Statins are cholesterol lowering drugs that are widely prescribed to patients at increased risk of heart attacks or strokes. Though evidence from randomized trials has shown that statin therapy reduces absolute risk among a wide range of individuals there has been uncertainty about their benefits in older people, along with uncertainty about how big a risk factor cholesterol is.

In the past, trials that looked at the effect of statin therapy reported statistically valid cardiovascular risk reductions in the 65-70 age group but statin therapy is often discontinued in patients 75 and older in part because of this question around risk (e.g. myopathy) and benefit.

A new meta-analysis seeks to clear that up and does, with a few qualifications. The authors distilled 28 randomized controlled trials, including 186,854 patients, 14,483 of whom were aged over 75. They found that statins reduced risks of major vascular events by about a fifth per 1 mmol/L reduction in LDL cholesterol among all age groups. For major coronary events the overall reduction was about a quarter per 1 mmol/L reduction overall, but ranged from about 30% in those aged <55 years to around 20% in those aged >75. The relative risk reductions for stroke and for coronary revascularization (coronary stenting or bypass surgery) were similar in all age groups. 

The analysis shows that the reduction in major vascular events – 21% per 1 mmol/L reduction in LDL cholesterol overall – is similar and statistically significant in all age groups, including those over 75 years of age. For major coronary events the overall statistical reduction is 24% per 1 mmol/L reduction in LDL, but decreases slightly with age. The study also shows no increased risk of non-vascular mortality or cancer in any age group.

The researchers noted that their results were influenced by four trials done exclusively among patients who had heart failure or were on renal dialysis. Statins have not been shown to be effective in these people, and are not recommended for them. When these participants were excluded, similar reductions in risk were seen across all age groups, including for major vascular events and cardiovascular mortality. A slightly smaller reduction in the risk of major coronary events with increasing age persisted.

But in the primary prevention setting (ie, in individuals with no known history of vascular disease), two individuals aged 63 years and 78 years with otherwise identical risk factors might have projected major vascular event rates of 2.5% versus 4.0% per year, respectively. Reducing those risks by a fifth with a 1.0 mmol/L LDL cholesterol reduction would prevent first major vascular events from occurring each year in 50 individuals aged 63 years and 80 individuals aged 78 years per 10,000 people treated.