Age and gender bias in statin trials.
Cardiovascular disease is strongly age-related, and is the leading cause of death in older people. Several well-publicized trials have recently reported that statin drugs (HMG CoA reductase inhibitors) are effective in lowering cholesterol and in reducing the risk of myocardial infarction and stroke. In order to determine whether the results of these trials are relevant to our ageing population, we examined the representation of older people and women in randomized controlled trials of statin drugs. A systematic search of the medical literature from 1990 to 1999 was done to identify randomized placebo-controlled trials of statin drugs which evaluated clinical end-points-myocardial infarction, stroke or death. We identified 19 trials: 15 secondary prevention and four primary prevention. The mean age, age range and gender of the participants in these trials were determined. In the secondary prevention trials, the total number of patients randomized was 31683, with a combined mean age of 58.1 years. No trial enrolled people beyond the age of 75 years, and only 23% of the trial population was female. The four primary prevention trials randomized a combined total of 14 557 subjects with a mean age of 56.9 years. Only 10% of study participants were female. Statin drug trials have suffered from age and gender bias, having been mainly conducted in middle-aged male populations. The extrapolation of evidence from these trials to older people and women needs further evaluation.