Statin Benefit Same in Women as in Men at Equal Risk Levels

Pam Harrison

January 13, 2015

Billed as the most comprehensive of its kind, a large meta-analysis suggests that statin benefits in reducing "major vascular events" are about the same in women as in men when adjusted for predicted cardiovascular risk[1].

"It's unfortunate that the idea has grown up in some places that women don't benefit as much as men from statin therapy, and I think this idea has arisen because people haven't taken into account the fact that women in general develop vascular disease later in life than men," Dr Colin Baigent (Clinical Trial Service Unit and Epidemiological Studies Unit, University of Oxford, UK) told heartwire .

"But the important nuance of our message here is that we need to identify women who are at risk for cardiovascular disease and offer them statin therapy if they exceed a certain threshold of risk, because vascular disease is common, especially in older women, and prevention of that disease could be facilitated by wider use of statin therapy."

The study was published online on January 9, 2015 in the Lancet.

The Cholesterol Treatment Trialists' (CTT) Collaboration performed meta-analyses on data from 22 trials of statin therapy vs controls and five trials of more intensive vs less intensive statin therapy.

A total of 46 675, or 27% of 174 149 randomly assigned participants in these trials, were women. Individual participant data were available from all 27 trials.

In each group of trials, mean concentrations of total and LDL cholesterol at baseline were similar in women as they were in men.

All trials (n=27)

Group Total cholesterol, mmol/L LDL cholesterol, mmol/L HDL cholesterol, mmol/L Triglycerides, mmol/L
Women 5.6 3.4 1.3 1.5
Men 5.3 3.3 1.1 1.6

Major Vascular Events

"Among all 27 trials, statins reduced the risk of major vascular events by 21% for each 1.0-mmol/L reduction in LDL cholesterol (rate ratio 0.79, 95% CI 0.77–0.81; P<0.0001), with significant reductions in both women and women," investigators report.

Major vascular events included MI, stroke, the need for coronary revascularization, and cardiac death.

The proportional reductions in major vascular events for each 1.0-mmol/L reduction in LDL cholesterol seemed slightly smaller in women than in men among the 22 trials of statin vs controls, but they were still highly significant (P<0.0001) in both women, at a rate ratio (RR) of 0.85 (99% CI 0.78–0.92), and men (RR 0.78, 95% CI 0.75–0.82).

Among the five trials where more intensive therapy was compared with less intensive therapy, the proportional reductions in major vascular events among women were similar to those in men, investigators added.

The proportional reductions in major vascular events were also similar among individuals with a definite history of vascular disease.

Somewhat in contrast, statin effects in subjects with no known history of vascular disease seemed slightly greater in men (RR 0.72, 99% CI 0.66–0.80) than in women (RR 0.85, 95% CI 0.72–1.00).

Among all 27 trials, statin therapy reduced the risk of major coronary events by 24% for each 1.0-mmol/L reduction in LDL cholesterol, with significant reductions in both women (RR 0.83, 99% CI 0.74–0.93; P<0.0001) and men (RR 0.74, 99% CI 0.70–0.78; P<0.0001).

Statin therapy also reduced coronary-revascularization procedures by the same 24% percent for each 1.0-mmol/L drop in LDL cholesterol, again with no significant sex differences evident overall.

The overall proportional reduction of 15% in any stroke for each 1.0-mmol/L reduction in LDL cholesterol (RR 0.85, 95% CI 0.80–0.89) was also similar between women and men and again broadly similar at all levels of CVD risk, investigators add.

Importantly, reductions in major vascular events were also broadly similar irrespective of sex at all levels of CVD risk, including among women and men whose 5-year risk of having a major vascular event was low, at <10%.

Overall, statin therapy also produced a highly significant 12% proportional reduction in vascular mortality (RR 0.88, 95% CI 0.84–0.91) for each 1.0-mmol/L reduction in LDL cholesterol and a nominally significant reduction in deaths from unknown causes.

Finally, after adjustment for nonsex differences, there were similar proportional reductions in all-cause mortality for each 1.0-mmol/L reduction in LDL cholesterol of 10% in men (RR 0.90, 99% CI 0.86–0.95) and 9% in women (RR 0.91; 99% CI 0.84–0.99).

Statin treatment had no significant effect on cancer or cancer mortality, and there was no evidence of any difference in the safety of statin therapy between women and men.

"All of the large statin trials are represented in this analysis," Baigent emphasized.

"And what's unique about this analysis is that we have detailed information on each individual patient in each of these trials, so we've been able to do the types of analyses that are needed to demonstrate that women derive as much benefit from statin therapy as men provided they are at equivalent CVD risk.

"No other meta-analysis has been able to do this, as they did not have access to individual patient data, and in our analysis, this was true both in the primary and the secondary prevention setting."

The study was funded by the UK Medical Research Council, the Australian National Health and Medical Research Council, the British Heart Foundation, and the European Community Biomed Program. Most of the trials included in this analysis were supported at least in part by research grants from the pharmaceutical industry. Baigent reported grants from Merck Sharp & Dohme during the conduct of the study and grants from Novartis and Pfizer outside the submitted work. Disclosures for the coauthors are listed in the article.

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