Jose Gutierrez and colleagues performed a sex-based meta-analysis, seeking to determine if statins yield a similar protective effect on both men and women in preventing recurrent cardiovascular events. In a paper published in the Archives of Internal Medicine, they report the results of their meta-analysis of 11 secondary prevention, double-blinded, placebo-controlled trials, which included 43, 193 patients (11,229 women and 31,962 men).
Overall, statin therapy was associated with a significant reduction in overall CV outcomes for both men and women. For all-cause mortality and stroke, however, the benefit in women did not achieve statistical significance.
All CV outcomes:
- women: RR 0.81, CI 0.74-0.89
- men: RR 0.82, CI 0.78- 0.85]
- women: RR 0.92, CI 0.76-1.13
- men: RR 0.79, CI 0.72-.87
- women: RR 0.92, CI 0.76-1.10
- men: RR 0.81, CI 0.72-0.92
The smaller sample size of women is one possible explanation for the lack of a significant difference in mortality and stroke, according to the authors. Other factors — including the worse cardiovascular profile of women and lower use of antiplatelet agents in women — might also play a role, they speculate.
In an invited commentary, Fiona Taylor and Shah Ebrahim write that it is “misleading” to focus on the lack of statistical significance in women. “The real issue is not significance but whether the effect size in women is materially different from the effect size in men,” they write, and note that “the effect on stroke and all-cause mortality in women is consistent with the effect in men.” They conclude that “statins work just as well in women as in men.”
In an editor’s note, Rita Redberg states that we should not “assume women are the same as men.” She writes that “unless we increase inclusion of women in clinical trials and report sex-specific data, there will never be sufficient data to achieve optimal care of all of our patients.”
Here is the press release from Archives:
Statins Appear Associated with Reduced Risk of Recurrent Cardiovascular Events in Men, Women
CHICAGO – Cholesterol-lowering statin drugs appear to be associated with reduced risk of recurrent cardiovascular events in men and women, but do not appear to be associated with reduced all-cause mortality or stroke in women, according to a report of a meta-analysis published June 25 in the Archives of Internal Medicine, a JAMA Network publication.
Statins have been used to lower cholesterol levels for the last 20 years, but most of the clinical trials on the drugs have predominantly enrolled men. There have been conflicting results on the benefits of statins for women with cardiovascular disease compared with men in secondary cardiovascular disease prevention, according to the study background.
Jose Gutierrez, M.D., M.P.H., of Columbia University Medical Center, New York, and colleagues conducted a meta-analysis of 11 clinical trials (a total of 43,191 participants) to examine whether statin therapy was more effective than placebo in preventing recurrence of cardiovascular events and all-cause mortality in men and women. Researchers also sought to determine the sex-specific effect of statins on the risk of recurrent cardiac and cerebrovascular events.
“In our results, statin therapy reduced the recurrence rate of any type of cardiovascular event, all-cause mortality, coronary death, any MI [myocardial infarction or heart attack], cardiac intervention, and any stroke type. The stratification by sex showed no statistically significant risk reduction for women taking statins compared with women taking placebo for the reduction of all-cause mortality and any type of stroke,” the authors comment.
However, the authors observe that the results of their meta-analysis “underscore” the low rate of women being enrolled in cardiovascular prevention clinical trials.
“Women represented only a fifth of the studied sample, limiting the strength of our conclusions. In our results, the benefit associated with statin administration in women did not reach statistical significance compared with placebo in at least two outcomes, all-causes mortality and any stroke type. The reason for this difference is uncertain. One possibility is that the small sample size of women limits the power of the study,” the authors note.
The authors conclude “this meta-analysis supports the use of statins in women for the secondary prevention of cardiovascular events.”
(Arch Intern Med. 2012;172:909-919)
Invited Commentary: Statins Work Just as Well in Women as in Men
In an invited commentary, Fiona Taylor, Ph.D., HonM.F.P.H., and Shah Ebrahim, D.M., F.R.C.P., of the London School of Hygiene and Tropical Medicine, England, write: “Focusing on a lack of statistical significance in the findings for women is misleading.”
“The real issue is not significance but whether the effect size in women is materially different from the effect size in men. Over-interpretation of imprecisely estimated effects is a serious problem in meta-analyses and in primary studies,” they continue.
“In the study by Gutierrez et al, the effect on stroke and all-cause mortality in women is consistent with the effect in men. If a statistical test is wanted, the appropriate Р value is for the sex interaction for the outcome by sex. We suggest that statins work just as well in women as in men,” the authors conclude.
(Arch Intern Med. 2012;172:919-920)