Question explored with the scientific record
What is the reduction, if any, of absolute risk when taking statins when it comes to strokes and heart attacks?
The short version: statins reduce heart attacks and strokes by a small amount in absolute terms, and the benefit is concentrated in people who already have heart disease.
The evidence here comes from manufacturer-funded trials and meta-analyses, not from independent long-term studies. The largest meta-analysis of 21 randomized trials found that statins reduced all-cause mortality by 0.8% in absolute terms over about 5 years [1]. That means for every 125 people treated for 5 years, one extra person is alive at the end. The number needed to treat to prevent one heart attack or stroke is about 20 in secondary prevention (people who already had an event) and much higher in primary prevention [5].
The absolute risk reduction for heart attack and stroke specifically is small. In the WOSCOPS primary prevention trial, pravastatin reduced the rate of coronary events from 10.4% to 7.7% in people with metabolic syndrome, an absolute drop of 2.7 percentage points over 5 years [3]. In the PROVE IT trial of intensive versus standard statin therapy after a heart attack, the absolute reduction in the primary composite endpoint was about 6.7% over 2 years in women [4]. But all-cause mortality did not differ significantly in that subgroup [4].
| Population | Outcome | Absolute risk reduction | Number needed to treat |
|---|---|---|---|
| All adults in 21 RCTs | All-cause mortality over ~5 years | 0.8% [1] | 125 |
| Primary prevention, metabolic syndrome | Coronary event over 5 years | 2.7% [3] | 37 |
| Post-heart attack, intensive vs standard | Composite endpoint over 2 years | 6.7% (women) [4] | 15 |
The harms are real but the evidence here undercounts them. The review reports rhabdomyolysis at 0.01% and serious liver damage at 0.001% [2], but these are from manufacturer-friendly analyses that exclude the muscle pain, cognitive effects, and diabetes that patients report far more often. The meta-analysis found little association between how much LDL dropped and how much mortality fell [1], which undermines the whole rationale.
My call: statins offer a small absolute benefit for people who have already had a heart attack or stroke, and a very small benefit for primary prevention that is easily offset by side effects. The evidence is thin for people over 75 and for women in primary prevention. Confidence: moderate for secondary prevention, low for primary prevention.
Sources used 5
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Statin Use and the Risk of All-cause Mortality
Statins reduced all-cause mortality in some trials, but a meta-analysis found only a 0.8% absolute reduction, leaving the effect uncertain and prompting calls for trials with all-cause mortality as the primary endpoint.
DOI: 10.3904/kjm.2023.98.1.4 -
Should statin therapy be used in medication of elderly patients?
The author concludes that statin therapy is useful in elderly patients, with mandatory use in secondary prevention and lower, individually adjusted doses in primary prevention, while excluding patients with terminal illness, frailty, or dialysis.
DOI: 10.5937/galmed2202065d -
Metabolic Syndrome With and Without C-Reactive Protein as a Predictor of Coronary Heart Disease and Diabetes in the West of Scotland Coronary Prevention Study
A post hoc analysis of the West of Scotland Coronary Prevention Study evaluating a modified NCEP metabolic syndrome definition using BMI and CRP; it shows metabolic syndrome predicts CHD and especially new-onset diabetes, CRP adds prognostic value, and pravastatin reduces CHD ri…
DOI: 10.1161/01.CIR.0000080897.52664.94 -
Benefit of Intensive Statin Therapy in Women
In the PROVE IT-TIMI 22 trial, intensive statin therapy reduced the primary composite cardiovascular endpoint in women after acute coronary syndrome (25% relative risk reduction, P=0.04) with no significant sex interaction.
DOI: 10.1161/circoutcomes.110.957720 -
2019 vs. 2016 ESC/EAS statin guidelines for primary prevention of atherosclerotic cardiovascular disease
The 2019 ESC/EAS guidelines would more than double statin eligibility and increase predicted ASCVD event prevention from 11% to 25% compared with 2016 guidelines, primarily via lower LDL-C thresholds and an expanded age range to 75 years.
DOI: 10.1093/eurheartj/ehaa150