The primary conclusion of the SPARCL clinical trial was that atorvastatin (Lipitor) reduced stroke risk in general. For this secondary analysis, Dr. Callahan and his colleagues assessed stroke risk in 794 adults who had type 2 diabetes, 642 who had the metabolic syndrome, and a reference group of 3,295 who had neither disorder.
The study subjects were ambulatory men and women with no known coronary heart disease who had had ischemic stroke, hemorrhagic stroke, or transient ischemic attack (TIA) 1-6 months before undergoing randomization in the SPARCL trial. They were treated at 205 medical centers in Africa, Australia, Europe, the Middle East, North America, and South America. The mean age was 63 years, and subjects were assessed every 6 months for a mean of 5 years.
Treatment with atorvastatin decreased LDL cholesterol levels to a similar degree across the three study groups, and lowered triglycerides by 11% in the group with diabetes, 20% in the group with metabolic syndrome, and 9% in the reference group.
Despite these treatment benefits, subjects with diabetes remained at increased risk of recurrent stroke (hazard ratio, 1.62), of major cardiovascular events (HR, 1.66), and of revascularization procedures (HR, 2.39), compared with the reference group. Subjects with metabolic syndrome were at increased risk of revascularization procedures (HR, 1.78) but not of other adverse cardiovascular outcomes.
At the conclusion of the study, the rate of recurrent stroke was 18% in patients with diabetes, 11% in those with metabolic syndrome, and 11% in the reference group.
"There was no evidence of a difference in treatment effect" among the three study groups, Dr. Callahan and his associates said (Arch. Neurol. 2011 June 13 [doi:10.1001/archneurol.2011.146]).
"These results should be viewed as exploratory" because the SPARCL trial was not powered to test for subgroup effects, they noted.
However, the findings agree with those of the Cholesterol Treatment Trialists’ collaboration, which also found that the effect of statins on stroke risk was similar between diabetic and nondiabetic patients, the researchers added.
Pfizer sponsored the study. Dr. Callahan reported receiving support from Pfizer, Sanofi-Aventis, and Bristol-Myers Squibb. His associates reported ties to numerous pharmaceutical and device companies.