BOSTON — Statin therapy significantly reduces the risk of sudden cardiac death independent of its effect on cholesterol, according to a metaanalysis of 12 studies.
“This is not a surprise because statins have a variety of effects, and it is these effects both within the heart and outside the heart that we think explain this finding,” said Dr. Derek Exner of the University of Calgary (Alta).
Multiple randomized trials have shown that statin therapy significantly reduces mortality in patients with ischemic heart disease, he said in an interview. However, their impact specifically on sudden cardiac death (SCD) has been unclear, although there is growing evidence that they have antiarrhythmic effects in addition to possible effects on platelet function and vascular tone.
His study, presented as a poster at the annual meeting of the Heart Rhythm Society, included 41,167 patients in 12 long-term, randomized, placebo-controlled trials of statin therapy for either primary or secondary prevention of coronary artery disease. During the mean follow-up of 3 years, 20% of the deaths (912) were categorized as SCDs—425 in the statin groups and 487 in the placebo groups. Deaths by all causes were observed in 2,243 and 2,708 of the statin and placebo groups, respectively.
By using a random effects model, Dr. Exner calculated that statin therapy reduced the odds of death by 22% and the odds of SCD by 14%, independent of changes in LDL and HDL cholesterol levels. The reduction in the odds of SCD did not differ by sex or by diabetes status. However, the magnitude of benefit was greater in secondary prevention, with an odds reduction of 18%, compared with 5% in primary prevention.
“This is a fairly large sample size of over 40,000 patients,” Dr. Exner said. “It's the best we can do with the data, and we can feel pretty confident in the results. It suggests that the SCD protection is not explained, at least in a large part, by the change in cholesterol. Could it be partly related? It could be, but not statistically.”